热带海气相互作用对大气BSISO年际振荡的影响

利用卫星观测OLR资料以及海气耦合数值模拟试验结果,从每年波-频分析结果提取了各种传播模态的强度指数序列,分析了热带北半球夏季季节内振荡(BSISO)各种传播模态的年际变化谱特征,探讨了热带各海区海气相互作用对其影响。主要结果如下:赤道外西传波和印度洋北传波以准2 a为显著振荡周期,赤道东传波、南海北传波和西太平洋北传波则都包含准2 a和准5 a两种周期,南海北传波是5种指数中惟一以准5 a为最主要周期振荡的模态。热带印度洋、西太平洋、东太平洋各海区海气相互作用对各指数准2 a振荡、准5 a振荡既有加强作用,也有削弱作用。各海区比较而言,对赤道东传波准2 a和准5 a振荡、南海北传波准2 a和准5 a振荡起最大加强作用的是西太平洋海区海气相互作用;对赤道外西传波准2 a振荡、西太平洋北传波准2 a和准5 a振荡起最大加强作用的是印度洋海区海气相互作用。

Effects of air-sea interaction on the interannual oscillations of atmospheric boreal summer intraseasonal oscillations over the tropical Ocean

Intensity index series of different propagation mode are abstracted from the wavenumber-frequency analysis result of every year, the interannual oscillation spectrum characteristics of atmospheric boreal summer intraseasonal oscillations are analyzed and the effects of air-sea interaction on the interannual oscillations of atmospheric boreal summer intraseasonal oscillations over the tropical ocean are investigated using observational OLR and outcome of air-sea coupling numerical simulation experiments.It is shown that the distinct oscillation period of poleward westward propagation and northward propagation in the Indian Ocean is quasi-biannual while both of quasi-biannual and quasi 5-year are contained by eastward propagation of equator, northward propagation in South China Sea and northward propagation in western Pacific.The northward propagation in South China Sea is the only mode which holds the main oscillation period of quasi 5-year.There are reinforcing and weakening effects of air-sea interactions on the intensity of quasi-biannual and quasi 5-year oscillations of different index.By comparing different oceans, the most strengthen effect on quasi-biannual and quasi 5-year oscillations of eastward propagation, or quasi-biannual and quasi 5-year oscillations of northward propagation in South China Sea, is the air-sea interaction over western Pacific; the most strengthen effect on quasi-biannual oscillation of westward propagation, or quasi-biannual and quasi 5-year oscillations of northward propagation in western Pacific, is the air-sea interaction over the Indian Ocean.