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FOTEC PHYSICAL OCEANOGRAPHY FINAL.REPORT ROSENSTIEL SCHOOL OF MARINE AND ATMOSPHERIC SCIENCE 4600 RICKENBACKER CAUSEWAY MIAMI, FLORIDA 33149 OCTOBER, 1983 TK 1071 FLORIDA INSTITUTE OF OCEANOGRAPHY F66 1983 830 FIRST STREET SOUTH ST, PETERSBURGj FLORIDA 33701 FOTEC PHYSICAL OCEANOGRAPHY FINAL REPORT ROSENSTIEL SCHOOL OF 10N MARINE AND ATMOSPHERIC SCIENCE 4600 RICKENBACKER CAUSEWAY MIAMI, FLORIDA 33149 VS Department of Commerce No"\ ---.stal services Center Library 22:@ 71obson Avenue Cha@:I@-tull' SC 29405-2413 Z% OCTOBER, 1983 FLORIDA INSTITUTE OF OCEANOGRAPHY 830 FIRST STREET SOUTH ST. PETERSBURGj FLORIDA 33701 FOTEC PHYSICAL OCEANOGRAPHY FINAL REPORT ROSENSTIEL SCHOOL OF MARINE AND ATMOSPHERIC SCIENCE 4600 RICKENBACKER CAUSEWAY MIAMI, FLORIDA 33149 OCTOBER, 1983 FLORIDA INSTITUTE OF OCEANOGRAPHY 830 FIRST STREET SOUTH ST. PETERSBUIRG.* FLORIDA 33701 FOTEC PHYSICAL OCEANOGRAPHY FINAL REPORT ROSENSTIEL SCHOOL OF MARINE AND ATMOSPHERIC SCIENCE 4600 RICKENBACKER CAUSEWAY MIAMI, FLORIDA 33149 'OCTOBER5, 1983 ACKNOWLEDGMENTS The project described in this report was supported by the Coastal Energy Impact Program (CEIP Grant #82-CE-CW-13-00-05-006), which is administered by the Office of Ocean and Coastal Resource Management, National Oceanic and Atmospheric Administration through the Florida Department of Community Affairs. INDEX Index I Introduction 1-2 2) Background on the Florida Current 3-17 3) Current and Temperature Profile Data 18-21 4) Temperature Section Data 22-23 5) Satellite Sea Surface Temperatures of FOTEC Data 24 6) Discussion of FOTEC Data 25-26 7) Conclusions and Recommen dations 27-28 8) Bibliography 29-32 1) Introduction This report summarizes the results of surveys of two proposed sites for a Florida Ocean Thermal Energy Conversion (FOTEC) plant near Key West. Both sites are located in the Straits of Florida as seen on the locator map in figure 14 in section 3 on data. OTEC plants extract energy and/or fresh water from the vertical temperature gradient between the warm surface water and the cold water below the thermocline in the ocean. While the source of energy in the form of solar heating of the oceans surface waters is virtually inexhaustible and free of charge, very large heat exchangers and structures are required for acceptable efficiencies of operation. Careful environmental and engineering studies are required to insure long life and low maintenance of these large capital investments. Of particular interest to the design engineers are the thermal resources upon which the plant feeds and the current induced forces the structure must withstand. These issues are both addressed in this report. Three sources of information are used to focus on the 'temperature and current structure at these sites. The first source of information is historical data collected on past cruises by various investigators and institutions. These data were collected over larger space and time scales and thus expand our knowledge. Dr. Thomas Lee of the University of Miami (RSMAS) functioned as a consultant to this project to examine the historical data which might be applicable to these sites. Second'. direct measurements made in the course of this contract of temperature and current structure. These data were collected on the R/V Bellows during the period from February 15, 1983 to February 27, 1983. Page 2 Capt. Gene Olson and Marine Technician Albert Rodriguez of Florida Institute of Oceanography (FIO) at the University of South Florida were. particularly helpful in anchoring the ship in 700-800 meter water depths and careful data acquisition respectively. Marine Technician Mark Graham and Graduate Student Jiann-Gwo Jiing at the University of Miami (RSMAS) both worked effectively preparing the profiler plus acquiring data and analyzing and plotting the data respectively. The final source of information was remotely sensed surface temperature provided by NOAA Miami SFSS. These data give some idea about the context in which the in-situ data were recorded. Owing to limitations in time and funding, the data and interpretation presented here will not be sufficient for final engineering analysis. However these data will be required for feasibility studies and for the design of a definitive study. Clearly, data gathered during weather windows in a two week period during the winter of one year will not define current and temperature variability in great enough detail. Since none have ventured into the edge of the Gulf Stream to record data at the peak of a winter storm much less a hurricane, we have little direct evidence of current magnitudes and wave induced forces to be expected at the proposed sites under extreme storm conditions. We can however recommend methods of acquiring such data using new radar and acoustic remote sensing techniques which allow the estimation of both wave and current conditions. Page 3 2) Background-on the Florida Current The Florida Current is a highly variable, dynamic current system flowing through the Florida Straits from the Yucatan Channel to Cape Hatteras. The mean downstream flow is in approxima te geostrophic balance with cross-stream pressure gradients over a large portion of the current structure (Wust, 1924). However, within the cyclonic shear zone ageostrophic conditions can prevail (Brooks and Niiler, 1977). Richardson, Schmitz and Niiler (1969) measured the velocity structure and volume transport of the Florida Current with 7 dropsonde sections between the Florida Keys and Cape Fear (Figs. 1 and 2). Downstream velocities were strongly sheared in the vertical and horizontal with a baroclinic jet located in the western side of the Straits. Volume transport were northward and increased from a minimum of 29.6 x 10 6m3 s- I off the Florida Keys near Marathon, FL., to a maximum of 53.0 x 10 6m3 a -1 off Cape Fear. The Marathon section (section I of Fig. 2) was located very near the proposed FOTEC sites and will serve as useful data for comparison with site specific measurements. This average downstream velocity section was derived from 9 dropsonde transects between June 13 - July 4, 1966. The averaging tends to smooth out the velocity structure, making the upper layer high speed core of 140 cm s- 1 broader than what actually occurred on any single transect. Between May 3 and June 8, 1972 Brooks and Niiler (1975) made 16 dropsonde and CTD transects across the Florida Current along the 81 044'W meridian between Key West and Matanzas, Cuba. This section is located approximately 60 km upstream of the proposed FOTEC sites. Ensemble- averaged profiles of the downstream velocity (u), cross-stream ILI' TV .26. 34. CAN F9AR Re J&CKSONVILLC 21. CAPIE KI"I0zDT X. FORT P19RCC Vt. WAT4)iJLA SHOAL SIR 09L MIAMI amid @A? CAT .wt 01 AS TRAITS SAL NIC" I Go- I'v Ile. fly Fig. 1. Florida Current transport sec tions (from Richardson et al ISO- @' (00-ov. 11W 2&-31? 20.51 ILIA. M ?01 30 40 so TO W W 'o to 30 .0 &0 40 70 0 to '00 too 00 ei@ 301@ 11WA rM ?00 00" too .000 .00 100, 400 AkY.AUGU 0 196, Ay. JUK iso-2.'.30-207) RM. 0 .01 20 50 40 50 60 70 60 W .00 001,20 q* 440 1-21! 44 Pbb? AkY,ALKAAT if iiro"13-2 (b) 12 00 MA'. JQK JUN E JAY r9GO Fig. 2. Downstream velocity structure: isotachs are in cm S The 0 cm s-l isotach not presented could not be drawn with comparable confidence. Arrows at the top of each diagram show the location where the mean surface current is zero, (a) Sections, 1, 11, 111 and IVA., (b) Sections IVB, V, VI and VII (from Richardson et al., 1969). 0 J"'Y Page 4 velocity (v) temperature and salinity from Station 9 of these transects, is shown in Fig. 3. Station 9 was located at approximately the same isobaths as the proposed FOTEC sites. , These data show the large variability of currents at this site. Current speeds ranged from about 20 to 170 cm s- 1 in the upper layer during the one month experiment. However, temperature variations were much smaller. Surface temperature ranged from about 25 0C to 280C and near bottom temperatures were nearly constant at about 5 0C, giving-a vertical temperature difference from the surface to 800 m of 20 to 23 0C. The mean downstream velocity field is shown in Fig. 4. The magnitude and pattern of the eastward flow is similar to the Richardson et al., (1969) section at Marathon (Fig. 2, section 1) . However, off Key West a we'stward, mean f low of 20 cm s was observed on the northern side of the straits. This counterflow was found on 13 out of the 16 transects with current speeds reaching 80 cm s- I toward the west. Similar features have been observed all along the western boundary of the Florida Current between Miami and Cape Hatteras and have been described as northward traveling cold cyclonic eddies (Lee, 1975; Lee and Mayer, 1977; Lee, Atkinson and Legeckis, 1981; Lee and Atkinson, 1983). These eddies form in conjunction with offshore meanders of the Florida Current on a weekly time scale and their passage by a prospective FOTEC plant would produce a current reversal and upwelling of cold deeper Florida Current water. Chew (1974) observed an offshore meander of the Florida Current in the vicinity of the proposed FOTEC sites (Fig. 5). Strong upwelling is indicated north of the offshore meander by the uplifted isotherms (Figs. 5 and 6). The domed isotherms and topography of the 15 0C surface are U (2) (CM/20c) VM (CM/"C) .60 0 60 no Ito .60 a 6? 1!0 120 0. 200- 200. 09 :E 400- "a 400 Z 2 z X 600. x 600- r6 goo Wo. WOO low b TEMPERATURE (10 SALINITY N.) 0 1? 20 30 34 3$ 36 37 38 0 A_ 200_ 200 4DO. 400. ---- tF", r 600- 6W. Boo- 1000 1000 Fig.13. The data ensemble for Station 9: (a) downstream average velocity, U(z); (b) cross-stream average velocity, V(z); (c) temperature; (d) salinity (from Brooks and Niiler, 197.5). 3 5 7 4 9 10 11 13 Is 17 K At 21 STATtON 10 70 -to 40 so 60 70 to 90 K)O 110 120 no KILOMETERS a I A I A Ad A At A I A 100 110 too so 4A 200 0 60 20 300- 40 Z 400- 503- 7001 Fig. 4. The ensemble-averaged downstream velocity field (from Brooks and Niiler, 1975). DRY TORTUGAS SOMBRERO,KtY 06 050 00 350 HABANA Fig. 5. Depth (m) contour of the ISC surface with drogue tracks superposed, August 1971 (from Chew, 1974). SEA is? - - - - - 138 CTD 26 159 CT027 CT028 141 142 CTO ZS STATIOW NO. LEVEL 0- - - - - - - - - - - - - - - - - 2MI too 21' i0o 20 300 - --- - - - - - - 14 400 - - - - - - - - - - - -- 12' 500 - - - - - - - - - - - - - -- 600 -- - - - - - - - - - - - - -- 8 700 - - - - - - - - - - - - ---- - - - - - - - - 0 5 10 15 20 Km, H-41, 171 -1--Tj 0 5 10 NAUTICAL MILE Fig. 6. Vertical distribution of temperature and drogue positions at Sombrero Key section (from Chew, 1974), see Fig. 5. Page 5 both indicative of the presence of a cold cyclonic eddy north of the offshore meander. Niiler and Richardson (1973) have estimated the mean transport off Miami at 32.0 x 10 6m3s-1 with energetic fluctuations occurring on seasonal, 2-15 day and tidal time scales. Their data were reported as transport time series and shown in Fig. 7. They concluded that there was little energy between the 15 day and seasonal periods. The total 6 3 -1 fluctuation bound was about 19 x 10 m s with a maximum of 38.2 x 6 3 - 1 6 3 -1 10 m s in summer and a minimum of 19.0 x 10 m s in winter. Seasonal variations were on the order of +3 x 10 6m3s-1and accounted for about 45% of the observed variability. Fluctuations within the 2-15 day period band also had amplitudes of +3 to 4 x 10 6m3s-1 and' appear to produce 40 to 50% of the total variance. Tidal fluctuations occurred with both diurnal and semi-diurnal periods, again with amplitudes of +3 to 4 x 10 6m3s-1 and accounted for 10-20% of the variability (Schmitz and Richardson, 1968; Brooks, 1979). Low-frequency Variability (a) Current Profiling Results Fluctuations of the Florida Current in the 2-15 day period range were observed by' Pillsbury (1891) and later by Parr (1937.). Schmitz and Richardson (1968) reported east-west meanders of the Florida Current occurring on a one-week scale with amplitudes of about 5 km. DUing (1975) 'analyzed 2 weeks of current profiles sampled from 4 ships anchored off Miami and noted a barotropic current meander with a 4 to 6 day time scale (Fig. 8). Comparison of the ship measured transport data 35 - 1065 1970 IS68 z J. 0 30 - 19,10 1969 (L 7 20 F M 4 M i i A S 0 N D i F m Fig. 7. Florida Current transports of Niiler and Richardson, 1973, replotted (Molonari, personal comunication). PILLSBURY AM 71 V-COMPOKNT ------ !