The study of shelf tides will be continued during autumn 

 1973 in the Middle Atlantic Bight area. It will be necessary to 

 develop shallow water tide gages for this study. 



Organization: AOML/NOAA 



Investigators: R. Molinari, F. Chew, D. V. Hansen 



Project Title: Circulation Studies for CICAR: Lagrangian 

 Measurements of Ocean Currents 



Grant No.: AG-253 



The data collection phase of the Lagrangian Current 

 measurement experiment was conducted from July 14 to Sep- 

 tember 1, 1971. The information collected in the western 

 Caribbean Sea included Lagrangian drifter data and density 

 data. These data were collected during two cruises, the first leg 

 lasting from July 14 to August 2 and the second leg from 

 August 10 to August 21. The second leg was shortened because 

 of a hurricane threat in the area. 



Figure 23 is a plot of the tracklines occupied during leg 

 1, and the approximate drift of the ship during the drogue 

 tracking operation. The type of information collected on each 

 line is also noted. Figure 24 presents the tracklines of leg 2. 



The reduction of the data to a form suitable for interpre- 

 tation has been completed. The analytical methods developed 

 will be applicable to other Lagrangian drifter studies planned 

 by this laboratory. 



The primary navigation fixes were reviewed to eliminate 

 spurious satellite positions. The satellite data were then used to 

 calibrate the 15-minute Omega fixes by first determining the 

 average difference between concurrent satellite and Omega po- 

 sitions and then by applying this difference to all Omega fixes. 



A further edit was performed to eliminate those spurious 

 Omega rates that were not found during the first iteration. 

 Drogue positions relative to the ship were converted to geo- 

 graphic positions by a program developed at AOML. 



The density data were obtained with a conductivity-tem- 

 perature-depth sensor, which was used operationally for the 

 first time on this cruise. Shipboard reviews of the salinity data 

 indicated a discrepancy between historical salinity values and 

 those being collected. This necessitated a calibration of the 

 instrument for what appeared to be a pressure effect on the 

 conductivity sensor. 



The expendable bathythermograph (XBT) and mechani- 

 cal bathythermograph (MET) analogs were edited to eliminate 

 bad traces. Temperature values obtained from both systems were 

 compared to conductivity-temperature-depth (CTD) tempera- 

 ture values, and neither system exhibited any systematic differ- 

 ences from the latter data. 



A report describing in detail the analysis techniques that 

 were applied to the data has been written for potential users of 

 these data. This report as well as the data may be obtained 

 from NODC. The data summary will be published in a NOAA 

 series and will be available from NTIS. 



Organization: NOAA/AOML 



Investigator: D. Hansen 



Project Title: Large-Scale Measurements of the Antilles 

 Current 



Grant No.: AG-253 



During the past year it has been possible to initiate what 

 is probably the largest scale Lagrangian measurement project 

 ever conducted on the ocean currents. This was made possible 

 through collaboration with NASA and the French Centre Na- 

 tional d'Etudes Spaciales (CNES) from which AOML ob- 

 tained the use of five transponder packages designed for use in 

 the French HOLE constant-level balloon experiment. The 

 packages were installed in five 12.5-meter aluminum spar 

 buoys and deployed between 23.5 °N and 28.0°N along 67 °W 

 (between Bermuda and Puerto Rico) in mid-September to 

 obtain information on surface currents in the same area as the 

 MODE-I experiment and in the Antilles Current, generally. 



It was judged from inferences based upon pilot chart data 

 that it might be possible to retrieve the buoys in the Cape 

 Hatteras/Bermuda/Nova Scotia triangle shortly before the sat- 

 ellite project (and associated tracking operations) terminated 

 at the end of December 1972. The points of deployment and 

 buoy trajectories for the first 7 weeks of the experiment are 

 shown in figure 25. 



It soon became apparent that the trajectories were so 

 unlike indications from the pilot charts that the plan for re- 

 covering the buoys was inadequate. Fortunately, the lifetime of 

 the project was extended 6 months — to June 30, 1973. Buoy 2 

 was recovered for engineering evaluation in mid-December. 

 The attached parachute drogue and all other rigging hardware 

 were in near-perfect condition. The transponders on buoys 1 

 and 3 had failed, however, and the buoys were lost. 



At the end of February, buoys 4 and 5 were still func- 

 tioning satisfactorily in the Antilles Current. Movement during 

 the last 3 months has been characterized by steady cyclonic 

 eddying of a time scale of about 1 month or longer. After 

 nearly 6 months, these buoys were less than 290 kilometers west 

 of their deployment longitude. The variability of movement of 

 these buoys is so great relative to the mean motion and the 

 difference between buoys so great that the previously planned 

 streamline analysis now appears to be inappropriate or impos- 

 sible, except in a negative sense. The observations already 

 negate, for example, the existence of an Antilles Countercur- 

 rent. The most meaningful result to be obtained from the 

 observations will probably be a determination of the statistical 

 structure of surface currents in the region, such as the correla- 

 tion length for deep currents that plays a key role in design of 

 the MODE-I array. 



The following data were submitted to NODC from the 

 Lagrangian Current Measurement Project NSF Grant No. 

 AG-235. NODC Accession Number 720922. 



Ship Cruise 



DISCOVERER RP-9D1-71 

 RESEARCHER RP-9-RE-71 



The following data were submitted to NODC from the 

 NOAA-AOML Air-Sea Interaction and Mixed Layer Project, 

 NSF Grant No. AG-253. NODC Accession Number 730598. 



Ship Cruise Data Type No. Records 



DISCOVERER RP-ll-Dl-71 XBT 125 



25 



