Observing the coupling effect between warm pool and “rain pool” in the Pacific Ocean

Traditionally, the tropical zone is known as the “heat reservoir” of the ocean and the “firebox” of the atmosphere. The western equatorial Pacific has been identified as both the warmest portion of the heat reservoir, named “warm pool” (WP), and the hottest portion of the firebox where a huge amount of precipitation-induced latent-heat release is accumulated. The latter mirrors a fact that the western tropical Pacific is also the wettest area on the globe, termed “rain pool” (RP), where the maximum annual precipitation is observed. The accumulation of continuous satellite data has reached a point that decade-long simultaneous observations of many important geophysical parameters have become available in recent years. One such example is the availability of a concurrent dataset of sea surface temperature, oceanic precipitation, and sea surface wind field for 1993–2002 derived from NOAA/AVHRR (Advanced Very High Resolution Radiometer), TOPEX/TMR (TOPEX Microwave Radiometer), and ERS-1,2/QuikSCAT, respectively. In the present study, this dataset is used to demonstrate and investigate the coupling and covarying effects of the Pacific WP and RP, leading to a number of interesting findings on their structural similarity, locational shift, phase lag, and evolutional coherency in association with the development of and the vacillation between El Niño and La Niña events.