The Variation of the Intensity, Height, and Size of Precipitation Systems with El Niño–Southern Oscillation in the Tropics and Subtropics
The Variation of the Intensity, Height, and Size of Precipitation Systems with El Niño–Southern Oscillation in the Tropics and Subtropics
复制标题
热带、亚热带降水系统强度、高度和规模随厄尔尼诺-南方涛动的变化
作者：
Nana Liu;Chuntao Liu;T. Lavigne
利用1998-2013年16 a（1998-2013）的热带降水测量使命（TRMM）降水特征（PF）数据库，研究了厄尔尼诺-南方涛动（ENSO）对热带和副热带降水系统特征的影响。深层系统组分的显著差异（20分贝雷达回波顶大于10公里）和中尺度对流系统（MCS）ENSO不同阶段之间的区域（面积大于2000 km 2）出现在特定区域，包括中太平洋（CPACI）、西海洋大陆（WMC）、东海洋大陆（EMC）、墨西哥湾（GM）、阿根廷（阿尔根）、澳大利亚（AUS）。分析了季节性的多变量ENSO指数（MEI）和深对流和MCS的人口比例之间的决定系数R2在这些地区。这些降水系统对ENSO的响应在冬半年比夏半年明显。在厄尔尼诺期间的CPACI，GM，和阿尔根的降雨量增加被发现与更多的降水事件和更高的分数的强烈，深，大降水系统。在厄尔尼诺现象期间，澳大利亚的降水事件较少，浅层和小型降水系统的比例较高。EMC和WMC在拉尼娜期间的MCS比例高于厄尔尼诺条件。在拉尼娜现象期间，EMC观测到更高比例的深对流。然而，在厄尔尼诺条件下，WMC有更高比例的深对流，可能与印度洋偶极子的影响有关。
A 16-yr (1998–2013) Tropical Rainfall Measuring Mission (TRMM) Precipitation Feature (PF) database is used to examine the impacts of El Niño–Southern Oscillation (ENSO) on the characteristics of precipitation systems in the tropics and subtropics. Noticeable differences in the fractions of deep systems (20-dBZ radar echo tops greater than 10 km) and mesoscale convective systems (MCSs) (an area greater than 2000 km2) between different phases of ENSO are found over specific regions, including the central Pacific (CPACI), the western Maritime Continent (WMC), the eastern Maritime Continent (EMC), Gulf of Mexico (GM), Argentina (ARGEN), and Australia (AUS). The coefficients of determination R2 between the multivariate ENSO index (MEI) and the population fractions of deep convection and MCSs are analyzed seasonally over these regions. The responses from these precipitation systems to ENSO are found to be more pronounced in the winter half-year than in the summer half-year. An increase of rainfall during El Niño periods over the CPACI, GM, and ARGEN is found to be associated with more precipitation events and a higher fraction of intense, deep, and large precipitation systems. AUS has fewer precipitation events and a higher fraction of shallow and small precipitation systems during El Niño conditions. Both EMC and WMC have a higher fraction of MCSs during La Niña than El Niño conditions. The EMC observes a higher fraction of deep convection during La Niña conditions. However, the WMC has a higher fraction of deep convection during El Niño conditions, possibly related to the effect of the Indian Ocean dipole.