southward flow between the Galapagos Islands and Ecuador 

 was confined to a shallow surface layer 10 to 25 m thick, and 

 changes in the subsurface layers also were quite different from 

 what is normally expected. The density surfaces along both 

 the Equator and the coasts of Ecuador and Peru were abnor- 

 mally depressed in the upper 200 m, indicating a very strong 

 eastward flow of the Equatorial Undercurrent and a southward 

 flow along the coast. This anomalous flow regime seems to 

 play an important role in El Nifio dynamics. 



Although observations during the first cruise revealed 

 features of a developing El Nifio, the data of the second cruise 

 documented that it was short-lived. During April and May, 

 with the re-establishment of the southeast trade winds, and 

 upwelling along the coast and Equator, the cool waters of the 

 Peru-Chile Current replaced the warm waters found 2 months 

 earlier (fig. 6b). The subsurface flow eastward along the 

 Equator had weakened, and along the coast the subsurface 

 flow was no longer to the south. The large change in sea surface 

 temperature between the time of the two cruises (fig. 6c) illus- 

 trates the rapid and intense variation in the ocean in this region. 

 The change in sea surface temperature within this 2-month 

 period (greater than 5°C in some areas) was as large as the 

 mean seasonal range indicated by climatological atlases. 



Although 1975 was not the year of a catastrophic El Niiio 

 of long duration, an El Nino event continued to develop from 

 January through March. Cruises of previous expeditions never 

 covered the entire affected area. Consequently, much was 

 learned about the dynamics of El Nifio events — particularly 

 the generation of large temperature and circulation anomalies 

 and their rapid dissipation. 



TRANSPAC 



The TRANSPAC program uses observers aboard com- 

 mercial ships (platforms-of-opportunity) that regularly cross 

 the Pacific Ocean. Data obtained within the area from 30° 

 to 50 N and 140 W to 150"E, which was continuously 

 monitored for the first time, show significant results. One 

 observed phenomenon was the rapid variability of the main 

 thermocline over this large area during a relatively short period 

 (fig. 7). Along two nearly parallel ship tracks separated by 

 about 150 km (Taft and Van Buren voyages), observations 

 were obtained within a 2-day period. Depths of the 10° and 

 12°C isotherms (which were selected as representative of the 

 main thermocline) agreed very well along the two tracks despite 

 their 150-km separation, indicating a marked uniformity in 

 depth of the main thermocline over the large area traversed 

 by the ships. Along two nearly parallel ship tracks separated 

 by only 20 km (McKinley and Van Buren voyages), obser- 

 vations were obtained about 12 days apart. Over this period, 

 the 10" and 12"C isotherms were observed to descend about 

 50 meters, indicating a rapid change in depth of the main 

 thermocline. This change was attributed to passage of a major 

 winter storm slightly north of the two tracks during the 12-day 

 period. An Anomaly Dynamic Study (ADS) has been initiated 

 to investigate such changes in thermocline structure. 



NORPAX Data 



NORPAX data and information available from NODC 

 include the following. 

 NODC Accession No.: (none) 

 Organization: University of Hawaii 

 Investigator: K. Wyrtki 



Grant No.: IDO75-06468 



NORPAX/El Niiio Watch preliminary data report, 

 Volumes I and II, RV Moana Wave, Legs 1 and 2, February 

 11 to March 31, 1975. Physical, chemical, and biological data: 

 93 SDT profiles, 45 Niskin casts, 432 XBTs, 97 zooplankton 

 net tows, 74 meteorological balloon soundings, and current 

 meter data. (Data report prepared by GEOSECS Operations 

 Group, Scripps Institution of Oceanography.) 



NODC Accession No.: (none) 

 Organization: University of Hawaii 

 Investigator: K. Wyrtki 

 Grant No.: IDO75-06468 



NORPAX/El Nino Watch preliminary data report, 

 Volume III, RV Moana Wave, Legs 3 and 4, April 17 to May 

 27, 1975. Physical, chemical, and biological data: 97 STD 

 profiles, 47 Niskin casts, 411 XBTs, 93 zooplankton net 

 trawls, 67 meteorological balloon soundings, and 74 tritium 

 samples. 



NODC Accession No.: 76-0615 



Organization: NOAA National Marine Fisheries Service, 



La Jolla, Calif. 

 Investigator: D. McLain 

 Grant No.: OCE 75-23357 



NORPAX Pacific Ships of Opportunity data: XBTs from 

 6 ships, 97 cruises; 1,254 lowerings, August to December 1974, 

 and 1,481 lowerings, January to July 1975, magnetic tape. 



NODC Accession No.: 74-00748 



Organization: NOAA National Marine Fisheries Service, 



La Jolla, Calif. 

 Investigator: J. F. T. Saur 

 Grant No.: AG-256 



NORPAX data: 1,460 digitized XBT drops from the 

 Pacific Ships of Opportunity Program during the period April 

 1973 to July 1974. 



NODC Accession No.: 75-0530 



Organization: Scripps Institution of Oceanography 



Investigator: R. T. Wert, NORPAX Data Manager 



NORPAX data: One magnetic tape containing observa- 

 tions from 23 bumble bee buoys (at 1-hour intervals). Param- 

 eters are: 1) air temperature, 2) wind speed and direction, 

 3) wind transport. 4) barometric pressure, 5) sea temperature 

 at maximum of 12 depths, 6) pressures at two depths, 7) solar 

 radiation, and 8) mooring line tension. Data were collected 

 from 6 buoys during May 1964 to February 1967, and from 

 17 buoys during February 1968 to February 1973. 



NORPAX Bibliography 



Barnett, T. 1972: Observations of wind wave generation and 

 dissipation in the North Sea: implications for the offshore 

 industry. Fourth Annual Offshore Technology Conference, 

 May 1-3, 1972, Houston, Tex., Paper No. OTC 1516, 

 8 pp. 



Barnett, T. 1972: The North Pacific Experiment: a study of 

 large scale ocean and atmosphere fluctuations in the Pacific, 

 WMO Reports on Marine Affairs. Rpt. #7, Means of 

 Acquisition and Communication of Ocean Data, Vol. II, 

 Proc. WMO Tech. Conf., Tokyo, Japan, October 2-9, 

 1972, pp. 333-344. 



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