Drivers of past and predicted changes of rainfall in and around Mainland Southeast Asia
Drivers of past and predicted changes of rainfall in and around Mainland Southeast Asia
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DOI：
10.21203/rs.3.rs-194416/v1
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发表时间：
2021-02
期刊：
影响因子：
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通讯作者：
N. Skliris;R. Marsh;I. Haigh;Melissa Wood;J. Hirschi;S. Darby;N. P. Quynh;N. Hung
中科院分区：
文献类型：
--
作者：
N. Skliris;R. Marsh;I. Haigh;Melissa Wood;J. Hirschi;S. Darby;N. P. Quynh;N. Hung
自20世纪50年代以来，观测雨量计/卫星和再分析数据集的平均和极端降雨在东南亚大陆（MSEA）的趋势进行了评估。雨量计资料显示，自1979年以来，越南和半岛西北部的年平均降水量和各种极端降水指数都有超过50%的强劲增长。在捕获大陆降水的长期趋势方面，再分析产品之间的高度不确定性是显而易见的。邻近海域的蒸发量增加--特别是阿拉伯海、孟加拉湾和中国南海--可能部分解释了过去40年来MSEA大部分地区降水量增加的原因。厄尔尼诺/南方涛动的遥远影响也可以部分解释最近几十年来由于拉尼娜现象占主导地位而出现的降水趋向于更强烈的区域水文循环的现象。MSEA降水的增加也与东南亚季风强度的增加以及1979-2018年季风活动中心向MSEA的北移有关。通过对CMIP 5耦合气候模式的历史模拟和RCP4.5/8.5世纪情景模拟的分析，进一步研究了区域水文循环的长期放大作用。CMIP 5集合平均值显示出强大的广泛的趋势，在湿季降水的MSEA在RCP的情况下，与所有主要的海洋水分来源的蒸发强烈增加。结果清楚地表明，随着极端降水事件频率和强度的增加，区域水循环加剧。
Observational rain gauge/satellite and reanalysis datasets since the 1950s are evaluated for trends in mean and extreme rainfall over Mainland Southeast Asia (MSEA). Rain gauge data indicate strong increases exceeding 50% in both annual mean precipitation and various extreme precipitation indices over Vietnam and the northwestern part of the peninsula since 1979. A high degree of uncertainty is evident between reanalysis products in capturing long-term trends in continental precipitation. Evaporation increases over adjacent seas - the Arabian Sea, the Bay of Bengal, and the South China Sea in particular- may partially explain increasing precipitation in large parts of MSEA over the last 40 years. The remote influence of ENSO may also partially explain the recent precipitation trend towards a more intense regional hydrological cycle, in response to predominant La Niña states over recent decades. Increasing precipitation in MSEA is also associated with increased monsoon intensity in southeast Asia and a northward shift of the monsoon activity centre towards MSEA over 1979–2018. Long-term amplification of the regional hydrological cycle is further investigated, through analysis of CMIP5 coupled climate models in historical and RCP4.5/8.5 21st century scenario simulations. The CMIP5 ensemble mean shows robust wide-spread trends in wet season precipitation over the MSEA in both RCP scenarios linked with strong increases in evaporation in all major oceanic moisture sources. Results clearly demonstrate an intensification of the regional water cycle with increasing frequency and intensity of extreme precipitation events.