Expendable Bathythermograph Observations from 

 the NMFS/MARAD Ship of Opportunity Program 



for 1972 



STEVEN K. COOK 1 



ABSTRACT 



Results of the second year oi operation of the NMFS/MARAD Sliip of Opportunity Program are presented 

 in the form of vertical distributions of temperature and horizontal distributions of sea surface salinity and 

 temperature. Operational and data management procedures also are discussed. 



INTRODUCTION 



In midyear of 1970 a cooperative expendable bathythermo- 

 graph (XBT) program was initiated betveen the National 

 Marine Fisheries Service (NMFS) and the Maritime Admini- 

 stration (MARAD) of the U.S. Department of Commerce. 

 The program, conducted in support of the Marine Resources 

 Monitoring Assessment and Prediction Program of NMFS, 

 involved the use of Maritime Cadets from the Kings Point 

 Maritime Academy to gather XBT data on board various 

 merchant ships along the east and Gulf coasts of the United 

 States. The objective of this cooperative program was to 

 identify and describe seasonal and year-to-year variations of 

 temperature and circulation in major currents of the tropical 

 Atlantic, Caribbean Sea, Gulf of Mexico, and western North 

 Atlantic, utilizing merchant ships as relatively inexpensive 

 platforms for the collection of data. 



The processed data were used to construct vertical 

 sections of temperature and horizontal plots of sea surface 

 temperature and salinity. The final form of the vertical and 

 horizontal sections (Figs. 1-81) are printed in this report. 



Approximately 75 more XBT drops and associated surface 

 data were collected but are not represented in this report 

 because the observations were much too scattered in time 

 and space to be formed into transects. All data collected, 

 whether represented in this report or not, were archived by 

 the National Oceanographic Data Center (NODC) and are 

 available to interested persons through the NODC, Washing- 

 ton, D.C. 20235. 



Further details concerning the acquisition or processing of 

 data from the cruises considered here can be obtained from 

 the author. 



AREAS OF STUDY 



Ship routes were selected to obtain regular sampling in 

 the most dynamic areas of the Gulf of Mexico, Caribbean 

 Sea, and western tropical Atlantic Ocean; namely, the 

 Yucatan Channel, Straits of Florida, and the Antilles, 

 Equatorial, and Guiana currents. Repeated coverage is 

 important for comparative analysis, so ships with the most 

 regular schedules were chosen. 



' Atlantic Environmental Group. National Marine Fisheries Service, 

 NOAA, R.R. 7A, Box 522-A, Narragansett, RI 02882. 



DATA ACQUISITION AND PROCESSING 



Subsurface temperature data were obtained by use of 

 Sippican XBT systems. At the same time surface water 

 samples were collected with bucket thermometer units for 

 later anaiy.sis to determine salinity. This procedure also 

 provided a surface reference temperature necessary for the 

 calculation of surface density or sigma-f. The surface water 

 samples were analyzed on shore using a Beckman inductive 

 saHnometer calibrated with standard (Copenhagen) water at 

 least once per 30 samples. 



The XBT traces from approximately the first half of the 

 year were digitized, key punched, and quality controlled by 

 NMFS personnel. Those from the balance of the year were 

 digitized and key punched by NODC personnel. The data 

 from both halves of the year were then submitted to NODC 

 for further processing and listing. 



DISCUSSION 



This second year of operation of the NMFS/MARAD Ship 

 of Opportunity Program was highlighted by two events. The 

 first was the commencement of involvement of NODC in the 

 processing of the Ship of Opportunity data. Programs are 

 being developed at NODC to process these data from the 

 analog traces to computer plots within a 10- to 14-day 

 turnaround time. While this program is not completely 

 operational at this writing, it is expected to be in time for the 

 1973 report. 



The second event was the increase in data collected by the 

 MARAD cadets. The utilization of two more ships, one out of 

 New York and one out of New Orleans, allowed for a 25% 

 increase in data collected over 1971 . The addition of two ships 

 yielded a total of six (three out of New York and three out of 

 New Orleans) involved with the program. 



Future program improvements should take the form of 

 more intense coverage over a smaller geographical area. 

 Discussions held in late 1972 led to a decision to reduce the 

 area to be covered and increase the density of XBT drops in 

 1973. This should yield data more useful for fisheries 

 research. 



ACKNOWLEDGMENTS 



Appreciation is extended to the Maritime Academy Train- 

 ing Representatives in New York and New Orleans, M. 



