Variability Of Heat Content In Southern Pacific And Study Of Decadal Variability

Based on the SODA and COADS, the variability of heat content for tropical and subtropical cells in the Southern Pacific have been studied. Circulation indices, thermal advection and wind stress curl that relate to heat content have also been studied. At the same time, In order to find the probable reasons that lead to decadal variability author analyze spacial distribution of sea temperature at different depth and different latitude in different time scale.The variabilities of heat content in the tropical, subtropical cells respectively dominated by interannual and decadal . As an open system, the variability of heat content not only affected by thermal advection, but also affected by interaction of air-sea. The sum of long-radiate, short-radiate, latent heat and sensible heat has more important affection than thermal advection in the subtropical cell; while in the tropical cell, the contribution of thermal advection is greater than interaction of air-sea. The two cells may be connected with mechanism of meridional overturning circulation.Using method of magnifying signal of climatic variability, and comparing spacial distribution of interannual variability with that of decadal variability, author have found that : variability of ENSO and decadal variability are connected with thermocline in the spacial distribution; they have similar horizontal distribution for equatorial sea. Warm phases of interanuual and decadal variability correspond to intensity of anomalous western wind above equatorial sea .The differences are just as following: anomaly of ENSO is connected with seasonal change, while decadal variability may don't relate to seasonal change. The spacial distribution of decadal variability between eastern equatorial Pacific and higher latitudes are out of phase. The reasons leading to warming of eastern equatorial pacific are greatly different: the SSTA of interannual variability is related to anomaly of zonal wind, while SSTA of decadal variability is connected with anomaly of meridonal wind.The probable reasons that may lead to decadal variability are analyzed throughthe view of interaction of aie-sea in large-scale time. The results show that : westerly belt and it's intensity in southern Indian ocean may result in warming of SST in subtropical cell of southern Indian ocean in decadal time scale, while it can result in cooling of SST of southern Pacific in the same latitude . Weakening of southern wind coming from Pacific in western shore of south American is good to warming of SST in eastern equatorial Pacific.