OCTOBER 1, 1999

Surface Heat Budgets and Sea Surface Temperature in the
Pacific Warm Pool During Toga Coare

The western equatorial Pacific is a region of high water
temperature, strong convection and heavy rainfall, and supplies a huge
amount of energy for atmospheric circulation. The variation of sea surface
temperature in this region is small but has a large impact on the global
climate. Solar radiation received at the surface increases the surface
water temperature, while the heat losses at the surface due to infrared
radiation, evaporation and sensible heat reduce the water temperature.
Because atmospheric and oceanic data in this region are scarce, the
mechanisms causing the sea surface temperature to change is not well
understood.

To understand the causes of the temperature change in the western
equatorial Pacific, The surface fluxes of solar radiation, infrared
radiation, latent heat (due to evaporation), and sensible heat are derived
from satellite radiation measurements. The results are validated against
the surface measurements conducted during the intensive observing period
(November 1992-February 1993) of the Tropical Ocean Global Atmosphere
(TOGA) Coupled Ocean-Atmosphere Response Experiment (COARE). One of the
goals of this international project was to better understand the mechanism
of the change in the sea surface temperature. It is found that, during
these four months, the mechanisms moderating the sea surface temperature
are different between the regions north and south of the equator. In the
northern warm pool, the net surface heating and water temperature have a
strong seasonal variation, which is primarily influenced by evaporative
cooling. In the southern warm pool, the net surface heating and water
temperature undergo large intraseasonal variations (40-50 day oscillations)
during the same period, and the solar radiation is the dominating factor in
influencing the variation of sea surface temperature.

Reference: A paper entitled, "Surface Heat Budgets and Sea Surface
Temperature in the Pacific Warm Pool During TOGA COARE" by Shu-Hsien Chou,
Wenzhong Zhao, and Ming-Dah Chou, is accepted for publication in the
Journal of Climate.