@ ---- -11@@ ...... _7@ @------ M! ------- 0 M no 1?0 M 170 130 2W zQ 2 230 20MO U v 60 M 200 130 100 OW Ito 140 90 t4o 200 v ?0 420 300 so A 30 goo, (f 10 400 00 M 0 60 LJJ k 40 .10 500 20 3-0 WO 0 700 40 .20 .510 -50 -50 .10 .10 .10 IL 50 .4; 0 .100 10 10 0 -2D -' -60 0 0 0 OW 19 19TI ANE 9 6 7 0 0 10 It 02 13 14 15 16 17 to Hn 010 Fig. 8 Isotach contours of north-south component (cm s from Project SYNOPS 71. Solid lines denote northward flow, dashed lines southward flow. Top Scale shows profile numbers from current profiling for 2 weeks through the core of the Floirda Current (from Kielmann and Duing, 1974). Page 6 with transport estimated from the electrical potential on a submarine cable off Jupiter, FL., indicated that the several day "meander" was produced by a wave traveling to the north at 47 cm s- I and wave length of 200 km. Diding described 2 cases for meanders: deep southward flow appeared to occur over the Miami Terrace during an offshore meander (current axis displaced to the east) and deep northward flow occurred over the Terrace during an onshore meander stage (axis displaced to the west). In general it appeared that flow variations on the cyclonic shear side of the axis were about 180 0 out of phase with the anticyclonic side. More recently Brooks (1979) found similar results from detailed dropsonde transects of the Florida Current off Miami over, an 83 day period in the summer of 1574 (Fig. 9). Transport fluctuations with periods of 2-14 days were highly coherent and in phase at stations in the cyclonic shear region as were stations in the anticyclonic region, but the two regions were about 180 0 out of phase. Brooks also found fluctuations in the total transport that were visually coherent and in phase wilth th.e- variations on the anticyclonic side. During the experiment the current axis meandered a total distance of approximately 24 km. An offshore (onshore) meander was associated with a transport increase (decrease) on. the eastern side of the current, a transport decrease (increase) on the western side and an increase (decrease) of total transport. (b) Moored Current Meter Stations Current records from an array of near bottom current meters (Fig. 10) spanning the Florida Straits at the same location and time as the ed'cd 79050, 79*40' 79*30' 79*20' 2e00'. 0 a 0 0 Md 1 3 4 6 6 9 to 0 0 0 C4 25 *46- Topography of Ibe experimental section. lsobaths in meters. b) MEASURED VALUES TIDAL RESIDUALS EAN TOTAL ko A A N.. M1 1 -1 A TRANSPORT / -V STA 2 (17 ob 3 %v41;r _-w 4 5 C. 6 k- A -AV FV w - "I - 1A A_ I + 9 -Vyv. V SCALE A AL 10 V w V It J_-AL IT I ", V \p V, 12 6JALAA -.4", 6.c@ L 13 DATE02741 5/23 6/1 111 8/1 W33 6A I I " I -,-i -A- 'Aa- DAYS 0 20 40 60 so 0 4 60 so Transport versus time. The top curves represent total transport through the section. The remaining curves represent transport at the individual stations. The left-hand column represents time series of measured values of transport. The right-hand column represents the series after tides are removed. Transport is in units of Hr ml s-1. Event markers are at days 10. 19, 26.39.55.66 and 78. Fig. 9. Transport fluctuations from dropsonde sections across the Florida Current. a) Station locations; b) Detided transports (from Brooks, 1979). 26 30' C3 % 40 112 BOCA re RAT014 Rio N6 R9 260 Ou @Ix N3o R MIAMI' R N R 30' 60600, 79".30, 0 250 Re N, CUR71EINT .5oo ARRAY Nj 750 MAR.-AUG..1974 U*fPA-o2ffw0*4m& mv), NOVA "2M*.*4W-& - - f, (romis"I - PdOVA 0 10 20 30 40 50 60 TO 60 90 WO - KLOMETERS a) Plan view of the Florida Straits with mooring sites. b) Cross-stream mooring array with vertical section of the mean flow and mean tem- perature distribution base4 on observations from March to August, 1974. made by Nova University. Fig. 10. Some previous mooring positions in the Florida Straits (from Duing et al., 1977). @R' Page 7 Brooks dropsonde measurements showed energetic fluctuations of the downstream component with well-defined spectral peaks at periods of 9 to 12 days that were coherent across the entire Florida Straits (Duing, Mooers and LeeP 1977). The downstream coherence scale of these fluctuations was estimated at 55 km from a current meter array along the continental slope (Lee, Brooks and DUing, 1977). Current spectra from the Florida Straits generally show a decrease of energy toward the very low frequencies (Dding et al., 1977) which appears to be typical of continental shelves (Niiler, 1976) and in contrast to spectra from the deep ocean (e.g., from side D; Thompson, 1971). The most energetic motions in the Florida Current appear to occur with periods of 8 to 12 days, with smaller but still significant fluctuations occurring at periods of 4 to 5 and 2 to 3 days (DUing et al., 1977; Mooers and Brooks, 1977; Brooks, 1979). (c) interpretation of Low-frequency Fluctuations In the open ocean subinertial motions are largely governed by planetary Rossby wave. Along continental margins and in Straits topographic Rossby waves or continental shelf waves (CSW's) can occur which have a higher- frequency cut-off than do open ocean Rossby waves. Brooks (1975) investigated stable barotropic CSW's in the Florida Straits using a realistic bottom profile with a baroclinic, horizontally sheared steady current. The lowest mode wave properties appeared to agree with observations reasonably well, i.e., periods of 10-12 days, wave length of 200 km and southward propagation of 20 cm s- 1. Schott and DUing (1976) found that a barotropic CSW with similar wave properties produced the best fit to current observations from an Page 8 along-axis array of lower layer moorings. Approximately 70% of the observed variance could be attributed to the barotropic mode. Similar results were found by Mooers and Brooks (1977) and DUing (1975). Continental shelf wave theory predicts a 180 0 cross-stream phase difference between currents on the shallow Miami Terrace and the deep region of the Florida Straits, which was observed by DUing et al. , (1977) and Brooks (1979). In the presence of the horizontally sheared Florida Current northward propagating CSW' s are also possible (Brooks, 1975; Nii1er and Mysak, 1971). The most probably generating mechanism for CSW's is usually attributed to Ekman suction due to wind stress curl over the Straits (Brooks, 1975; Schott and DUing, 1976; DUing et al., 1977). Significant coherence was found by DUing et al., (1977) between the downstream flow and wind stress curl in the 10 to 13 day period band, with the curl being nearly in quadrature with the downstream current. Niiler and Mysak (1971) found that uns table barotropic waves could, exist in. the Florida -Current in the vicinity of the Blake Plateau. These waves propagated northward at a period of about 10 days and wave lengths of 150 to 200 km. Schott and DUing (1976) reported that rescaling the Niiler and Mysak dispersion relation for topography and current conditions in the Florida Straits indicated only stable waves with lengths of 100 km for the 10 day period. (d) observations of Eddies On the western side of the Florida Straits, Lee (1975) and Lee and Mayer (1977) have observed cyclonic, cold-core eddies embedded in the Florida Current front. The eddies occur during periods.of offs hore Page 9 meanders and have horizontal dimensions equivalent to the meander (10' s of kms) . They propagate to the north at the same phase speed as the meander (30 to 70 cm s- 1) and appear to grow as the meander develops. They occur on the average of about 1 per week and have life spans of about 1 to 3 weeks. Satellite I.R. images ftegickis.. 1975: Stumpf and Rao, 1975) suggest that the eddies evolve from growing Florida Current meanders. Similar eddies have been observed along the Loop Current cyclonic front in the Gulf of Mexico (Maul, 1977) and north of the Florida Straits (Lee et al., 1981; Lee and Atkinson, 1983). Evidence for the occurrence of these features in the vicinity of the proposed FOTEC plant is given in Figs. 4, 5 and 6. (e) Speculation Concerning Generation of the Low-frequency Fluctuations If the apparent meteorological influences are more than coincidental, then the Florida Current may be viewed as one large system where disturbances generated by the winds in the band of 2 to 15 day period can propagate either north or south along the Straits because of the sheared current. Wave speeds in the upper layer range from 30 to 70 cm s- I to the north and wave lengths are 100 to 200 km. The most energetic waves occur in the 8 to 12 day period band. Downstream velocities seem to be coherent in the lower layer across the entire Florida Straits in this period band and downstream coherence scales are about 50 to 100 km. Offshore meanders are associated with the formation of cyclonic, cold-core frontal eddies, deep flow reversals, decreased transports on the cyclonic side of the current, increased transport on the anticyclonic side, and increased total transport. Onshore meanders are accompanied by increased northward transport in the cyclonic zone, Page 10 decreased transport in the anticyclonic zone and decreased total transport. Growing meanders of this type appear to derive their energy from the potential energy of the mean Florida Current then convert the. energy back to the mean state through transfer of perturbation kinetic energy, with no substantial net energy conversion on the cross-sectional average. This internal energy readjustment appears to be more active within the cyclonic shear zone and could be connected to a baroclinic instability process. Fluctuations. of this type have a significant impact on fluxes of mass, heat and momentum through the Florida Straits and to the adjacent water masses. Tidal Variability Current and transport fluctuations in the tidal/inertial period band account for approximately 10 to 20% of the observed total variability (Schmitz and Richardson, 1968; Kielman and DUing, 1974; Mooers and Brooks, 1977; Brooks, 1979). Both diurnal (Ki. 0 1) and semi-diurnal (M 2, S 2) periods occur and produce transport fluctuations 6 3 -1 with amplitudes of +3 to 4 x 10 m S Smith, Zetler.and Broida (1969) and Zetler and Hansen (1970) hypothesized that since tidal sea level variations in the Florida Straits were primarily semi-diurnal then the observed diurnal component of the flow is produced by a standing wave with a node near Miami. -Amplitudes of the K 1 and 0 1 components of downstream currents or transport were found to be greater than or equal to the M 2 component (Schmitz and Richardson, 1968; Smith et al., 1969; Kielman and DUing, 1974; Brooks, 1979). Energy spectra of downstream (v) and cross-stream (u) velocity components from the lower layer over VI Page 11 the Miami Terrace clearly show larger variance for the diurnal fluctuations (Fig. 11, from Kielman and Wing, 1974). The 0 1 constituent was largest for the v component and K 1 was greatest u tidal constituent. The downstream component accounted for about 25% of the total variance and 6% for the cross-stream component. The harmonic constants (amplitude and phase for Ki. Olp M 2 and S2 computed from surface current speed records (Smith et al., 1969) were found to agree well with those computed for lower layer currents by Kielman and Ming, indicating a strong barotropic structure to the tides. Spectra of the "detailed" velocity components, i.e., after subtracting the tidal components determined by harmonic analysis (Fig. 11) show a considerable reduction (by almost an order of magnitude) in the downstream component both at diurnal-inertial and semi-diurnal periods. Brooks (1979) used a Munk/Cartwright technique to remove the tidal signal from station transport data and found little effect. However, the