“暖池”表层对大气局地强迫的响应特征

THE CHARACTERISTICS OF "WARM POOL" SURFACE LAYER RESPONDING TO LOCAL ATMOSPHERIC FORCE

利用湍流动能（TKE）垂直混合模式和TOGA－COARE加强观测期的观测资料，对“暖池”上混合层的垂直混合过程进行数值试验和数值模拟，分析表层温度、盐度的变化特征。结果表明：TKE模式可以较好地模拟上混合层，尤其是表层温度、盐度对大气局地强迫的响应；太阳辐射是热源，感热、潜热通量等会造成“暖地”上混合层的温度降低，“暖池”对大气释放热量；降水有利于“淡水盖”形成和维持，从而使层结稳定，SST升高。但在气温低于海温时降水可使SST下降；风应力的垂直混合作用能使SST降低，但也会因造成海洋向大气输送热量减少而使SST上升。正是由于这几种局地强迫与SST相互作用形成一个负反馈系统，使“暖池”表层温盐具有季节内振荡的特性。

A numerical experiment of the vertical mixed process of 'warm pool' mixed layerwas made and the variation characteristics of surface layer temperature and sa1initywere analysed based on the vertical mixed model of the turbulent kinetic energyTKE model) and intensive observation data of TOGA-COARE. The results showthat the TKE model can simulate well the response of temperature and salinity inthe upper mixed layer especially in the surface layer to local atmospheric forcings.Solar radiation is heat source and sensible and latent heat fluxes can decrease thetemperature of the upper mixed layer, the 'warm pool' releases heat to atmosp-here. Precipitation is favourable to forming and maintaining a 'fresh water lid'so that stabilizes the stratification and increases SST, however, when air temperatureis colder than sea temperature, precipitation decreases SST. The vertical mixing dueto wind stress can cause SST decrease, but it can also redhce the heat flux from seato air so that SST increases. The interaction between local forcings and SST is anegative feedback system. The temperature and salinity of the surface layer haveintraseasonal oscillation characteristics.