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东亚季风区在年际尺度上存在显著的准两年振荡(TBO)周期,对我国气候异常有着重要影响.本文基于一套能够客观描述西太平洋副热带高压系统的重建指数,重点分析了东亚季风系统中的关键成员之一——西太平洋副热带高压(以下简称副高)的TBO特征及其与低纬地区海温与大气环流异常的关系.研究表明:(1)TBO作为副高一个重要的年际分量,在20世纪70年代末期表现出显著的转折特征,近30年副高TBO的变率比前30年显著增大,具有年代际尺度的变化.(2)副高TBO与几个关键海区SSTa的时滞关系比副高原始序列更为显著,相关持续时间更长;其中西伸脊点对ENSO响应要早于副高强度,分别在滞后3~5个月和5~6个月时相关系数达到最大.(3)在一次完整的副高TBO循环过程中,冬季赤道中东太平洋的类似El Ni o型总是和弱东亚冬季风耦合出现,对应副高TBO处于显著增强期;而冬季的类似La Ni a型则总是和强东亚冬季风耦合出现,副高TBO则处于显著减弱期.(4)在副高TBO循环中,热带海洋和大气环流呈现不对称的异常分布,副高TBO振荡在中东太平洋地区类似El Ni o型发展期较类似La Ni a型发展期更为显著,因此当热带海洋处于类似El Ni o型发展时,在短期气候预测中需要更加关注TBO年际分量的信号.
There is a significant quasi-biennial oscillation (TBO) period on the interannual scale in the East Asian monsoon region, which has an important impact on the climate anomalies in our country.Based on a set of reconstruction index that can objectively describe the western Pacific subtropical high pressure system, this paper mainly analyzes the East Asian Monsoon System (1) The TBO as an important year of the subtropical high, which is one of the key members in the western Pacific subtropical high (hereinafter referred to as the subtropical high) and its relationship with the SST anomaly in low latitudes In the late 1970s, the intergranular component showed a remarkable turning feature. The variation of TBO in the subtropical high over the past 30 years was significantly larger than that in the previous 30 years, and the decadal TBO was decadal in scale. (2) The time-lag relationship of SSTa in the sea area is more significant than that in the subtropical high sequence, and the duration of the correlation is longer. The response of the western extension ridge to ENSO is earlier than that of the subtropical high, with hysteresis of 3 to 5 months and 5 to 6 months (3) During a complete subtropical high TBO cycle, the similar El Ni o-type in the eastern equatorial Pacific in the winter equates with the weak East Asian winter monsoon, and the corresponding subtropical high TBO is significantly enhanced; and Similar to La Ni a in winter It is always coupled with the strong East Asian winter monsoon and the subtropical high TBO is significantly weakened. (4) In the subtropical high TBO cycle, the tropical oceans and the atmospheric circulation show an anomalous distribution, and the subtropical high TBO oscillation oscillates in the Middle East and Pacific region Similar El Ni o-type development is more pronounced than La Ni a-type development, so when the tropical oceans are in a similar El Ni o-type development, more attention needs to be paid to the interannual component of TBO signals in short-term climate predictions.