Southward surface flow in the central South Pacific
Author(s)
Kern E. Kenyon
ABSTRACT
A large-scale surface flow with a southward component is proposed for the central South Pacific Ocean based on an interpretation of existing closely spaced and accurately measured temperatures and salinities along two latitudes in two different southern hemisphere winters: 28o S (Scorpio) and five degrees south of that (WOCE). Such a southward flow is not predicted from theory nor is it shown on current charts and globes. The observed longitudinal maximum in surface temperature along 28o S is centered around 130o W and has an amplitude of at least 5o C and an east/west range of about 60o of longitude. This striking feature is most easily explained by horizontal transport from latitudes closer to the equator. Since temperature atlases show that equatorial surface temperatures are always highest in the west, the origin of the warm water probably is toward the western side of the ocean as well. Thus the surface flow surrounding the longitudinal temperature maximum should be directed to the southeast. Where the surface temperatures are maximum the mixed layer depths are relatively large in a convex downward lens with maximum depths of 100 m; a correlation that is consistent with warm water moving south and being cooled from above. Salinities are maximum near the temperature maximum, also suggesting that the source of the surface flow is at low latitudes, where evaporation is usually expected to exceed precipitation. It is conjectured that the large-scale southeastward flow of the South Pacific is the analogue of the northeastward wide warm current off California documented over 30 years ago.
A large-scale surface flow with a southward component is proposed for the central South Pacific Ocean based on an interpretation of existing closely spaced and accurately measured temperatures and salinities along two latitudes in two different southern hemisphere winters: 28o S (Scorpio) and five degrees south of that (WOCE). Such a southward flow is not predicted from theory nor is it shown on current charts and globes. The observed longitudinal maximum in surface temperature along 28o S is centered around 130o W and has an amplitude of at least 5o C and an east/west range of about 60o of longitude. This striking feature is most easily explained by horizontal transport from latitudes closer to the equator. Since temperature atlases show that equatorial surface temperatures are always highest in the west, the origin of the warm water probably is toward the western side of the ocean as well. Thus the surface flow surrounding the longitudinal temperature maximum should be directed to the southeast. Where the surface temperatures are maximum the mixed layer depths are relatively large in a convex downward lens with maximum depths of 100 m; a correlation that is consistent with warm water moving south and being cooled from above. Salinities are maximum near the temperature maximum, also suggesting that the source of the surface flow is at low latitudes, where evaporation is usually expected to exceed precipitation. It is conjectured that the large-scale southeastward flow of the South Pacific is the analogue of the northeastward wide warm current off California documented over 30 years ago.
Cite this paper
Kenyon, K. (2012) Southward surface flow in the central South Pacific. Natural Science, 4, 819-824. doi: 10.4236/ns.2012.411109.
Kenyon, K. (2012) Southward surface flow in the central South Pacific. Natural Science, 4, 819-824. doi: 10.4236/ns.2012.411109.
References
[1] Scripps Institution of Oceanography (1969) Physical and chemical data from the Scorpio expedition in the South Pacific aboard USNS Eltanin, cruises 28 and 29, 12 March-31 July 1967. Scripps Institution of Oceanography and Woods Hole Oceanographic Institution, La Jolla. [2] Kenyon, K.E. (1981) A shallow northeastward current in the North Pacific. Journal of Geophysical Research, 86, 6529-6536. HUdoi:10.1029/JC086iC07p06529UH [3] Kenyon, K.E. (1978) The surface layer of the eastern North Pacific in winter. Journal of Geophysical Research, 83, 6115-6122. HUdoi:10.1029/JC083iC12p06115U [4] U S Hydrographic Office (1944) World atlas of sea surface temperatures. 2nd Edition, U S Navy Hydrographic Office, Washington DC. [5] Kenyon, K.E. (1999) North pacific high: An hypothesis. Atmospheric Research, 51, 15-34. HUdoi:10.1016/S0169-8095(98)00110-0U
[1] Scripps Institution of Oceanography (1969) Physical and chemical data from the Scorpio expedition in the South Pacific aboard USNS Eltanin, cruises 28 and 29, 12 March-31 July 1967. Scripps Institution of Oceanography and Woods Hole Oceanographic Institution, La Jolla. [2] Kenyon, K.E. (1981) A shallow northeastward current in the North Pacific. Journal of Geophysical Research, 86, 6529-6536. HUdoi:10.1029/JC086iC07p06529UH [3] Kenyon, K.E. (1978) The surface layer of the eastern North Pacific in winter. Journal of Geophysical Research, 83, 6115-6122. HUdoi:10.1029/JC083iC12p06115U [4] U S Hydrographic Office (1944) World atlas of sea surface temperatures. 2nd Edition, U S Navy Hydrographic Office, Washington DC. [5] Kenyon, K.E. (1999) North pacific high: An hypothesis. Atmospheric Research, 51, 15-34. HUdoi:10.1016/S0169-8095(98)00110-0U