small changes at each station accumulated to produce a large effect on the total transport through the section. Brooks reported that the semi-diurnal and diurnal tides accounted for about 20% of the total variance. The diurnal component produced most of the tidal variance over the Miami Terrace and near the Bahama Bank and the semi-diurnal component had a larger effect in the interior of the Current. The phase of the diurnal component was relatively constant between Miami and the Bahamas, again indicating a standing wave with a node near Miami. Mooers and Brooks (1977) analyzed thermistor arrays and tide gauge records from sides of the Florida Current. They found appreciable diurnal and semi-diurnal internal tidal energy that was as large as the log ENERGY SPECTRUM V-COMPONENT 106 Sol 10- BANOWIDTH: *--e 0.157cod. 90% CONFIDENCE- .100 cc 101 01 ME ice 0 1.0 2.0 3.0 4.0 cpd 5.0 tot 120 2.4 9 6 -PER100 W 10, ENERGY SPECTRUM U-COMPONENT 104 BANDWIDTH: 0.157 cPd. 90 % CON FIDENCE: :,Of t I MR cc lot W lop 0 1.0 20 3,0 40 Cod- 5.0 Fig. 11. Ifigh-frequency spectra of north-south and east-west components (solid lines) and spectra of residuals after removal of ti dal oscillations KI, 01, N12, S2 (dashed K lines) (from Fig. 7, Kielmann and Duing, 19/4). Page 12 surface tides. The diurnal internal tide was dominant. Near- inertial motions were apparent at depths at the effective inertial frequency which varied as a function of horizontal shear (20 hours near Miami and 35 hours near Bimini). They found that low-frequency fluctuations can modulate all near-inertial motions including diurnal and semi-diurnal internal tides causing time-varying amplitudes. The modulation time scale was monthly and longer for the diurnal internal tides and fortnightly and longer for the semi-diurnal internal tides. Mooers and Brooks also found that the cross-channel phase of the diurnal and semi-diurnal internal tides indicated that internal seiches could exist in the Florida Straits at these periods. Loop Current Circulation in the eastern Gulf of Mexico is dominated by the Loop Current, the portion of the Gulf Stream which connects the Yucatan Current to the Florida Current (Cochrane, 1972; Nowlin and Hubertz, 1972). Its water originates in the North Atlantic Equatorial Zone and is transported to the area via the Caribbean Sea and the Straits of Yucatan. Af ter penetrating the Gulf, the current pattern arcs anticyclonically (clockwise) to the east and southeast, forming a current "Loop" which subsequently exits through the Florida Straits. The western and eastern boundaries of the Loop are fixed by topography of the basin (eastern Gulf)(Cochrane, 1972). In the Loop, interior flow is also anticyclonic. The flow pattern is elongated along an axis parallel to the shelf regions on either side and centered over the deep basin (Cochrane, 1972). Some portion of the Page 13 southern Loop flow may exit back through the Straits of Yucatan rather than the Florida Straits (Nowlin, 1971). This portion varies, depending upon the degree of are in the Loop pattern, or as a lower layer return flow (Maul, 1977). The Loop Current influences flow to a depth of greater than 1000 m (Nowlin, 1971). As would be expected, current velocities decrease with increasing depth from a maximum of about 100 cm s- I at the surface. Numerous estimates of transport in the Loop Current have been made using various techniques. An average value of 30 x 10 6m3s-I has been determined by Nowlin and Hubertz (1972), Nowlin and McLellan (1969), Schmitz and Richardson (1968), and Morrison and Nowlin (1977), although their reference levels are not necessarily directly. analogous. Values for inflow and outflow of 22.3 and 21.4 x 10 6m3 s-1 were determined by Molinari and Yager (1977) and Brooks and Niiler (1975), respectively. Studies of the Loop Current have shown that it is a highly variable, complex system. A comparison of the extent of the northward intrusion of the Loop as observed by different investigators indicates that the spatial extremes of 1) direct flow from the Yucatan Straits to the Florida Strai ts and 2) intrusion of the Loop as far north as 28.5 0 are both relatively common. Leipper (1967,. 1970) proposed an annual cycle of growth and decay of the Loop Current, beginning with the formation of a small Loop near Cuba in January- February and subsequent growth into the Gulf through August. He termed the sequence the "spring intrusion". The decay phase follows with a general weakening of the -Loop and splitting of the flow, either in detached eddies, current rings, or extension to the west. 3d 0 .0 2e .04111 TORTU"S KE ST HABANA 21 U VL)CATAId' KNINSULA jeC AT 100 METERS ge so, se Ge be Fig. 12. Compilation of pathlines of the 22 0 C isotherm at 100 m depth from August, 1972 through September, 1973. Where the indicator isotherm intersected the bottom topography, a dashed line is used to estimate its position from the other thermal data. Where the cruise started in 1 month and ended in another, both months are indicated. 100 m isobath is indicated by a dash-dot line and represents very closely the shelf break and escarpment zone (from Maul, 1977). Page 14 Maul (1977) studied the annual cycle of the Loop Current between August, 1972 and September, 1973, and concluded that, although the pattern is cyclic, year-to-year variability is significant and that the "intrusion" (Leipper, 1970) is not necessarily a spring phenomenon. Fig. 12 shows the path lines of the 22 0C isotherm determined in his work. They demonstrate a maximum intrusion to 28 045'N in August, 1973 and a minimum to 24 015'N in December, 1972. As the Loop penetrated deeper into the Gulf, it also moved further to the west (Maul, 1977). Growth of the Loop in the Gulf is believed to result from an excess of inflow through the Yucatan Straits over outflow through Florida Straits (Leipper, 1967; Maul, 1977). Maul (1977) calculated that a net 6 3 -1 flow increase of 4 x 10 m s _ was required to induce growth. The flow increase through the Yucatan area may be associated with seasonal increase in transport of the Florida Current. The detachment of large, anticyclonic eddies from the Loop Current is well documented (Nowlin, Hubertz and Reid, 1968; Leipper, 1970; Leipper, Cochrane and Hewitt, 19.72; Morrison and Nowlin, 1977; Cochrane, 1972). These features exhibi*i a range of surface current speeds up to a maximum comparable to that observed within the main Loop Current (about 100 cm s- The formation of these eddies is believed to occur on an average of once per year, normally following the intrusion of the Loop north into the Gulf. Hurlburt and Thompson (1982) used numerical model experiments to show that the quasi-annual eddy shedding period could be TEMPERATURE (*C) z CD cn or 0 0810 0 0@ --- vi 0 0 09 at 00 888 4M 0- 0 CO C+ 0 4h 8 Cd %X 0 iM cr V03- @2 '0 Page 16 of interior Florida is classified as wet subtropical becaus e the impact of the warm Florida Current is less significant. The mean annual air temperature near the Straits is 23.9 0C, with July-August the hottest months (average high of 29.2 0C) and December-January the coldest (average low of 15.80C). An upper air trough centered over south Florida gives rise to a rainy season during the months of June and September. The wet season abates somewhat in July and August because the trough moves west out over the Gulf of Mexico during that period. It returns by September. The entire rainy season may span May through November. January and February are the driest months. Average annual rainfall is approximately 160 cm. South Florida lies at the northern end of the trade wind belt (easterlies) throughout most of the year. Resultant summer winds are commonly out of the southeast. In the winter, the easterly trades are interrupted by the transient occurrence of cold fronts on time scales of about one week (Fernandez-Partagas and Mooers, 1976). During a cold front, winds cycle in a clockwise direction and intensify to 10 m s- I or more. Diurnal variations of the trade winds are common, especially in summer; winds often become light and variable at nightfall. Hurricanes Tropical cyclones occasionally affect the Florida Straits region. j Similar to Pacific typhoons, Atlantic hurricanes occur seasonally, Page 17 generally between June and November. Most hurricanes originate as a tropical disturbance in the equatorial Atlantic, attaining hurricane strength in the Atlantic Caribbean or Gulf of Mexico. South Florida coasts are affected by hurricanes more often than any other equal-sized area of the United States (see Gentry, 1974). Based on data for the past 100 years, the probability that hurricanes with winds greater than Ill kph will hit the Miami-Ft. Lauderdale coastline is 15% per year; the probability of a great hurricane (>201 kph) is 7% per year. September and October are the most active months, 62% of all hurricanes occurring then. The south Florida area has averaged about one hurricane every two years for the period since 1885. Hurricane winds are capable of producing extremely largewaves. As an example, a 15.24 m, 10 second period wave was recorded at 27 0 01'N, 79051'W (off Hollywood, FL.) in 317 m of water during Hurricane Betsey in 1965. Page 18 3) Current and Temperature Profile Data A total of 28 profiles of temperature, current speed and direction were recorded during three anchor stations 1, 11 and III which each last approximately 24 hours(see locator map Fig. 14). From the historical data (see section 2) it is well known that considerable current variability exists at the diurnal and semidiurnal tidal periods. By recording over a 24 hour period we can estimate the slowly varying mean current profile and its standard deviation. The times of each profile and wind data are shown in figure 15. Current profiles were recorded using a FB-II profiling hull with an Aanderaa current meter as described by Ming and Johnson (1972). The R/V Bellows was first anchored at each proposed OTEC site in 700 to 800 meters of water, respectively using a scope of about 2 to 1 with a large Danforth type anchor, 100 feet of 3/4" chain and 1/2 trawl wire deployed over a bow roller. Once Loran C fixes showed a steady position, the hydro wire was lowered over the "A frame" on the starboard side with a 500 pound weight to minimize wire angle. This weight was then lowered to within 10 to 30 meters of the bottom. Finally the profiler was attached to the wire by means of its roller and permitted to free fall down the hydro wire until it encountered the bottom stop. Ballasting and horizontal trim of . the prof i ler was checked in a tank at RSMAS and monitored using the Precision Depth Recorder (PDR). When the PDR trace confirmed that the profiler had arrived at the bottom, the hydro wire was winched in until the profiler was once again at the surface. A line secured the profiler at the surface while the weight was lowered to the bottom ready for the next profile to begin. Figure 16 f rom DUing and 82@W F RIDA Lo V @y S a ANK AL KE KF WFST <V lF'T -,ps SITING 3"' 600' REGION 2 SITING REGION 1 3000 FT 24ON CAYSALBANK APPROXIMATE AXIS OF FLORIDA CURRENT 0 600 FT 0 10 20 30 L -j L SCALE IN NAUTICAL MI LES OHABANA I CUOA I Figure 14: Locator map showing prospective FOTEC sites. Stations I and III were made.at site 1 while.Station II was made at site 1. KEy E @W STATION NO. PROFILE NO. DATE --- TIME WIND SPEED WIND DIRECTION (DEGREES M) @O @S- 2/1?/e3 16glO 0 TO .7 VARIABLE 2 2/':L9/e3 18:30 2 TO 3 190 o --- 2/19/83 221 - 3 3 TO I C-) 4 2/20/93 00:35 8 25 5 2 / 21 0 / 8:3 03.00 12 1. 2 5 6 2/20/83 05:16 10 TO 12: 112 2/20/83 07: 52 1 c) To 1 :2 90 2/20/e3 lo:19 5 To a 50 I IN P ORT 9 STRONG WINDS 2/'20/83 12:4e 5 TO 8 90 11 .10 -:*_/23/e3 05g45 6 TO 8 29o 11 11 2 /2 -3 / a 3 2 0 " 0 0 6 TO 8 340 ii 2/2@:'/83 22:15 4 TO 6 330 1 .3. .'2. / 2. 4 / 8 3 0 1 - 2 C.) 5 To B 32o 11 14 2/124/8.--:" 02.47 4 TO 6 --oo II J. 5 2/24/83 05" . 10 3 TO 5 ',-'-'5 0 11 16 2/24/83 07."15 4 TO 6 270 11 17 2/24/83 o9:37 10 TO 12 251 11 . --- 'is - - .. 21241e'-'--l'e.:'. 