基于CMIP5资料的热带大洋非均匀增暖及其成因的分析

摘要

Using the global monthly mean datasets from the Coupled Model Intercomparison Project Phase 5 (CMIP5), the characteristics of non-uniform sea surface temperature warming over the tropical Pacific, Indian and Atlantic oceans and its causes are analyzed. We use various meteorological statistical methods, such as synthetic analysis and correlation analysis. Multi-model results show that annual mean spatial distributions of the variation in SST exhibit non-uniform patterns over the three tropical oceans under global warming. However, the causes responsible for these non-uniform patterns are quite different. The oceanic dynamic processes play a leading role in the equator and over the area north of the equator in the tropical Pacific Ocean, while the atmospheric thermal effect becomes more important over the area south of the equator. In addition, the oceanic upwelling/downwelling processes play different roles in the eastern and western tropical Pacific. For most part of the tropical Indian Ocean, variation in sea surface temperature is not well explained by the air-sea heat fluxes and oceanic dynamics such as upwelling/downwelling, and temperature advection also plays an important role. For the tropical Atlantic Ocean, the SST variability in the area near the equator mainly results from oceanic dynamics such as temperature advection and upwelling/downwelling. Temperature advection plays a leading role in the variation of sea surface temperature north of the equator, while upwelling/downwelling plays a dominant role south of the equator.%利用第五次耦合模式比较计划(coupled model intercomparison project phase 5,简称CMIP5)中的月平均资料,基于合成分析、相关分析等现代气象统计方法,对热带太平洋、印度洋和大西洋年平均海温增暖不均匀特征及其成因进行分析。9个海洋模式集合的平均结果表明：在全球增暖背景下,3个热带大洋的海温增暖均表现出不均匀性,且增暖原因存在较大差异。热带太平洋赤道及其以北地区以海洋动力作用为主,赤道以南地区则以大气热力作用为主,而且海水上翻/下沉运动对海温增暖的作用在东、西太平洋之间存在明显差异；热带印度洋大面积海域的海温变化难以通过海气热通量交换来解释,海水上翻/下沉运动与温度平流对海温增暖的作用比较一致(二者同时利于海温增暖)；热带大西洋赤道附近地区的海温增暖是表层温度平流和上翻/下沉运动共同作用的结果,赤道以北的大西洋海温变化则以温度平流的作用为主,而赤道以南的大西洋海温的变化主要是海水上翻/下沉作用引起的。