中文摘要：

利用中国科学院大气物理研究所大气科学和地球流体力学数值模拟国家重点实验室（LASG）新一代耦合气候模式（FGOALS）进行了气候异常季节后报试验,通过对1982—2005年7个个例的分析,探讨了厄尔尼诺衰减年夏季东亚大气环流和降水异常发生的物理机制。分析结果表明：FGOALS可以模拟出厄尔尼诺衰减年夏季相关气候场的异常态特征,表现为在西北太平洋为负海温异常,在热带印度洋为正海温异常,从而导致西北太平洋地区大气中低层异常反气旋环流的维持,其反气旋的西南部及西部的偏南及西南气流造成中国长江中下游地区降水的异常增多。在提前3—9个月的预测模拟中,模式可以模拟出气候场的异常演变,随着预测时间的延长,产生局地耦合的西北太平洋海表温度异常信号变弱,使得模拟出的西北太平洋反气旋异常偏弱、中心东移,从而导致影响东亚降水的气候场的异常变弱,降水异常区偏东。模拟结果也揭示出,西北太平洋海表温度负异常是厄尔尼诺异常信号的转换模态,并且,由于局地海-气相互作用,热带海温异常信号可以持续到第2年夏季,从而引起东亚大气环流和降水异常。对于东亚降水的季节预测出现误差可能是模式对ENSO的模拟偏差造成的,随着预测时间延长,模式模拟的厄尔尼诺信号偏弱,这将使得海表温度异常偏弱,同时相关物理场的异常响应也减弱。

英文摘要：

The present work evaluates the simulations of rainfall responses over East Asia to the El Nio in a coupled model（FGOALS） and discusses the possible effect of El Nio on the East Asian rainfall during its decaying summer in terms of the seasonal forecast.The results show that the FGOALS model can reasonably simulate the El Nio-related climate anomalies during the decaying summer,such as the negative sea surface temperature anomalies（SSTA） in the western North Pacific（WNP）,the anomalous anticyclone over the WNP,and increasing rainfall over the middle and lower reaches of the Yangtze River.For 1 to 3 leading season forecast simulation,the model can roughly simulate the evolution of climate anomalies.However,the longer the predicting time is,the weaker the SSTA and anomalous anticyclone over the WNP are,which tends to cause the decreased rainfall over East Asia.The simulations reveal that the SSTA associated with El Nio can remain for about three seasons.This provides a solid basis for the rainfall forecast over East Asia.In addition,it is suggested that the error of simulated East Asian rainfall may be related to the departure of ENSO simulation due to model bias.