Figure 22. — Marsden squares in which XBT data have been collected during 1969-1973 by ships of opportunity. 



currents and winds consisted of a burst of six samples recorded 

 every 3.75 minutes; each of the six samples, consisting of 

 speed, compass, and vane, was measured at 4.95-second inter- 

 vals. 



Organization: NOAA/AOML 



Investigator: H. Mofjeld 



Project Title: Circulation Studies for CICAR: Tides in the 

 CICAR Region 



Grant No.: AG-253 



NOAA's Atlantic Oceanographic and Meteorological 

 Laboratories (AOML) has continued its research into the 

 distribution and dynamics of the tides in the Caribbean Sea 

 and the Gulf of Mexico. In addition, field experiments on tides 

 outside the Cooperative Investigation of the Caribbean and 

 Adjacent Regions (CICAR) area and for longer period mo- 

 tions have been carried out or are in preparation. 



To help define the positions of amphidromes in the Carib- 

 bean Sea, a deep-sea tide gage was deployed from May 1972 

 to November 1972 (16°32.5'N, 64°52.9'W) at a depth of 

 3,970 meters. The pressure record, probably the longest ever 

 obtained from a self-recording gage in deep water, is useful not 

 only as a lengthy record of tides with a high signal-to-noise 

 ratio but also in the study of longer period pressure fluctua- 

 tions. Analyses are being carried out both by NOAA scientists. 



using harmonic techniques, and by scientists at Nova Univers- 

 ity using the response method. 



A gage was deployed in the Gulf of Mexico (24°46.1'N, 

 89°38.9'W, at a depth of 3,460 meters) during November 

 1972. The gage was implanted in deep water to measure the 

 daily dominant tidal constituents of the Gulf and to determine 

 whether the semidaily tides have amphidromes. The gage, re- 

 covered during January 1973, operated for 3 months, and the 

 record is now being analyzed. 



The focus of the international deep-sea tides program has 

 been changed from studies on the amphidromes to studies of 

 several "action centers" and tide modifications on the conti- 

 nental margins. AOML is modifying its tide project in line 

 with these new goals. 



To understand how tides in the open ocean are related to 

 coastal observations, it has become evident that the behavior 

 of the tides on the continental shelves must be understood. To 

 study the tides on the shelf, the tide group at AOML deployed 

 tide gages with current meters off North Carolina at 

 34°09.3'N, 75 = 37.5'W (27 meters): 35°55.5'N, 76°37.3'W 

 (43 meters); and 32°41.5'N, 75°37.5'W (3,350 meters). 

 These instruments, which were deployed during July 1972 and 

 recovered during August 1972, recorded not only the transi- 

 tion of the tides from the open ocean toward the shore but also 

 currents and temperature changes due to meanderings of the 

 Gulf Stream. 



24 



