利用全球中期数值预报谱模式,通过在海表温度气候态上叠加不同扰动的方法,研究了不同季节月尺度大气环流对海表温度变化的响应特征及机理。结果表明,大气响应首先出现海表温度的高值区和海温扰动变化的大值区,其发展和演变还与大气环流的背景场有关,大气响应发展达到稳定的状态是沿南、北半球西风急流附近的纬向波状分布;在不同季节,对不同分布的海表温度变化,大气环流响应的速度不同,但在月尺度内大气响应都能达到最大值;相对于夏季,冬季大气响应最大值达到的高度更高,大气响应对扰动的形态更敏感。
Using the spectral forecast model with the global medium range, the response characteristics of monthly atmospheric circulation to SSTA (sea surface temperature anomaly) and the mechanism are in- vestigated. In order to detect the model response characteristic in different seasons, two sets of sensitivity numerical simulations are conducted. For each experiment, except for the control experiment that is per formed with climatological SST (sea surface temperature) for ocean boundary conditions, the other two in- tegrations forced with prescribed and random SSTA added to climatological SST. The simulated results show that atmospheric responses firstly generate in areas with high SST oceans and large disturbed SSTA oceans, and the development and evolution of atmospheric responses are related to the background of at- mospheric circulation. Furthermore, when the atmospheric responses in model come to a steady state, the simulated atmospheric responses are in zonal wavy distribution along westerly jet. During the different seasons, the speeds of atmospheric circulation response have the dissimilar SST distribution. However, both in winter and in summer, the size of responses can reach maximum within monthly time scale. In gen- eral, atmospheric responses are likely to be zonal wavy distributed after the forth pentad. Maximum value of atmospheric responses in winter reach higher altitude comparing to that in summer, and this may be caused by the fact that deep westerlies in winter are more convenient for the vertical spread of Rossby wave. And the atmospheric responses in model are more sensitive to distribution of perturbation in winter then in summer. In extended-range, atmospheric responses depend more on the background of atmospheric circulation namely atmospheric internal dynamic than boundary conditions.