2. Directly measured currents will be compared with 

 geostrophic calculations based on shipboard hydrographic 

 data. 



3. Relative geostrophic currents based on temperature 

 observations from aircraft and ships will be compared 

 with those based on complete hydrographic data. 



4. The feasibility of monitoring upper layer equatorial 

 currents using drifting buoys and moored current meters 

 will be determined. 



5. The feasibility of monitoring thermal structure and, 

 indirectly, transport using XBT's dropped from commer- 

 cial vessels and /or aircraft will be examined. If adequate 

 coverage could be achieved, this would be one of the 

 most economical of all monitoring techniques. 



6. Atmospheric observations from island stations and 

 ships will be used to relate changes in the ocean and the 

 atmosphere. Island station and ships data are essential 

 to equatorial meteorology because of the vast expanses 

 of open sea. 



7. Sea level fluctuations, as measured from island tide 

 gauges, will be compared against geostrophically com- 

 puted and directly measured currents. Tide gauge records 

 provide the longest time series data related to current 

 fluctuations. 



During FGGE several countries in the Pacific area will 

 be carrying out equatorial observational programs. For ex- 

 ample, the French laboratory at New Caledonia intends to do 

 hydrographic sections and current measurements in the western 

 Pacific and the Japanese intend to do related work in the 

 western Pacific. A major part of the U.S. effort will be carried 

 out by NORPAX investigators. 



The fundamental conceptual framework or hypothesis of 

 the NORPAX Equatorial Program is that variations of large 

 scale zonal currents in the central tropical ocean, induced by 

 low frequency fluctuations in the trade winds, cause large 

 scale changes in the heat content of the upper layers of the 

 eastern tropical Pacific. This framework is subject to modifi- 

 cation as a result of pre-FGGE experiments, but a FGGE- 

 related observational program, based on that framework, has 

 already been tentatively outlined. The elements of that pro- 

 gram are (see fig. 14): 



1. Meridional hydrographic sections to monitor the den- 

 sity structure and, indirectly, the currents. 



2. Direct current observations, especially close to the 

 Equator where the computation of geostrophic currents 

 is not possible. 



3. General oceanographic observations from smaU boats 

 based at island stations. 



4. Observations of the thermal structure in the far 

 eastern equatorial Pacific where mid-ocean disturbances 

 eventually interact with the coast. This may be done 

 through a ships of opportunity program or through co- 

 operation with research institutes in Ecuador or Peru. 



The international cooperation option will be explored 

 by SCOR Working Group 47 on FGGE oceanography. 



5. The Intertropical Convergence Zone (ITCZ) is the 

 region where a major portion of the heat is supplied by 

 latent heat flux to the atmosphere. An experiment to 

 investigate the relationship between sea surface condi- 

 tions in the ITCZ and ocean-atmosphere interaction 

 might be performed during two periods when the con- 

 vergence zone is sharply defined and relatively stable in 

 position (January to February and May to June 1979). 



The knowledge gained during FGGE will be applied to 

 the design of a continuing equatorial Pacific monitoring net- 

 work. This network will assist in achieving NORPAX long 

 range goals. 



NORPAX Data 



NORPAX data are available from NODC as foUows: 



NODC Accession No.: 77-0162 



Organization: Scripps Institution of Oceanography 



Investigators: W. J. Emery and R. T. Wert 



Grant No.: NSF/OCE74-24583 



Project: Mean T S Curves in the Pacific 



Data: These data result from processing all NODC holdings of 

 station data and BT data in the Pacific. The processed re- 

 sults are mean T S curves for the Pacific Ocean. They 

 were submitted on NODC-compatible tape and are also 

 available as a published data report. 



NODC Accession No.: Held at National Climatic Center 



Organization: University of Hawaii 



Investigator: J. C. Sadler 



Grant No.: NSF/GX-42007 



Project: Pacific Cloud Atlas 



Data: Daily values of total cloud cover in OCTAS for each 

 2'/2° lat. by 2'/2° long, grid square over the Pacific Ocean 

 for the area 30° S to 60° N and 105° E to 75° W, derived 

 from daily nephanalysis prepared from meteorological satel- 

 lites. The data were submitted on magnetic tape. 



NORPAX BibUography 



Harnett, T. P., M. H. Sessions, and P. M. MarshaU. 1976. Ob- 

 servations of thermal structure in the central Pacific. 

 NORPAX SIO Ref. Ser. 76-19, Scripps Inst. Oc, 48 p. 



Harnett, T. P., and J. D. Ott. 1976. Average features of the 

 subsurface thermal field in the central Pacific. SIO Ref. 

 Ser. 76-20, Scripps Inst. Oc, 13. 



Dickson, R., and J. Namias. 1976. North American influences 

 on the circulation and climate of the North Atlantic sec- 

 tor. Monthly Weath. Rev. 104:1255-1265. 



Emery, W. J., and L. Magaard. 1976. Haroclinic Rossby 

 waves as inferred from temperature fluctuations in the 

 eastern Pacific. J. Mar. Res. 34:365-385. 



Emery, W. J., and R. T. Wert. 1976. Mean TS curves in the 

 Pacific and their application to dynamic height computa- 

 tions. NORPAX, SIO Ref. Ser. 76-6. Scripps Inst. Oc, 

 125 p. 



Friehe, C. A., and K. F. Schmitt. 1976. Parameterization of 

 air-sea interface fluxes of sensible heat and moisture by 

 the bulk aerodynamic formulas. J. Phys. Oc. 6:801-809. 



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