15 10 TO 13 264 11 19 2 / 2`4 / 8 3 14:43 6 To 8 272 II --:,C) @/@4/83 17: 07 4 TO 6 247 MOVE TO NEXT STATION* 111 21 22/25/83 06: 54 lo T L-) 15 :320 /275 / 8 ---r (-)9.. 12 TO 15 2/-5/83 12: Qe 10 TO 15 34C) 4 2/25/83 15:45 (3 TO 1 C-) 34C) 25 2/25/83 18:22- 12 TO 1 '13 26 2:)/25/83 2 1: 06 15 5 27 2/23/8-@- 2@ 3 : 3. C) 15 TO 17 5 2/26/83 0 1. 45 15 50 2. INSTRUMENT AND METHODS Principle. Figure I shows the pri nciple of the profiling method. The profilcr (Fig. 2) consists of a ,elf-contained Aanderaa current meter (AANDERAA, 1964; DAIII., 1969) attached to a cylindrical hull. I he density of the instrument package is slightly greater than that of the surrounding water. The &i%onius rotor extends out from the bottom side of the cylindrical hull when it is in its horizontal work-ing position. The entire package is attached by a roller to a taut wire susp--nded beneath the anchored ship and allowed to descend slowly through the entire water column. AANDERAA RECORDER: T,S,p,V Y (0) PVC HOUSING C-C) GLASS SPHERES FOR FLOTATION (D) -(RIM BAR ROLLER A B .0 D Fig. 1. Principle of current profiling method used in the Florida Current. Figure 16: Principle of current profiling method used in the Florida Current (from Duing and Johnson, 1972). Page 20 a) Mean Curren t Profiles The mean current profiles for the three anchor stations as seen in figures I-M, II-M, III-M are remarkably similar to each other in the upper 100 meters. Here velocities were about 75 cm per sec toward the East with a Northerly component of 10-15 cm s- At 100 meters there was a distinct break in the velocity which coincided with a break in the temperature profile from a relic mixed layer structure with modest stratification to the top of a strong thermocline. Below 100 meters both velocity components decreased toward smaller velocities being about a half of the surface amplitude at 200 meters with a more gradual decrease toward + 5 cm s -1 near the bottom. b) Standard Deviations from the Mean Velocity Profiles The standard deviations of the individual profiles from the one day average profiles as seen in figures I-SD, II-SD$ III-SD show their largest values near the surface. Typical values near the surface are 15 -1 -I cm s while values below 200 meters are order 5 cm s The extreme value occurred at Station 2 at the surface of about 40 cm s- 1 as a reversal of the velocity deviation near the end of the record with peak velocities over 150 cm s- 1. These strong short lived velocities may represent a transient response of the surface layers to westerly wind forcing. c) Mean Temperature Profiles mean temperature profiles are also seen in Fig. I-M, II-M, and III-M. Near bottom temperatures stayed in a narrow range near 7 0C while 0 near surface temperatures varied in a range of 23 +1 C. Most of the near surface temperatures were nearer 24 0C so that a mean temperature 6 T T 3 MERN 1 00 200' 3.0 0 E 400-, T 5 j 0 H., ZMETER3@ 600-11 ir 0 C E.L S I LIS @'@Ol 24 0 c m S C @75 75 5 C', Z--Ef 5 o u cm S. EC. 7 5 0 11 5 05 22 5 3010 W r e on e LONG= t-) 1. 983 R -240 0683 1411 DRTE MERN STR.TIQN:---2 --230283 T ME.054 0 to J, 0:0 H" -ME4 t9s) 7 -0 0 24 21 30@ '0' .7 5- -2 0-0 U, 2@0 v 0, 2-2 5- IM s T R N D 'ON: 1 DRi.E:200-' 3 1001 200, + 13 0 0 E 400 P, T 500- H. 11 EE R S . ....- -600 7` 700 C E L S I US) 0 0.5 1.5 -2.o 2,5 T 4 0 -10 c @111 I E C 0 20, 40 50 U fL7, v Qim l/.S c 0 10 20 0 50 9 L P. 2z@ 0 6 8-1 I-SD F- ---cS-Tl-'R-ND--DEV @')TRTI DRTE:240'83 TIME:O? ON., 2 .100 0 0 3 0 0-ii 4 Ol 0 p T 500 + + H 'TERS' 600 0 cl@ 8 0 OL E L S TIJ 0 0.6 c @@i s IE C- 0 2 0-1 30 40 50. U 40 50 V C m 3 E C, 0 10 2 C, 30 214 0 17 L 0 N G -8 1 1983 @ A-V ii-so T M 7 2 3 D R T _E 2 -5 0 6 3 T 'E_ C4, D_ T P, T N 0 OL 0 ".jj I Tr. I 'T 4 20, "D p 5 0 4 3,'; , X H A H E R S 01.0 El 700 P2. C S T J 0 0." 2, 25 0 0 22, .50 0 cm 0 10 0 4 Ol so V@ L ON , 07 5.0, 'D 7 I -SD Page 21 difference on all three anchor stations was near 170C. February is usually near the minimum temperature for the year so this should represent a worst case. In the upper 100 meters there is some evidence of step structure in the mean temperature profiles while below this depth a smooth monitonically dec:reasing temperature is seen. Although in winter there may be a iocal subsurface temperature maximum stabilized by correspondingly higher tropical salinities. Individual profiles show numerous local inversions of this type on the 10-50 meter vertical scale. However, no such inversions were observed in the mean profiler. 3.4) Standard Deviations about the Mean Temperature Profiles 'As expected the largest standard deviations from the mean temperature profiles occurred where the vertical temperature gradient was largest. For the lower portions of the profile the standard deviations were less than a ten*th of a degree C. However, near the surface typical values increa sed to .50C with extreme values of 1.50C. 7' T F I L FE 1 of'TR'IQN: I S@T@::-: 19028 -11E: 1610 100- ir + 0 Oi -3100 D 0 10 P + H T, -@4 6001 .700- 4- 4- + F3 001 s I 'Lis0 6 30 12 24 M S LE C-75 10 75 5 0 225 300 U 0 0 V C M S 'E- C 7 5 0 7 1 C:o re ong e= 7 L 2- 4 0 6 8 LONG= -8 1 9983 IPTLE12 STRTLON: D R T E 1 0 2 S) 3 1 Iv I E18 3 2 0 0[ 4- D '00 itz- 4-0 0 4- p OOL (MEETEERS) 00- .7 0 0 o c E, L -5 -1s 0 6 -1-2 2') 4 30, -T -150 C I v ISD-E C 75 310.0 u m S) 'C' 7 EIS 0 50 2 2-5 d o .2j r e c n e L.R T@; 9 1-2 T T E `31 S TIR Ty ON. R T F19 0 23 1 M -1-3 :---1 L @v 10 2 0' 0 0 E 40oL p I T 5 0 00@ H (METER3) 6 0 0 J 700 .. . . . .. . . ... 8 OL C STUS 0 EL 6 12 18 24 30 T CIM/SEC -75 0 75 15 0 225 0 0 u C M S E C7 -57 7 1-50 ?25 re ong e= 6 LRT= 2 0683 L 0 @,-l G-81.9983 P-3 FII.FI4 QTRT,T (ION- 1, "-0038 DRTE: 2.. -2,9 i MP. lool 20,01 D 3 0 4- E p T -5001 H (METERS) 600L -4- 700 8 0 30 T "-LS I US 0 12 18 2 4 c S E, C,- i 5 0 1 1 Z5 CA 22 5 300 U 'CM cS E C - 7 Sj Ol 5 0 8 0 ol, V pri -@VIV L P, T 0 11 Q LONG I @Jj 1-4 T FILE15 STRTION- 1 D T E 2 0 02- 8,3.TM E0 2 4 6 1001, v 2 0 112@- 4- 1 + D @7 400- p T 500- H (METERS> 600@ 700- 8001 ICELSIUS 0 6 12 18 24 30. T CM/ISEC - 7 0 75 150 225 '3 0 0U Cm/sEC _715 0 75 150 2 e2- 5 31qo* v .7 r e ong e:z V 4. 0 6 83" L 0 N'G -81.9933 7 T 0 8 3 M F 0 F i L -TRITtION". I., D IT E 2 513 .10 q-, 2 0 0i 4@ 4- D 300 4001 p @T 5 0 0@- + H (METER3) 600r 700L 8 0 O@- CEL SIUS 0 12 18 30 C M S E C - 7 5) 0 75 5 0 225 - 300 U c M 'S E 7 0 75 150 225 @,3) 0 0 N' 1 r e on.-) e= L R, T 2 4 0 6 8 LONG= 81 Q/983 FILE17 STRTION: I DRTE:200288 TIME:0751 100- 20 D 300- + E 400- + p T 500- METERS) (ID 0 0 700- + 7Z-.. .8 @O 0 =6 CELSIUS 0 .6 12 18 24 30. T cM/SEC -75 0 .75 1.50 2 2.5. 300--. CM/-SEC -775 0 75 150 225@ 300 -V @Wire ongle= 0 LRT- 24.0683. LONG= .-81.9983 FILE18 STRTION".. j DRTE:200283 TIME:1018- too- + 200- D 300- E 400- p T 500- (METERS) 6.0.0 700- 800 =6 CELSIUS 0 -6 12 18 24: 30'. CM/SEC -75 .0 75 150 225 7300 U CM/SEC -75 0 75 150 2 2 5 300 v W r e ang I e= 0 LAT"-_ -24N'0688 LO-NG=-.-,81.9983 1-8 F I L E 19 S T R TON.- I DRTE:20028-3 ;IME:1248 100- 4- 2 0 -D 300- E 400 4- p -T @500- + H IMITII81 600- 4- + + .700- 8 o of--= =k CELS I US .6 12 18 24 .310 T CM/SEC -75 -75 150 225 -300., U CM/SEC -75 0 7 150 225 .300 v Hire ongle= -5 LR T 24.0683 LONG= .-81.9983 FILE21 'S'IA,,TION,,:2 DHTE:230283 TJME-.0545 too- 4- 4- 2001 D 300- .E 400- + p -T 500- + 4@ H (METERS) 600- @7 0 0 + C E L S I U S01 6 1. 2 1.8 :24 30 -'T C'.M-I/SEC .-75D 0 150 225 300'. u Cm/sEC-1-75 0' .7 5 150 225 300 v Wire ong I e- 7 LFIT= 24.1950 LCING* 81-1983 Tj ME FILE22 STRTIOR: 2 DRTE:230283 0758 "..100 2 0 0 D @300- @E .400- p T 500- -H m RS3 600 4- .00 .8 0 0 0 '24 3 CELSIUS 0. 6 1111- 18 75 50 0 0 CM/SEC. 0 75- E7 CM/3EC 75 7%.) 1.50 225' 3 0 0 W i.r'e' ang I e- 6-- LAT=: 24. 1950 LONG---; -81. 1983 11-2 --S-T@R-Tti-N 02-a- .-A-01.3 z-@ T --ME F.-I-L E 2 8 2: -D--RT E @--2-a 100 -200- Ell D 300. E 400- P. 7% 500 + _H. (METERS) --6.00, 4 7 7 0 0 f8o ..T .-30- 12 18- -2 4 CELSIUS 0 @:_7, 'o 0 ._75 CM/SEC 7S .300, @;v 0 2 5 5 S C@ 7 5 c m Wir e.anb 1 17 _@if 24 a 4 19-83 LH I 11-3 FILE24 STPTI.ON' .2 DRT-E-23.0283 TIME:1240 too- + ;+ 200k D 300- + E 400- p T 500 H (METERS) 600- 70 0 + .4@ 30, '.,-...T CELSIUS 0 6 12 1. 8 24 225 U tCM/SEC -@75 -.75 CM/SEC -75 t..0 225. .3-00v W i"re ong I ia= 'I'L RT= 24. 1983 --LONG= -81 2 0 T R -7 F -I- L- LE 2,5; IV T 1-0 N -3@0 2 8 9 T [email protected] I-E 1'4 4 100-" + zoo- + 31 0 0 D + E - 40-0 + -T .500-1 T (METERS)- --6 0 OL + 70,op 0 0 3-0 T C, E -L S,-I jJ S,* 0, 6 -2z: 300- U L-M -7-5 0 5 z t 41 S. E - C-75-- .0- -15-0- 225 0 0 V, r e* c n @e c L R-T-j= 2-00Z, L.0,N &,-- 'l-U-3- 11-5 FILE26 STRTION: 2 .:l,-DRTE:230283 TIME:1710 loo .200, @300 E w". .400 + + p T coo H (METERS) 6 0 0 + + 700 8 0 0 CELSIUS 6 12 8 24, 30 -T J'%2 2 5 t'o Cm/SEC 75 0., 7 5-. 300 u 3 00 V CM/SEC --751- 0. 75.-' .50 2 25 W !'re a n g 8 L T 2k.'-2000 LONG= _8 1 198@1...*... R 11-6 F-I L--E---.?-7- S-TRT -4 ---,@2- -----D. R T E:-,.@ 2-3- 0-2 8 3 - T. M E. t-oo: 0 0 30.0, E 74-:. 4' .5 H (METERSO)@@ @-60-0 1-7 lz 0 . Eq 0 0. C E-L STIJS Y-2 /-2,4 -33; 0 18 ."75 -2 25 -300 U -C M S DC" J., 0 5 0 77 -300 @.,,V c 75 -2-2-5 14 0 T - Page 20 -iwL) mean current Profiles The mean current profiles for the three anchor stations as seen in figures I-M, II-M, III-M are remarkably similar to each other in the upper 100 meters. Here velocities were about 75 cm, per sec toward the East with a Northerly component of 10-15 cm s-1 . At 100 meters there was a distinct break in the velocity which coincided with a break in the temperature profile from a relic mixed layer structure with modest stratification to the top of a strong thermocline. Below 100 meters both velocity components decreased toward smaller velocities being about a half of the surface amplitude at 200 meters with a more gradual decrease toward + 5 cm s near the bottom. Standard Deviations from the Mean Velocity Profiles The standard deviations of the individual profiles from the one day average profiles as seen in figures I-SD, II-SD, III-SD show their largest values near the surface. Typical values near the surface are 15 1 cm s-1 while values below 200 meters are order 5 cm s- . .The extreme value occurred at Station 2 at the surface of about 40 cm s-1 as a reversal of the velocity deviation near the end of the record with peak velocities over 150- cm s These strong short lived velocities may represent a transient response of the surface layers to westerly wind forcing. Mean Temperature Profiles Mean temperature profiles are also seen in Fig. I-M, II-M, and III-M. Near bottom temperatures stayed in a narrow range near 7 0C while near surface temperatures varied in a range of 23 +1 0C. Most of the near surface temperatures were nearer 24 0 C so that a mean temperature FILE28 STRTION;, 2 D,RTE--: 23OL83 T ME: 2 138 4 D 300- E vi P. -:@5 0 0 H M E T E R!1-2 i I e -tra I u Q@,? -e n are c r d c r 5 cm @t cc, @,7 0,- in '8:0 0 T 2 C E L S I @JS7 -0' 30 T u 2 5 800. CM/SE&- 7.5 0 75 150 2 - - 225 30 0 V C M S, E -'C", 5' 0 75 150 21 W e a r f 2,0 lt7m a r a m e al - te-upara :@v.-,-- LRT= n' 2-,'--4' FILE29 STRTIO@J:'2 TI@IE:'0016 -100-- + 200- + D 300 E 500 H (METERS). '@600- -70,0- .80oL .1 3'0 CELSIUS '0 6 12 .18 ..24. C IM /SEC. @'75 0 75 5 2 2 5 50 0 U 225,- -:.30 CM/SEC 75* 0 75. 1.50 0. V. W re o n' e , LRT=. 2 4,; 2 0 17 LONG= 7. 8.19 1983 fi-9 ---F I L E H. --2- -D,-RT-E-;--2.4-02 8 3;-1J0227- 100- + 200 D 500 E- 400- 00 (METERS)', -4 600- 7 0 0 800 k_- -3-0 -.-.-T C E L 5 1 V5-- qoo Uf.' WSEC -5 5 15 0 -75 0 75" 5 300V CM/SEC re p, e7-7 LB"T=- 24. M77 LONG 84 19 -240288 F.PE02 STATION:,O DATE,; T'ME-.0452 too- 200- to 30 D E 400- P T 500- + H (METERS) 6 0 0- 700- 8 01 Oi== 2 4 30: @T CELSIUS 12 -18 C MIS E C-75 0 75 .150 300 7.5 :'2 2 5 300 C MS E C' -75 0 @Wi re ang I e- --l ? ILRT= 2 4, 2 0 17 L'O N G--81 19 8 3 FILE31 STATIQ@: 3 DATE:250283 TI@IE:0654 100- + 300- E 400- p T .500 H (METERS) 600 800 6 CELSIUS 0 6 1-2 18 30 T Cm/SEC -75 0 @A 50' 225 300 U .75 CM/SEC, -.75 0 75 'l 50 --225 3'0 0 re o.n.g e.=.' .24.0800 LONG= -81.9900 0 N ME.