印度洋海气相互作用对热带夏季大气环流气候态的影响

利用分辨率较高的SINTEX-F(Scale INTeraction EXperiment-FRCGC) 海气耦合模式, 进行多组长时间积分模拟和理想试验, 分析研究热带印度洋海气耦合对夏季大气环流气候态的影响。主要结果有: (1) 热带印度洋海气相互作用使热带东印度洋产生明显的东风变化, 使热带中西太平洋赤道北部产生气旋性切变变化。 (2) 印度洋海气相互作用对大气环流气候态的影响绝大部分由于大气对海气相互作用的响应存在年际变化正负距平不对称性造成, 这种年际变化不对称性包括正偶极子与负偶极子的不对称、 海盆宽度正异常与海盆宽度负异常的不对称。 (3) 年际和季节内两种时间尺度海气相互作用对印度洋关键区大气环流平均态都有影响, 约各占60%、 40%; 季节内尺度海气相互作用对太平洋近赤道区大气环流平均态有重要影响; 年际尺度海气相互作用对太平洋赤道外地区大气环流平均态有重要影响。热带印度洋年际尺度、 季节内尺度海气相互作用对大气环流气候态的影响, 都存在年际变化以及年际变化正负距平不对称性。这两种尺度海气相互作用主要通过年际变化正负距平不对称性而对大气环流平均态产生影响。

Impact of Air-Sea Interactions over the Indian Ocean on the Climatological State of Tropical Atmospheric Circulation in Boreal Summer

The impact of air-sea coupling over the Indian Ocean on the climatological state of tropical atmospheric circulation in boreal summer is investigated by diagnosing the long-term simulations frorn the high-resolution SIN-TEX-F (Scale INTeraction EXperiment-FRCGC) coupled ocean-atmosphere model The main conclusions are listed as below. (1) Air-sea interactions over the tropical Indian Ocean strengthen easterlies over the tropical eastern Indian Ocean, and induce cyclonic shearing circulation over the north of western and central Pacific. (2) The impact of air-sea interactions on the climatological mean state over the Indian Ocean is primarily attributed to the asymmetric at-mospheric response to positive and negative Indian Ocean dipole modes and the asymmetric response to positive and negative basin-wide modes over the tropical Indian Ocean. (3) Air-sea interactions on both interannual and intrasea-sonal timescales contribute to the change of the climatological mean state over the Indian Ocean; they account for 60%(interannual timescale) and 40%(intraseasonal timescale) respectively. While the impact of the intraseasonal air-sea interaction on the mean circulation is more important in the equatorial Pacific region, the impact of the intera-nnual air-sea interaction is more important in the off-equatorial Pacific region. The impact of air-sea interactions on both the timescales exhibits a significant interannual variation and amplitude asymmetry between the positive and negative anomalies.