ENSO非对称性对热带降水的影响研究

利用1966—2015年多种海气资料,分析了热带太平洋海域的ENSO非对称性表现,结果表明:在赤道东太平洋,ENSO暖事件强度大于ENSO冷事件,而在赤道中、西太平洋上与之相反,即在振幅强度和发生位置上存在不对称。研究还发现,在厄尔尼诺年的冬季,热带印度洋-太平洋海域整体上呈现出"正-负-正"的降水异常分布形势,而在拉尼娜年冬季,则呈现出"负-正-负-正"的降水异常分布形势,并且,降水距平的正负异常中心在厄尔尼诺年与拉尼娜年冬季存在纬向不同程度的偏移,表现出ENSO冷暖事件年冬季降水异常的非对称性。通过定量计算降水对热带海域的贡献,得到赤道中太平洋的降水量主要来源于厄尔尼诺年,赤道东太平洋的降水则主要来源于拉尼娜年,而热带印度洋及赤道西太平洋的大部分降水由中性年贡献。此外,对热带印度洋-太平洋划分厄尔尼诺强度与热带降水线性与非线性区域,发现在赤道西太平洋和赤道中太平洋及其偏东区域线性关系较为明显。

The influence of ENSO asymmetry on tropical precipitation

Multiple sets of marine meteorological data from 1966 to 2015 are used to analyze the characteristics of ENSO asymmetry in tropical Pacific Ocean.It is shown that the intensity of ENSO warm event is greater than that of ENSO cold event in the eastern equatorial Pacific Ocean.,whereas it is opposite in the equatorial mid and western Pacific Ocean with asymmetry in amplitude intensity and position.Furthermore,the precipitation anomaly shows a"positive-negative-positive"pattern in the tropical Indian-Pacific Ocean during the winter of El Ni?o event,while it shows a"negative-positive-negative-positive"pattern during the winter of La Ni?a event.The positive and negative center of precipitation anomaly during the winter of El Ni?o event and La Ni?a event reveals meridional deviation in various degree,which demonstrate the asymmetry of precipitation anomaly in the winter of ENSO cold and warm events.Quantitative calculation of the contribution of precipitation to the tropical ocean suggest that precipitation mainly is gained in El Nino years in the equatorial mid-Pacific Ocean and gained in La Ni?a years in the equatorial eastern Pacific Ocean,whereas it is largely gained in neutral years in the tropical Indian Ocean and the equatorial western Pacific Ocean.In addition,a significant linear relationship is found between the equatorial western Pacific Ocean and the equatorial mid-Pacific and its adjacent eastern areas by dividing the linear and non-linear areas of El Ni?o intensity and tropical precipitation in the tropical Indian-Pacific Ocean.