-b. 09-3 2 FILE32 S.TP. 2.5.0283 -T ' TJ ORTE. 00- + + + 2 0'0 + + 3 H E .4400- v -Z@500 4@ (KETERS) 00- rA 7-00 .7a .01 0 z-2-4 30 -S: T US @@o -2 'CE L- -2 -7,5 I--7ETO -2:5 @300 uf C M,-/--S E -C --7- ;7-5 t5 0 2," Z 8,00 7 -01 JII-2 3 _:ST -,:D RT --T IM E: 12 0 6 -101j., 3 -1250283 F I-L E 8 RT E. r,l-.o 0 2.00 300- + D E 4010 p -T 5H- @H. <F.ETER3) 600- + + -700 8 0 -4= --T C E L S I US --,0- ----@6 LIS C,Pl@ 0 -300 U CM/SEC -75 2 2f, 5 0 0. 2,2-5 Zy -V -'C mS E 7.7-5 -75 1,-5 0 re ong e 1-8 .2:4 LRT @0-0 18"1 -19r9--(a:o 111-3 FILE34-"STAT DRTE:250283 TLME:1542 ION, 100- 4- 200@ D 300- + E p T 500 H (METERS) @600- + 700 8 0 or__- CELSIUS 0 :'6 . 12 48 24 30 T A 225 300 U CM/SEC -75 -0 75 -50 -150 225 300 V CM/SEC -75 0 7.5 Wire ong I e= LRT- --24.0800 LONG= 9900 111-4 FjLE35,,STRTI'O.N:.-A-- -DR7E-:@250283-ITI ME.-*18-118 100 200- + + Dl- 4.0--0 pr- -7T7 50 0 (M@IERS) I- A 7,00 71_ 8LO 01= A'L =6 3:0 T C'E S 0-,* -7 00., Ll 22 -.5 -5 1 5@ .0. O;L@ 7: 300 V _O@ T;; 7E@ 2-41 8 -------- f-5 'FILE36 STRTIqN,. 3 DATE-.250283 TJME:2031 'too- 4- .200 .4- .4- 300 E 400- + p T 5 00 + H (METERS) 600 + -700-- .8 0 4@- =6 =1= 18 24 30 T CELSIUS .0 6 12 Cm/SEC 7 5' 0 75 -1.50 .225 300@ U C@'.-,/SEC -75. .0 75 150, :300 N [r e on 7 LRT= 24.-0800 LONG= -81.9900 I.-L -E-3 T; S T Q -N -3' ..-DRT,E 25.02.83. 7-j-ME-.2-2-51 .100- 200-@ D 5-0 0-- E -400- . p T 0 0 @pH .(METERS3 0.0 -;7 0 0 & 0 `0 P= -J. 10 'Us@ 1-2 1@ 8 --'3 0 T' CELSL 6 -.24 C M S E C 7 5 0 75 t-50 --225 '"300 L) '2 330 0 V :-CM/SEC--@f75 0 -775 5, 0 25 o n. g J, 6 T 2A 1@1107 50 0 X C--' 1,81 .n t 7 111-7- FILE38 STRTION,.- 3 DRTE:,2602-8-i TIME:0106 200- + D 300- + E 400- P'. + + T 500- H (METERS) :60 0 -.800= =6 =6 :1 CELSIUS 0 6 12 -.18. 24 30 T C M S'E CC --75 7 51 50 2 2 5 300 Cm/SEC -75 0. 75 150 300 v w r eong I e= 24.0750 LONG= -81.9917 LR IH-8 Page 22 4) Temperature Section Data Before or after each profile anchor station, a temperature section was recorded which passed through the approximate location of the anchor station as., seen in Fig. 17 and were roughly normal to the bathymetric contours. These sections give some idea about context in which the anchor station was occupied and. make it possible to relate the anchor station data to both historic data and remotely sensed surface temperature data. The temperature data were observed using Expendable. Bathythermograph (XBT) probes (T-5) manufactured by Sippican Corporation in Marion, Massachusetts. The XBT is a temperature profiling system which senses temperature with a thermistor and relates -the nearly constant fall velocity of a weighted streamlined housing to depth as described by Williams (1973). Unlike hydrographic stations the ship can continue moving as the XBT unspools wire from both ends in much the same way that line is released from a fisherman's spinning reel. The XBT data were finally recorded on a pressure sensitive constant speed strip chart to display a temperature profile. XBT recorded temperatures are accurate to about +.05 0C and depths +20 meters. The temperature data from each XBT drop was plotted at I C intervals at the appropriate geographic spacing to form each section. The sloping piecewise linear line at the bottom depths observed at each XBT station by PDR. Inflection points indicate each XBT location and the number below denotes the station location and order as seen on Figs. 18, 19, and 20. Hydrographic data were also gathered at both ends of each section Section I Section II Section III 24020 5 6 14 24010 2M 13 N 7 12 9 24000 3 11 4@D 23050 L- 10 8201OW 82000 81050 8102OW 81010 81000 8201OW 82000 81050 n, LOC. WHERE PCM STATIONS 0 HYDROCAST F)XBT Figure 17: Location maps for section data below. XBT station numbers correspond to those in figures 18, 19, and 20. The location where the PCM stations also correspond to the A's on these respective figures. @7 8 -20 200 15 400 15 10 600 800- .................. W 1000 5 1200- 1400- 16001 X1 X2 A X3 X4 N S Figure 18: Section I shows contours of XBT temperature data in degrees C. Locations of XBT drops Xl, X2, X3 and X4 are shown together with anchor station I at A. 200 5 10 400 . . . . .... 70 .............. ......... . 600 ........ .. ................. E 800- .... ......... .... .. . ...... ............ 1000 ................. 1200 1400 1600, X5 X 6 A X7 X8 Figure 19: Section II shows contours of XBT temperature data in degrees C. Loca- tions of XBT drops X5, X6, X7 and X8 are shown together with anchor station II at A. 200 400 600 .... . ......... ... !:: .......... ..... ..... ....... ..... ... .... 800- . .. ......... .. ..... .. ................. ............. ......... .. ....... . .. .. ........... 1000- .............. ............ 1200- ........... 1400- 1600 X14 X13 X12 x1l X10 N. A S Figure 20: Section III shows contours of XBT temperature data in degrees C. Locations of XBT drops x1o, x1l, x12, X13 and X14 are shown together with anchor station III at A. 15 Page 11 using Niskin bottles with reversing thermometers. However the great difference in depth between in the inshore and offshore ends of the section, the complexity of the intervening temperature structure and the low vertical resolution made geostrophic calculations unreliable. These data are given in Table I and will not be discussed further. DESIRED 1 2 THERMOMETRIC WIRE WIRE DEPTH By DEPTH P P U DEPTH OUT ANGLE WIRE ANGLE SALINITY Cast #1 24* 13.67 820 01.52 2/18/83 0245 (GMT) 5 22.12 22.11 5 50 5 36.2626 100 19.10 19.10 100 50 95 - 350 13.29 13.19 14.15 87(?) 350 50 345 36.2641 500 - - - - 500 50 495 35.0188 Cast #2 230 53.74 810 59.68 2/19/83 0810 (GMT) 5 23.38 23.38 5 180 5 36.2537 250 15.62 15.62 19.69 315 250 180 238 36.0353 500 10.01 10.01 19.15 801 500 180 475 35.1946 650 7.84 7.84 12.76 400 650 180 620 34.9506 1000 5*46 5*43 12,75 582 1000 180 950 34*9813 Cast #3 240 16.89 810 13.72 2/23/83 0843 (GMT) 5 23.61 23.60 5 150 5 36.1620 50 21.99 21.99 50 150 48 36.2773 100 18.13 18.12 100 150 96 36.2591 200 14.92 200 150 192 35.9218 250 21.89 21.91(?) 250 150 240 35.5925 Cast #4 240 02.74 810 06.66 2/23/83 1230 (GMT) 5 23.91 23.91 5 400 4 36.2637 200 15.44 15.44 17.65 180 200 400 153 36.0187 500 9.95 9.94 13.66 220 500 400 383 35.0672 750 7.06 7.05 16.86 765 750 400 575 34.9391 950 4.97 4.96 18.51 1122 950 400 728 34.9255 Cast #5 -23" 53.52 810 57.35 2/26/83 0700 (GMT)- 5 24.69 24.63 5 280 4 36.0451 250 16.20 16.21 17.99 142 250 280 212 36.1255 500 9.98 10.30 13.94 295 500 280 425 35.2626 750 8.48 - 13.18 413 750 280 662 34.9326 1000 6*71 6*73 - 1000 280 850 34.8806 1250 6.72 6.71 13.26 544 1250 280 1109 34.9138 Cast #6 24* 13.83 82' 02.37 2/26/83 0115 (GMT) 5 22.45 22.45 5 80 5 35.9772 200 21.33 13.53 15.18 135 200 80 197 35.7386 300 - 12.05 14.21 190 300 80 296 35.3639 400 - 10.63 12.97 206 450 80 444 35.0505 550 7.52 7.52 12.47 411 550 80 542 34.4433 Table I: Hydrographic Data Page 24 5) Satellite Sea Surface Temperature Data Thirty-nine maps of sea surface temperature were provided by NOAA Miami Satellite Field Service Station spanning the period 3 January 1983 to 30 March 1983. During this time of year a strong temperature contrast exists between the cooler inshore waters and the warmer waters of the Gulf Stream offshore. During the late spring, summer and early fall the temperature contrast becomes too small for easy interpretations. As with all satellite IR data, intervening clouds and moisture interfere with accurate interpretation so that composite charts are drafted which include a large number of individual images spanning several days or even a week or more. This technique relies on the assumption that the position of the edge of the stream varies slowly. However the historical data in section 2 is rich in energetic motion with 4 to 10 day periods. Further questions persist about how representative surface temperatures are of the underlying temperature structure. Even with the above drawbacks these data give a good general idea of the variability to be expected in the location of the Gulf Stream within the Straits of Florida. Clearly one can see large variations in edge position from very near the keys to two thirds of the way to Cuba. Also evident are spin-off eddies as described in section 2 above. Page 14 5) Satellite Sea Surface Temperature Data Thirty-nine maps of sea surface temperature were provided by NOAA Miami Satellite Field Service Station spanning the period 3 January 1983 to 30 March 1983. During this time of year a strong temperature contrast exists between the cooler inshore waters and the warmer waters of the Gulf Stream offshore. During the late spring, summer and early fall the temperature contrast becomes too small for easy interpretations. As with all satellite IR data, intervening clouds and moisture interfere with accurate inte rpretation so that composite charts are drafted which include a large number of individual images spanning several days or even a week or more. This technique relies on the assumption that the position of the edge of the stream varies slowly. However the historical data in section 2 is rich in energetic motion with 4 to 10 day periods. Further questions persist about how representative surface temperatures are of the underlying temperature structure. Even with the above drawbacks these data give a good general idea of the variability to be expected in the location of the Gulf Stream within the Straits of Florida. Clearly one can see large variations in edge position from very near the keys to two thirds of the way to Cuba. Also evident are spin-off eddies as described in section 2 above. JEM@ FLOW.. CHART 2450 NOAA Miami SFSS GULF STREAN Date: AD3-jAU_ 19 8L3_ Depicted land should not be used for @_4gAn2, navigation. 3-,17776G W-A R M ED-APY Be)tJA1Q4L_B_Y_ Position lines are for the edges of 381607,o@ U:ZAF?7 2,iz6RA7 162AP2. warmer water. The thin Streamline is , . - I - an estimated location for the max- z2LJ@ imum current. Measured current speeds may be shown. Position based on data 0 to 2 days old. POSition based on dataJto 7 days old. .8 Position based on d a t a 8': days or more old. Mean position for month. V K v 3 ery cold -.0 Kcold M mixed 7 W worm MOD' 7 @01 .010 bilVV tO CW -@c 7'7! NEXT UPDATE.::-* 7: 7 VV. 100 2c .7-7" 2 7 S 7- '7 4 2 -79 Nd IM fLOW CHART 2450 NOAA Miami SFSS GULF STREAM D ate: Depicted land should not be used for Zila= 2W(Aap -tuWAP-10.3 a3plo/_ navigation, Position lines are for the edges of warmer water. The thin streamline is an estimated location for the max- IMUM current. Measured current speeds may be shown. Position based on data 0 to 2 days old. 47., Position based o' n data 3to 7 days old. 8.6'. Position based on data 8 daysormoreold. 30- 8 Mean Position for month. 36- V K very cold Kcold M mixed W worm % @01po .%000 28 V % S '2, NEXT UPDATE Mb MiA.- .100 fro 26 17 25 8,7 8) 79 f IftM 'FLOW CHART 2450 NOAA Miami SFSS GULF STREAM Date:O 17AN 198,2, 2-;?ZSSP 23RAfZ2 -Ijj3aaA7 .2_76'70Q 17 777 Depicted land should not be used for navigation. U -16 o 9 ot) 0 t I MD'E, P-B-Y __* Position lines are for the edges of -2 L112 8 2- 3 warmer water. The thin streamline is -3 )IZA6 6- an estimated location for the max- -Zl7j*_ 2.57AL14 Z5g?=8!V_6 z&SA-60 imum current. Measured current F speeds may be Shown. U2,884 Position based on data 0 to 2 days old. .-COS 7 Position based on data3to 7 days old. Position based on data 8.- days or more old. Mean position for 815 month. 0 V K very cold K cold M mixed W worm '29 Sol 7 % @\o Abb" 29 01 C 22@ ..... NEXT UPDATE M 'A 00 2, 25 8,7 4. 79 .2. rL%JVV LKART 2450 1 NOAA MiOmi SFSS GULF -STRE@ WD&D B Date: IOLJAM__ 19 83 268a&@_ DePicted land should not be used fQr ZkBD-.C zm z4%I*A_ navigation. PAW_koop@@@Ag_ 3L7@.@2o Z2 POsitiOn lines are for the edges of ,OAa&& warmerwater. The thin streamline is 221u@ an estimated location for the max- imum current. Measured current speeds May be shown. Position based on data 0 to --------- 2 days old. - Position based o* data3to 7 days old. Position based o n data days or more old. Mean Position for month. 7* 36, V K very cold K cold Mmi xed W worm 2.9 '7;7 0%0. 0 O\% 00 @ A % b 1% 0 *01 % !7. ..@7 *7:7" . . ...... NEXT Up ...... . DATE -7_ Y'7 4@0 .7 . .... . ...... /00 fly) 7 - ........... 