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本文采用了p-σ五层原始方程模式模拟并研究了赤道西太平洋-印度洋海温距平场对亚洲夏季风的影响,计算了四种不同的海温距平试验方案。试验结果表明赤道西太平洋海温正距平使对流层下层的印度低压明显加强,副高北挺,季风槽加深,同时加强了对流层上层的反气旋环流。赤道西印度洋暖海温的模拟结果与赤道西太平洋暖海温对上述系统的影响相反,而赤道西印度洋冷海温对季风环流的影响与赤道西太平洋暧海温的影响一致。试验进一步表明赤道西太平洋-印度洋海温距平的纬向梯度方向对亚洲夏季风的影响是主要的,这一结论与实际观测结果一致。本文进一步讨论了赤道海温距平对越赤道气流、印度洋赤道东-西纬向环流和非绝热加热场的影响,结果都表明赤道西太平洋海温正距平和赤道西印度洋海温负距平的模拟特征与反El Nino年亚洲夏季环流特征类似,而赤道西印度洋海员正距平的模拟特征与El Nino年亚洲夏季坏流特征类似。
In this paper, the p-σ five-layer original equation model was used to simulate and study the influence of the equatorial Pacific-Indian Ocean SST anaplastic summer monsoon on the Asian summer monsoon. Four different SST anomalies were calculated. The results show that positive anomalies in the western equatorial Pacific mean that the Indian low pressure in the lower troposphere is significantly strengthened. The subtropical North Bend and the monsoon trough deepen, and the anticyclone circulation in the upper troposphere is strengthened. The simulation results of the warm Indian Ocean temperature in the western Indian Ocean of the equatorial Pacific are opposite to those of the western equatorial Pacific warm SST, while the effects of the cold SST on the monsoon circulation in the western equatorial Pacific are consistent with those of the western equatorial Pacific. The experiment further shows that the influence of the zonal gradient of the equatorial Pacific-Indian Ocean SST on the Asian summer monsoon is dominant. This conclusion is consistent with the actual observations. This paper further discusses the influence of the equatorial SST anomalies on the cross-equatorial flow, the equatorial east-west latitudinal circulation and the adiabatic heating field in the equatorial Pacific. The results show that the positive SST anomalies over the western equatorial Pacific and the negative SST anomalies over the western Indian Ocean The simulation features are similar to those of the reverse El Nino summer monsoon circulation in Asia, while the positive anomalies of sea-level seamen in the western equatorial Indian Ocean are similar to those of the El Nino summer monsoon.