9 JEM, FLOW CHART 4+ 2450,- NOAA Miami SFSS GULF STREAN Date: 19 23@= @ 2 Ai 381; 3 A!S Depicted land should not be used for navigation. ZI 7 2861, 2z IN BY Position lines are for the edges of P;0 LA M) DE - -1-1 T warmer water. The thin streamline is 2.C/AA,.;- 2671AA6 an estimated location for the max- imum current, Measured current 7-4 ZA if speeds may be shown. )-Maw Position based on data 0 to 2 days old. 3 Position based on' data3to 7days old. .86 Position based on data 8'. days or more old. 30. 3 1' Mean position for month. 30 V K very cold K cold M mixed W warm 7 '29 0 7 c 0 6*',\\ bb 1\5 .28 -01 S 7 NEXT UPDATE -26' .000 100 2( 25 _81.. 79 82 fEM.FLOW CHART 2450 NOAA Miami SFSS GULF STREAM Date: 4 Depicted land should not be used for. navigation. 31A 7 615 -W __T 210P Position lines are for the edges of ;IIq 3 749 -se)uAjb J_= warmer water. The thin streamline is an estimated location for the max- _36kCAA 1 .3,264-1 imum current. Measured current speeds may be shown. 2- R 286J/ Position based on data 0 to 2 days old. 4108. Position based on' data3to 7 days old. 3 .8.6 Position based on data,8'. days or more old. 30-. Mean position for. 8, month. 3' V K very cold ..0 K cold M mixed W warm "29 kol \Vrk V. .0 b bb 28' '30 550, @ol T - 7:' NEXT UPDATE 171 .2 6 MiA.-, 70 100 7 7: ..... ..... ...... IT 7' 7 '79 82 TEM FLOW CHART _ff 2450 NOAA Miami SFSS GULF STREAM Date: I P9L TA 14 1983 2-388 27o?l 8 2_80- Depicted land should not be used for navigation. 14 Vlo -7) Q :2716'R2 773818 2 -+ 19 Position, lines are for the edges of 339140 3q3 ,zs42s iqap!;q warmer water. The thin streamline is 2 2 q L&U an estimated location for the max- 30 7-3S_ '3+3 imum current. Measured current ZSqgo VZ3SSq5 2_q I 83(o :Z"EW speeds may be shown. 3604 2LIc)616 2LI/807 2q38p@o Position based on data 0 to 3-4466W 38o(a! 2 q6SO15 2q8803 2 days old. 3.3- ..Cos Position based on' data3to 7 days old. 7 .8 607 6 Position based on data 8-Ye days or more old. 30- Mean position for month. 30. 7: 7 V K very cold K cold 7 7 M mixed W worm 29 %No kol 46% bb 28 0 '505) 01 7. ... ..... NEXT UPDATE.'---' 9 w Eta... A., /00 26 '7- 2,5 79 .2 JEWFLOW CHART 2450 NOAA Miami SFSS GULF STREAM Date: A _19S& 2WA67 -2-494-15A3 Depicted land should not be used for .2 78AAA navigation. 9z 2-5 Position lines are for the edges of 32. Let/Pne-5 2,A n warmer water. The thin streamline is 3 Uo 7-3 (6 3(o7T an estimated location for the max- imum current. Measured current 3-BS(.130 3 1 G 6' speeds may be shown. Position based on data 0 to 2 days old. 08' Position based o' n data3to 7 8 :. 7 days old. 8.6 Position based on data 8'.... k % days or more old. 30. Mean position for month. 6- V K very cold 3 K cold M mixed 7:; - W worm 29 %01 % J() bb5 S 2 0 Zz NEXT UPDATE iA 100 26 7 7 N 2,5 79 TEM FLOW CHART Ir 2450 NOAA Miami SFSS GULF STREAM Date: 2.1 TAN 192-3 2-40847 241681- 2,43%'99 Depicted land should not be used for 2-7o?9? .275' ;2@38;8 2m?88?S 21S81c.5 navigation. 3114 239AqZ -239112f-1- Position lines are for the edges of .2q5jg,5L2 C3 *.? 7- warmer water. The thin streamline is 33il-(62 2129 2428OZ ZT2 so a an estimated location for the max- 3;L1'+02_o 3"+'O@ imum current. Measured current speeds may be shown. Position based on data 0 to 2 days old. ..-Cos, Position based o' n data3to 7 days old. 8.6 Position based on data 8..-.. days or more old. 30- Mean position for month. V K very cold K cold M mixed W warm 29 . ..... kox L\ bt@ 2'@ 01 5r3o, C3 A 2,@ A NEXT UPDATE.:''' MIA. /00 f Z: 26 .... ...... 25 78. -83 4.. 9 2 PEM FLOW CHART 2450 NOAA Miami SFSS GULF STREAM Date:,Z @i J-A A/ ff -1993- .77 Aks 2.19862 2%A87z z7r ea@q 219!2c ZN-4- - Depicted land should not be used for 76Y)3 ZqOaS 258 elm navigation. Q;IY 14-6a52 Position lines are for the edges of 6A-49 warmer water. The thin streamline is ZV 84h. 232&35: 2144 42 7 an estimated location for the max- f imum current. Measured current 2XIRelb _)Aoky speeds may be shown. Position based on data 0 to 2 days old. 3' 'AS M08,, '87 Position based on' data3to 7 days old. 6 Position based on dat a 8.*.. days or more old. 30. 31' Mean position for - month. V K very cold 3 0* K cold M mixed W warm '29 @01 bb Is*% 28 .... ... io 2,@ NEXT UPDATE X; .00 :7' 000 A.- /00 26 _7!7'7 -7 T ........ ------ 25 T 79 T @2 EM FLOW CHART " 2450 NOAA Miami SFSS GULF STREAM Date: 2 (6 &T A.pj 19 133 2YOS(ol 231870 ZY3880 Depicted land should not be used for 2707?8 25 2 2_13 2 8 is- 2618 Sq 5- navigation. 3140 Z-58252 2538S@, :ZYc-&,9 Position lines are for the edges of *344`4 warmer water. The thin streamline is 2-Yo8 go 2 Y Y83Z ZY 2- 8 an estimated location for the max- 2_Y28&1V -2.52 Z (0 o imum current. Measured current speeds may be shown. Position based on data 0 to 2 days old. 3' Position based 'on' data3to 7 days old. 8.6 Position based on data 8'..@.. daysormoreold. 30- 40, Mean Position for month. 3 V Kvery cold 0 K cold M mixed W wa rm 29 0.. ,kol 2@' -To, Z.: 2 0 NEXT U PD A T E EA@ I . 4 100 26 78. .79 rEM JLOW CHART ff 2450 NOAA Miami SFSS GULF STREAM Date: J-A Al 19 8.q ),Lq8s7 2398.,@ 2#286f7 176;t2A 11 . f Depicted land should not be used forIr ff @B@ Y3 7 19 -)all- IWAS t)2 navigation, n D r 13 OuAJIY Position lines are for the edges of q 7/71-/ 3ab-7 warmer water. The thin streamline i's U182S an estimated location for the max- I6#&:rL3 imurn current. Measured current .2 7o &Z 2-60,9Sz speeds may be shown. .2 A 9 P "inY Position based on data 0 to 2 days old. Position based on' data3to 7 days old. 8.6 Position based on data.8@-... days or more old. 30 20 Mean position for .0 -7. month. 3 ... .... V K very cold K cold M mixed W worm 29 0. k0110 .0 bb '5 & 2@ T. I; CO@ NEXT UPDATE M tA.-- 100 26 25 79 82 _f* I I f-EM FLOW CHART 2450 NOAA Miami SFSS GULF STREAM D ate: 3 & T. A N 19ELs- 270797- 2AO Depicted land should not be used for I @ navigation. S 2"S 6 Z@L-512-143 14LEA0 9 4t-j;Z!R WA k tj_,CP_&@ Position lines are for the edges of warmer water. The thin streamline is un R 24 YA A 9 lk 2 A 2 A an estimated location for the max- imum current. Measured current 3Asou .4r:198,59 speeds may be shown. Position based on dataO to 2 days old. 17 Position based on' data3to 7 days old. .86 Position based on data 8- days or more old. 31 Mean position for 8's. month. 36 VK very cold K cold M mixed W wo rm 29 @ot J: bb &S 28 01 7, .-2 NEXT UPDATE 2@' 00 26 . ...... ...... 7t.:: 25 4 83'.'* 79 82 'ITZ, .9 JEM, FLOW C HART 4F 2450 NOAA Miami SFSS GULF STREAN Date: _C2 Z F-EB _1983 113 2309(ato 23@FSGY 2N6 Depicted land should not be used for 2q0?qS 2,;q 2 L/:3 8 2 2 Ljo 8 I.S, navigation. - 322 2LI2 3 2_1 @857 25'218op 7-5(P'7?9 2(o079R// Position lines are for the edges of 346074 3"-@ 2ED BY ZLJ 0 IR2 2LJT 89 warmer water. The thin streamline is I an estimated location for the max- 37-4'pf 2-o 3Tq 2511o3 259 SC?9 2 (0 (0 19 imum current. Measured current 3!954,9.3 21 speeds may be shown. 38q6 - 21,8955 2-&S S Y1 2/6 2 13,Y8 Position based on data 0 to 3 6(a &G3 38S 2s8 S q,? 2S-z 13 SY 2 days old. 1,91 (OLILI Position based' on' data3to 7 days old. .86 Position based on data 8'. days or more old. .0: Mean Position for month. 36 V K very cold K cold M mixed W wo rm '29 \\o, @01 bbc) 2 01 ..... .. NEXT UPDAT E 00 26 ...... XI 2S _J .8 79 rEM FLOW CHART 450 NOAA Miami SFSS GULF STREAM Date: 0,4 FEA _198,X 176 Depicted land should not be used for n5 ADZ navigation. _3214 79 J7 -32-2 ,F-DDY Bo(iro.DEZ 2,,@r)AZ:D Position lines are for the edges of _-@4 7,54 warmer water. The thin streamline is 2"eas 2,@<A9 7- ZAIIA92-- an estimated location for the max- 12@29 37, 72 1 imum current. Measured current 2134AS6 a_,T-7A@4P _3ALA P.5 speeds may be shown. 3 8A&52- 38?:@@ 24to tq Position based on data 0 to 2 days old. data3to Position based on' 7 days old. 32.. .86'. Position based on data.8'.,-- days or more old. 30: * 8,5, Mean position for month. 36 V K very cold K cold M mixed W worm 29 \01 7%j %%o . .. ... bb5' 'N\"i 28 0 7:7 NEXT UPDATE too MiA.- C VO ....... k 26 .......... 2S 78. .83 9 'ITEM, FLOW CHART -4 2450 NOAA Miami SFSS GULF STREAf 1 2_qJe7o24_S8S9 24SR Date: OL7-F@. 19a3- 4 Depicted land should not be used for 12 239 2q/ 826 navigation. 5- 2!t_5;9QS 2517 9 92557c?8 Position lines are for the edges of 341751 34 RY: 2L41 BP@3 warmer water. The thin streamline isS an estimated location for the max- 31872 S-f 5 2-5-9899 2 (a VS" imum current. Measured current 3B5 G SS 119 speeds may be shown. :2 (pj 857- 2- G 3 RS,3 215*88@8 Position based on data 0 to 3 8 (P (0 SS, s5k - 2-52851 2 If 6 &@ q 2 days old. - 0 (V L/ go -.C1.AS 2_q57 8 (Q(40 n a Position based o' dat '3to 7 days old. :2 86 Position based on data.8. days or more old. 30 31, Mean position for month. 36- (D VK very cold- K cold M mixed W worm 29 .(9 7 K, 1 7 kol . . . . . . ft%o 7. 2 bb5' &'54 01 2,7 NEXT UPDATE '2@ 7 1, /00 f, .2 7 - . . . . . . . . . . . . . . . 7: ...... 25 7-*. _'7 V. '79 4. 82 # 2450 rEM,,FLOW CHART NOAA Miami SFSS GULF STREAM Date: Q!? FF.9 19S3 2_7@o 8 24 4(087- Depicted land should not be used for (a 0 89 navigation. o%9S 2 4 266M .319 It 8 F 3 1 cl",@ 26(aRT6 2648691 74@oRS5 Position lines are for the edges of 3 31- 7 (a warmer water. The thin streamline is 2-SoRS3 2'Y98/aO 2147RU an estimated location for the max- 7 2LIY8y 2 current. Measured current 396683 38S o q/825 23RSLB 'Mum speeds may be shown. 2!96 2S.3Boo.2_(,o8!2 3148(061 3%1- Position based on dataO to 2 days old. 3 sto (0 Y.(O S. Position based o h data3to 7 7 days old. Position based on dat days or more old. jo, 31' Mean position for 0 month. 36. VK very cold cold M mixed W worm o9 %%o 65, -s'\O 2@ 46' b 01 .... .. 0@ ..A .'2 NEXT UPDATE MIA.- . ....... 100 2, 25 ...... ... .. 83: _8 i 79 42 FEWFLOW CHART If 2450 NOAA Miami SFSS GULF. STREAM Date: 19 8,1@- .2 Z@n7T@- 12,98,44 Depicted land should not be used for -;.) navigation. -313 M - ZVILU- 2L2B-6-,C-> - 3 7-2@- Position lines are for the edges of 32L@ warmer water. The thin streamline is R41 an estimated location for the max- 2,u A A62- imum current. Measured current 7A 78Z2- 2-'5-0@0@ speeds may be shown. - -------- Position based on data 0 to 2 days old. .,3,3 COS Position based on data3to :'87 7 days old. 3 2. q 86 Position based on data.8---V days or more old. 30 31 Mean position for month. ..... .. '7' V K very cold K cold M mixed W worm 29 OINO bb. N'5 01 <5 A O\\ 7.7: C 27 NEXT UPDATE 7 28@ MtA 7 100 26 dpo 2S 78. 7 83' 79 f EM fLOW CHART 2450 NOAA Miami SFSS GULF STREAM Date: 2_76 221 A A A 74t Depicted land should not be used for navigation. ?A22()e).2AA899 2 7^ A 9Z -3 Z.z 7 7U Position lines are for the edges of 4La warmer water. The thin streamline is 9-41-R A@4 _23 %5@@ an estimated location for the max- I imum current. Measured current speeds may be shown. Position based on data 0 to 2 days old. Position based on' data@to 7 7 days old. 8.6 Position based on data:8,@- days or more old. 30 Mean position for month. 30 VK very cold Kcold M mixed W worm 29 %0, Pp 4 %0 7 2 7 05 io 7- 7. . . . . 22@ NEXT UPDATE.::,-' MIA. 7- /00 26 25 7. ... 9 .8-3- 4. 82 f--EM FLOW CHART # 2450 NOAA Miami SFSS GULF STREAM Date: F& 8 19-W Depicted land shou Id not be used for 2-7,0498 2%7 navigation. 32078 3zc) 2649C)o 270900 212993 2 25gssq 2(05g6s _ 251844 Position lines are for the edges of 3q02& 3qs@ 2YqaSo 2S18S9 2SIS(ol warmer water. The thin streamline is SS7738 34042V an estimated location for the max- 7 2308q 2 3q @335 'm'm current. Measured current speeds may be shown. 23SBIS 2q080"+ 24 5 (30 3tqO.3 3854 Position based on data 0 to 2YSSoo 25q72-9 2 days old. .:33 n data3to 2(6 0 Position based o' 7 days old. 3'2' .86 Position based on data 8:. days or more old. 30. 31' Mean position for 8,5,* month. V K very cold K cold M mixed W warm 29 8 6% bb 2 04 (35) 50' @01 @s '3 @c .27 NEXT UPDATE 2@ miA. 0 /00 26 2s 81. 79 -.83: 82 ;TEM FLOW CHART 2450 NOAA Miami SFSS GULF STREAA Date: I R FE.5 - 19 83 )-ZQn__7 Depicted land should not be used for *A- 2saam .2sagn navigation. .32F?7 7LL .3-40 -7-1h9ah .2 Position lines are for the edges of 35RU& 3_74t; warmer water. The thin streamline is Ae)A ly q VA31BW 2-336417- an estimated location for the max- .3 3A imum current. Measured current 26LBAIM .2k!26ky -Z-3 C&M speeds may be shown. 2-3 .1 -82 Sy!2_ Position based on data 0 to 2 days old. z6t) z2L ..C%4 Position based on* data3to, 7 days old. 32..: 86 Position based on data days or more old. 31 pow. Mean position for month. 36- VK very cold K cold M mixed W warm 29 ....... 0. 'ho 6 1% 28 0 co@ 2Z ...... NEXT UPDATE .2 .6 100 2t so 25 ...... ...... 79 82 JEM FLOW CHART 2450 NOAA Miami SFSS GULF STREAN Date: 1983 I'L JIUSP 2 3W72, 2._,qjA ZL 2-7.6 7V 9-7, 3C30j 9 Depicted land should not be used for 2-"2/o_ Z7A-gn navigation. -42A 7/1 r - if 276673 7SIAMM 241-28 Position lines are for the edges of 6 1 f warmer water. The thin streamline is an estimated location for the max- imum current. Measured current 38 -18 speeds may be shown. Position based on data 0 to 2 days old. Mos' Position based o' n data3to 7 days old. Position based on data 8'...,. 01 days or more old. 3 8 Mean position for month. 7 30' VK very cold K cold M mixed W worm 2o kol ON V bY b 28 *01 27 NEXT UPDATE .1 TI., 1-1-0 MiA.- .100 2( 25 78. 83 79 TEM FLOW CHART * 2450 NOAA Miami SFSS GULF STREAM Date: 2. 3 F 19133 I's 2-3SR?-/ .2458-ka 2S168R Depicted land should not be used for 29o8 navigation. 32o?Ro -32-5 a 2-739o.5 2*7789S -0 2- S 285_5@ 2S3F>qs 2_qMl Position lines are for the edges of 31-4 167-S *?- 3S7 9,7,oSSn 2*3oSY(o 23(n92S' warmer water. The thin streamline is 3?q ?-Z6 3?8 an estimated location for the max- 2(0079<7// imum current. Measured current *,,'I Ispeeds may be shown. Position based on data 0 to 382 3M 2 days old. Position based' on' data3to '87 7days.old. 2. .86 Position based on data 0 days or more old. .30 Mean position for 8,5- month. 0001*- V K very cold @6 T K cold M mixed 7 W warm '29 C kol .0% bb 2@ jo C3 7. T 7 NEXT UPDATE 7 7 '2' 6 MIA.' 00 fro 26 X_ 25 7 _7' of.. '19 83'. 2 TEM FLOW CHART 7r 2450 NOAA Miami SFSS GULF STREAM Date:-25-f-El- 19 83 .2.(oog9o ZiMo Depicted land should not be used foi 2,2o 27&100 23:ySJ3 :Z7Lj88S- navigation. 31878q -3)9-+ t 2608s zSSS5 25yssb Position lines are for the edges of 3Lto7SS _3qq 13 ZIZEW Z30'RqS' 23(082.5 warmer water. The thin streamline is an estimated location for the max- 3'51o':@o 5 395( 25o-@%p 2too294,// irnum current. Measured current speeds may be shown. Position based on data 0 to 2 days old. COS Position based o' n data3to 7 days old. 3 6 Position based on data 8'@... days or more old. 30: 3 81i Mean Position for N. month. 3 @of V K very cold 0* K cold M mixed W wa rM VVII @01 6@,5@ bb 1% 28 S NEXT UPDATE 7. 100 f 26 Now 1!1!0. .. ...... 25 79 4F rEM FLOW CHART 450 NOAA Miami SFSS GULF STREAM Date:21-8@@. 19 &5 2 5,4xR Depicted land should not be used for navigation. 9nA 2 2.70/1- 47Z202 22 9__,q1)1q39 ?.:Rglq Position lines are for the edges of 3-LA-7: 10 7_Q warmer water. The thin streamline is r I - - - - - - -7- an estimated location for the max- imum current. Measured current speeds may be shown. F@ 2 6'94 3 8,5_ Position based on data 0 to 2 days old. 8 Position based on' data3to 7 days old. .8.6 Position based on data 8*.. m daysor oreold. 30 8 Mean position for 's month. V K very cold ..0 K cold M mixed W wa rm 2.9 @01 .%00 0 bbS '1 2 ...... 8 @01 21.1 NEXT UPDATE MIA 100 26 _7 25 78. '::7 :J. - 79 82. TEM FLOW CHART Ir2450 NOAA Miami SFSS GULF STREAM 'Date: DZ MAR ign IISSAR 4nA 7A Z<Y_,q Depicted land should not be used for navigation. 2 YAI.-,C 2_4 -4 'A:L2- - 3 A Position lines are for the edges of L26 . 3_45_@_ warmer water. The thin streamline is 2,08D_@L 24!@Ape) an estimated location for the max- J? P,5AA n imurn current. Measured current _377422Y speeds may be shown. Position based on data 0 to 2 days old. Position based on' data3to :,87 7 days old. .3 8.6 Position based on data 8:,-*@'."#I days or more old. 0, Mean position for month. V K very cold 3() K cold M mixed W warm '29 kol %%% 1511 28 oi NEXT UPDATE. 7.. 2` 7. /00 2e, 2.5 .78. @7_ 7 79 I* I I (EM FLOW CHART 2450 NOAA Miami SFSS GULF STREAM Date: 0 19 -Ea 23587,7 2-SORS4 2-G:z8 Depicted land should not be used for 27@0719 2(oSS62 2598SR 2 navigation. 3 7-44 r@ 0 33 23782S 2q0'8I(6 :24SIRoR Position lines are for the edges of 356 7 25 35-@ warmer water, The thin streamline is an estimated location for the max- 30:W4 15 - 3'7@ 2- F imum current. Measured current speeds may be shown. Position based on dataO to 2 days old. Position based o' n data3to 7 days old. .,86 Position based on data 8'@ days or more old. 30: Mean position for 8,5, NV month. V K very cold K cold M mixed W worm 2 9 x % %o b 28' ... ..... 01 ...... .... :27 NEXT UPDATE."': V-1 .. .... *; I-MAR 83-- M4A.- ....... IN /00 26 .... ....... . ...... 25 78. J 83'.. 79 82., 1, rEM FLOW CHART 2450 NOAA Miami SFSS GULF STREAM Date: 04-MAK- 19&1 .2 .3 9.@;C7> 81. 3DI "87 ivula ppicted land should not be used for lhavig "fin. u2A37 L36831 Z'i P 61L Position lines are for the edges of 16 129 -3 7/4.7 warmer water. The thin streamline is I I .@ 2-6-11917 2-60 7% an estimated location for the max- 2L YQQ_ imum current. Measured current a, speeds may be shown. Position based on data 0 to 2 days old. Mo n data 3to Position based o' 7 days old. Position based on data 8 days or more old. jo, Mean position for month. 01 VIK very cold K cold M mixed W wo rm 29 %0( bb5' .28' 01 21. NEXT UP DATE 28' Ai iA. 100 2, 25 J. 79 Nd EM FLOW CHART 24SO I NOAA Miami SFSS GULF 5TREAM 2,22A7e) .239 24787A Date: 09,MAK- iqB& 774 Depicted land should not be used for ZZQ2&- ZE?@a 2_A@ LlEaas!2 navigation. 134;u- MD-7j Position lines are for the edges of 16-IZ- warmer water The thin streamlinp is ------- an estimated location for the max- imum current. Measured current speeds may be shown. 380-6-, Position based on data 0 to 2 days old. Position based on' data3to 7 days old. 2. 6 Position based on data daysormoreold. 30. 31 7 19 Mean Position for month. 7 V K very cold K cold M mixed W warm '29 7 7 %01 .0 r3 2,9 io, 7. 7 '2 NEXT UPDATE.::.' 7.7". .6 % . A 26 25 8.3., 79 ,,TEM FLOW CHART it 2450 NOAA Miami SFSS GULF STREAM Date: JIMA R 19--83- 2-_7_n7qq Z822 Depicted land should not be used for9F_ navigation. )^-19 C) ZLq-Aj q-- 2S36a5 X5383P Position lines are for the edges of I19AIR 24tt!>616 2-4 44 ;Zr) warmer water. The thin streamline is 37@7kq/@, 389 an estimated location for the max- imum current. Measured current speeds may be shown. Position based on data 0 to 2 days old. ::3,7 C" Position based on data3to 7 days old. .86 Position based on data,81 .,.. days or more old. jo Mean position for 81 month. 36 V K very cold K cold M mixed W worm 29 7 10 0@\o ...... 00 bb N'S'\ 28 @o C3 2 NEXT UPDATE 7 '2' 6 001, 26 7 25 81.. 9 83 7 I f rEM FLOW CHART 2450 NOAA Miami SFSS GULF STREAM Date: 1983 22696 23-M-2 2.To Depicted land should not be used for 2-7-o 28s, 2&,5,&aq 7-S(aRS4 navigation. 32LJ775 '3 3 3 -7 2 382-3 2-qo R 11 Position lines are for the edges of 3(oo?,30, 37 9:, 94? /Z @ warmer water. The thin streamline is 31-3692- 3 Ski 2-57-498 Z607 an estimated location for the max- imum current. Measured current 3906110 319 5 (c, speeds may be shown. Position based on data 0 to 2 days old. mois Position based on' data 3' to 7 days old. Position based on clat@a:8,---- days or more old. 30- Mean position for 19 month. 01 VK very cold 3' K cold M mixed W warm 9 kol T bb N'S 28 2, NEXT UPDATE .6 100 26 2s 78. 4'. 83: 79 82 _ff GULF S rEM FLOW CHART 2450 NOAA Miami SFSS TREAM Date:-/(P,-MAR 19S3 235869. 24 2S2 87-9 Depicted land should not be used for 24o79 9 710 9 7 Co 2to C-, A & 4 2SSA,51,* navigation. 3 1 3 2 2 13 20834 ZB 241832- Position lines are for the edges of 3 3'94@o3 2_4 4 81 2-5/Soo 240919 warmer water. The thin streamline is an estimated location for the max- imum current. Measured current speeds may be shown. Position based on data 0 to 2 days old. Position based on' data3to 7 days old. .816 Position based on data 81* daysormoreold. 30. 31' Mean position for j month. 36- V K very cold K cold M mixed W Wo rm 29 00 6:\\\ bb 1%5 2' 0 V 27 NEXT UPDATE.".' 7 7 I 'A 100 26 25 ...... ...... 79 162 .,Em FLOW CHART 4F 2450 NOAA Miami SFSS GULF STREAM Date: T8_MAR___ 198 3 2qo!R?-q .2qMb 2 5 Depicted land should not be used for a-7-0:Z99 .I navigation. 32 712 2-q R RLI?L 2 2 45 Position lines are for the edges of M7 i ,q@ warmer water. The thin streamline is 2qogiS 2LI 3 R 0299RO an estimated location for the max- imum current, Measured current speeds may be shown. Position based on data 0 to 2 days old. At .0 Position based o' n data 31o 7days old. .8.6 Position based on data 8'-.'* days or more old. 30. Mean position for 8's month. V K very cold 0 K cold M mixed W worm 29 0@10 01 .0 % b5' 46 %Ab .2 01 S 7 1:, NEXT UPDATE T., MIA-- '00 2 79 2 JEM FLOW CHART 2450 NOAA Miami SFSS GULF STREAh Date:24-NAR- 19 &3@ Depicted land should not be used for navigation. A) 79P 476 Position lines are for Sp Z. the edges of warmer water. The thin streamline is 2.&4)A31 13F3F@2,5- 2-39N6 an estimated location for the max- 9 V-) I imum current. Measured current AIn speeds may be shown. Position based on data 0 to L7 6-., 2 days old. 3 10 49-1 C. Position based on' data3to. P1, 7 days old. .86 Position based on dat a days or more old. 30. Mean position for month. 01. V K very cold K cold M mixed W worm '29 NO 28 bb jo 2 NEXT UPDATE.:- 2.6 MIA 100 2( ... .... 2s 7 8,3 79 82 TEM FLOW CHART 2450 NOAA Miami SFSS GULF STREAM 23&5j3,2qo 67E 2qY8 Date: 23 MAP, 19Ba z7a"M@ 27-31 -3 Depicted land should not be used for - 210883 268890 2*7/985 navigation. 30?800 315 3 Z@2R56 2588-c6 2908S@2 Position lines are for the edges of 32 IR warmer water. The thin streamline is P an estimated location for the max- 350-9-YIR 35q? 1 236,9/9 V/SlRoR 2,Y_RBp imum current. Measured current 3--;. 0 V;@ I f. 2( ,2 speeds may be shown. -0 Position based on data 0 to 38o?oc) 3--@,o 2 days old. @?j Position based o' n data3to 7 days old. .72. .8.6 Position based on data 8 days or more old. jo, Mean Position for 81S month. V Kvery cold K cold M mixed W warm 29 %0, % bb 28' @01 @AS NEXT UPDATE J,A 100 2, 2S -8 79 82 4f@ EM FLOW CHART 2450 NOAA Miami SFSS GULF STREAM Date:25MAR 19&1 IJvA A 6 Depicted land should not be used for J:@@AAA navigation, :@2_3 @3/7 1@086 1-7 3_6 2S -- , . - - 7& - - 6 .2 msASj_._ 26&&@ c_ Position lines are for the edges of .3497j9 warmer water. The thin streamline is an estimated location for the max- imum current. Measured current speeds may be shown. Position based on data 0 to 2 days old. ..Cos n 3to Position based o' data 87... 7 days old. .32.. 86 Position based on data 8' days or more old. 30. 31* Mean position for month. .... .. 36- V K very cold K cold M mixed W warm '29 tp 04 0, .0(%o bb 28 '@c 7 NEXT UPD ATE -2 6 M oA /00 26 25 -83 79 @ 2 Ilc ! @ . @TEM., FLOW CHART 2450 NOAA Miami SFSS GULF STREAA Date: 1983 7 21MR67 2=)-AA72- 2-3-18" ZIQ4a IQ@S_ Depicted land should not be used for navigation. 332-7a 2, 6 P.4 7 2:4@3 F)SL Position lines are for the edges of 3&-7-2-2- 21) Z38 A i warmer water. The thin streamline is an estimated location for the max- imum current. Measured current speeds may be shown. Position based on data 0 to 2 days old. - Position based on' data3to 7 days old. 32" .86 Position based on data 8 days or more old. 01 Mean position for month. @7 V K very cold 7 K cold M mixed W worm 29 7: A 010 "'10 bb5- 4,3.\ID28I .7 liol @15 .27 NEXT UPDATE - 1001", 7 7: .3 7 25 7 4%. Z9 2 JEM FLOW CHART 2450 NOAA Miami SFSS GULF STREAM 22-766!1 .23687o 2-42-84L Date: -3 0 HA It-19ft 2 1c) 7e-?q Depicted land should not be used for L ZAnSA9 2A 2,42a navigation. 328 25 7A_'.@q(5 21_41A,52 -ZZJSL@__C Position lines are for the edges of 3AZ;@ Z2_Z .3177,7 warmer water. The thin streamline is I I -r-r7- 2,UIAZP_ an estimated location for the max- 3_7(p6p,)n 3= ).A62:79911 imum current. Measured current speeds may be shown. Position based on dataO to 2 days old. n Position based o' data3to 7 days old. 172. 8.6 Position based on data 8'..@.. days or more old. 30 Mean position for 81 month. 7' VK very cold ....... K cold M mixed W worm 2.9. % .000 24 b b 0a 5) jol ou ...... AS ... ... .27 NEXT UPDATE MIA- 001" 2, ..... ..... 23 ........ . .. ..... ...... 8 1.. 79 Page 25 6) Discussion of FOTEC Data From the historical data we expect that there will be variance in the current and temperature on three time scales. Annual cycle time scale variability would require several to ten years of data to resolve. Our much shorter time series of profiles will not resolve these questions although the STACS data from the Palm Beach area will give us a good idea of the variability to expect. Also we can extract a part of the signal from satellite IR which can give us estimates of the position of the Gulf Stream edge and surface temperature which could be used with a current model. At present however our best estimates come from the historical data which suggests a transport variation of about +3 X 106m 3s-1which account for about 45% of the current variance. Long term current observations are the only method of accurately estimating these effects at the proposed FOTEC sites. Since the deep water temperatures are quite stable over the long term surface temperatures derived from satellite data are quite satisfactory to estimate the thermal resource. For this purpose the data would need to be worked up on an image by image basis taking into rejecting cloud contaminated data. The second band of variability is the 2-10 day period fluctuations. These periods are known to be associated with the meanders of the Gulf Stream and include the dynamics of shelf waves and spin off eddies. Had this work been funded on the originally proposed schedule we would have been able to observe two to ten cycles in these period bands by alternating between stations barring an interpretation by hurricane. However late funding forced a winter experiment which was repeatedly interrupted by cold fronts. From the satellite data on 19, 21, and 24 Page 26 January 1983 we can see that the Gulf Stream edge is south of both stations explaining the relatively moderate currents. On the 19thof January there is an indication of a warm water intrusion from the east at the easternmost station given by cross-section I which is confirmed from the in-situ temperature data. These data most likely are explained by the presence of a spin off eddy. Page 27 7) Conclusions and Recommendations From the data above we have a good idea of the variability to be expected at the two possible FOTEC sites near Key West. By comparison of our mean profiles of temperature and velocity with those in Figure 3 we can clearly see that the currents we observed were far from the maximum or minimum currents to be expected at this site although our mean values are close to the longer term mean. The remotely sensed temperature data also shows that during our observation period that the Gulf Stream axis lies consistently south of our anchor stations. The temperature section data also shows the edge of the stream farther south than our anchor stations. However, the remotely sensed 'temperature suggests that during other periods that the stream lies farther north at times brushing against the Florida keys. Both remote and in-situ temperature data shows the clear presence of spin-off eddies near the FOTEC sites as we would expect from the historical data in Figure 5 and 6. All of our historical data and the data recorded in this program fall short of the level of coverage required for a thorough engineering study required for the cost effective design of such a costly project as an OTEC plant. What is needed for the surface temperature and temperature gradient information can be extracted from a satellite remote sensing program which concentrates on measuring temperature at the proposed sites and rejects those images which contain significant cloud cover. The current data needed for the design process will be more difficult to obtain. The current meter group at RSMAS can maintain current meter moorings in this reg ion for 6 month deployments. Our 'past Page 28 experience tells us that at least one year of data is needed to define the seasonal cycle. However a mooring extending all the way to the surface is not practical for these lengths of time. We must settle for current data up to 150 meters from the surface which will often omit the strongest currents. One possible solution to the near surface current problem would be the use of a CODAR (Coastal Ocean Dynamics Radar) which relies upon remote land based radar transmitters and on site computer analysis to interpret the scattered returns in terms of surface currents. Such a system is now in use in the STACS experiment off Palm Beach on an experimental basis. Since the worst case currents are likely under storm conditions a remote sensing current system may be the only practical solution. Another approach which might work is to use an acoustic Doppler current profiler to measure the currents remotely from bottom mounted acoustic transducers. These systems like the current meters are restricted from measuring the upper 10% of the water column but do give much better spatial resolution than a typical current meter mooring. These acoustic systems are still in the experimental phase of their development but do offer potential savings compared to moorings. Because a potentially vulnerable mooring does not exist, these systems may be more reliable in the long run permitting longer term or even permanent installations with cables to shore for power and signal transmission. Page 29 REFERENCES Brooks, D.A., 1975. Wind-forced continental shelf waves in the Florida Current. University of Miami/RSMAS Technical Report 75026: 268 pp. Brooks, I.H., 1979. Fluctuations in the transport of the Florida Current at periods between tidal and two weeks. J. Phys. Oceanogr., 9: 1048-1053. , and P.P. Niiler, 1975. The Florida Current at Key West: summer 1972. J. Mar. Res., 33(l): 83-92. . and .1 1977. Energetics of the Florida Current. J. Mar. Res., 35: 162-191. Chew, F., 1974. The turning process in meandering currents: a case study. J. Phys. Oceanogr., 4: 27-57. Cochrane, J.D., 1972. Separation of an anticyclone and the subsequent developments in the Loop Current (1969). In Capurro, L. and J. Reid, eds. Contributions to the Physical Oceanography of the Gulf of Mexico. Texas A & M Univ. Studies, Gulf Publ. Co.: .91-106. Vaing, W., and D. Johnson, 1972. High resolution current profiling in the Straits of Florida. Deep-Sea Res., 19: 259-274. , W., 1975. Synoptic studies of transients in the Florida Current. J. Mar. Res., 33: 53-73. p C.N.K. Mooers, and T. Lee, 1977. Low-frequency variability in the Florida Current and relations to atmospheric forcing from 1972 to 1974. J. Mar. Res., 35: 129-161. Evans, R.H., and K. Leaman, 1978. A comparison between the Ming profiling current meter and the White Horse acoustic profiler. J. Geophys. Res., 83: 5515-5521. Fernandez-Partagas, J., and C.N.K. Mooers, 1975. A subsynoptic study of winter cold fronts in Florida. Mon. Wea. Rev., 103: 742-744. Gentry, R.C., 1974. Hurricanes in South Forida. In Gleason, P.J., ed. Environments of South Florida: Past, Present, Future. Memoir to Miami. Geol. Soc.: 73-81. Hurlburt,' H.E., and J.P. Thompson, 1982. The dynamics of the Loop Current and shed eddies in a numerical model of the Gulf of Mexico. In J.C.J. Nihoul, ed., Hydrodynamics of Semi-enclosed Seas. Elsevier Scientific Publishing Co., Amsterdam: 243-298. Kielman, J., and W. DUing, 1974. Tidal and subinertial fluctuations in the Florida Current. J. Phys. Oceanogr., 4: 227-236. Page 30 References 2 Lee, T.N., 1975. Florida Current spin-off eddies. Deep-Sea Res., 22: 753-765. , and D.A. Mayer, 1977. Low-frequency current variability and -spin-off eddies on the shelf off Southeast Florida. J. Mar. Res., 35t 193-220. and L.P. Atkinson, 1983. Low-frequency current variability from Gulf Stream frontal eddies and atmospheric forcing along the south-east U.S. outer continental shelf. J. Geophys. Res. (in press) . $ I. Brooks, and W. DUing, 1977. The Florida Current - its structure and variability. University of Miami Technical Report, RSMAS 77003: 275 pp. L.P. Atkinson, and R. Legeckis, 1981. Observations of a Gulf Stream frontal eddy on the Georgia continental shelf, April 1977. Deep-Sea Res., 28A: 347-348. Legeckis, R., 1975. Applications of synchronous meteorological satellite data to the study of time dependent sea surface temperature changes along the boundary of the Gu.1f Stream. Geophys. Res. Lett., 2: 435-438. Leipper, D.F., 1967. Observed oc eanic conditions and Hurricane Hilda, 1964. J. Atmos. Sci., 24(2): 182-196. 1970. A sequence of current patterns in the Gulf of Mexico. J. Geophys. Res., 75(3): 637-657. J.D. Cochrane and J.F. Hewitt, 1972. A detached eddy and subsequent changes (1965). In Capurro, L., and J. Reid, eds. Contributions to the Physical Oceanography of the Gulf of Mexico. Texas A & M Studies, Gulf Publ. Co.: 107-118. Maul, G.A., 1977. The annual cycle of the Gulf Loop Current. Part I: Observations during a one year time series. J. Mar. Res., 35(l): 29-47. Molinari, R.L., and R.E. Yager, 1977. Upper layer hydrographic conditions at the Yucatan Strait during May, 1972. Mooers, C.N.K., and D.A. Brooks, 1977. Fluctuations in the Florida Current, Summer 1970. Deep-Sea Res., 24: 399-425. Morrison, J.M., and W.D. Nowlin, Jr., 1977. Repeated nutrient, oxygen, and density sections through the Loop Current. J. Mar. Res., 35(l): 105-128. Niiler, 1976. Observations of low-frequency currents on the Western Florida Continental Shelf. Memories Societe Royale des Sciences de Liege, Series 6, 10: 331-358. Page 31 References 3 Niiler, and L.A. Mysak, 1971. Barotropica waves along an eastern continental shelf. Geophys. Fluid Dynamics, 2: 273-378. , and W.S. Richardson, 1973. Seasonal variability of the Florida Current. J. Mar. Res., 31: 144-167. Nowlin, W.D., 1971. Water masses and general circulation of the Gulf of Mexico. Oceanology International, 6(2): 28-33. and H. McLellan, 1969. A characterization of the Gulf of Mexico waters in winter. J. Mar. Res., 25(l): 29-59. -, and J.M. Hubertz, 1972. Contrasting summer circulation patterns for the eastern Gulf-Loop Current versus anticyclone ring. In Capurro, L. and J. Reid, eds. Contributions to the Physical Oceanography of the Gulf of Mexico. Texas A & M Univ. Studies, Gulf Publ. Co.: 119-138. and R. Reid, 1968. A detached eddy in the Gulf of Mexico. J. Mar. Res., 26(2): 185-186. Parr, A.E., 1937. Report of hydrographic observations at a series of anchor stations across the Straits of Florida. Bulletin of the Bingham Oceanographic Lab., Yale University, 6: 1-63. Pillsbury, 1891. The Gulf Stream. Report of the U.S. Coast and Geodetic Survey for 1890. Appendix No. 10: 461-620. Richardson, W.S., W.J. Schmitz, Jr., and P.P. Niiler, 1969. The velocity structure of the Florida Current from the Straits of Florida to Cape Fear. Deep-Sea Res., 16(suppl.): 225-231. Schmitz, W.J., Jr., and W.S. Richardson, 1968. On the transport of the Fljorida Current. Deep-Sea Res., 15: 679-693. Schott, F., and W. DUing, 1976. Continental shelf waves in the Florida Straits. J. Phys. Oceanogr., 6: 451-460. Smith, J.A., B.D. Zetler, and S. Boida, 1969. Tidal modulation of the Florida Current surface flow. Mar. Tech. Soc. J., 3(3): 41-46. Stommel, H., 1965. The Gulf Stream. Univ. of California Press: 748 PP. Stubbs, W.O., 1971. The baroclinic. stucture of the Florida Current. M.S. Thesis, Univ. of Miami: 57 pp. Stumpf, H.G., and P.K. Rao, 1975. Evolution of Gulf Stream eddies as seen in satellite infrared imageiy. J. Phys. Oceanogr., 5: 388-393. Thompson, R. , 1971. Topographic Rossby waves at a site north of the Gulf Stream. Deep-Sea Res., 18: 1-19. Page 32 References 4 Williams, J. , 1973. Oceanographic Instrumentation. Naval Institute Press: 189 pp. Wist, G., 1924. Florida and Antillenstrom, eine hydrodynamische untersuchung, Veroff. Inst. Meeresk., Univ. Berlin, NFA 12: 48 pp. Zetler, B.D., and D.V. Hansen, 1970. Tides in the Gulf of Mexico - A review and proposed program. Bulletin Marine Sci., 20(l): 57-69. Z9LL LOM 8999 6 . I I N It 4 A A A I A i 4 A -i A