Cloud and Precipitation Properties of MCSs Along the Meiyu Frontal Zone in Central and Southern China and Their Associated Large-Scale Environments
Cloud and Precipitation Properties of MCSs Along the Meiyu Frontal Zone in Central and Southern China and Their Associated Large-Scale Environments
复制标题
中国中南部梅雨锋一带MCSs的云和降水特征及其相关大尺度环境
DOI：
10.1029/2019jd031601
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发表时间：
2020-03-27
影响因子：
4.4
通讯作者：
Liu, Min
中科院分区：
文献类型：
--
作者：
Cui, Wenjun;Dong, Xiquan;Liu, Min
这项研究重点是研究MEIYU中尺度对流系统（MCSS）的云和降水特征及其与2014 - 2018年期间的卫星观测和重新分析数据的关系。分别检查了来自两个不同位置的MCS，即长江河流域（YRB）和中国南部（SC）。 MEIYU MCS的平均降水速率为3.6 mm/hr，在MEIYU期间占总降水的20％至60％。 MEIYU MCSS的昼夜周期在早晨显示最大降水量，这与夜间夜间低级射流（LLJ）过夜有关。尽管在MCS启动位置进行标准化时，发现YRB和SC中的天气设置相似，但MCSS在云最高高度，降水速率和持续时间方面表现出一些差异，这可能是由于局部强迫的差异。在MCSS的数量，云大小，寿命和降雨强度中发现了较大的年际变化，发现与大规模环境中的年际变化相关。通过将大规模环境与气候平均状态进行比较，我们发现研究期间具有最激烈的MCS活动的一年的特征是增强的西南LLJ，这增加了从印度洋的水分传输和增强的中间环层层。西风喷气机，它沿着梅尤沿线引起绝热升高，从而为对流创造了更有利的条件。
This study focuses on investigating the cloud and precipitation features of Meiyu mesoscale convective systems (MCSs) and their relation to the large-scale environments in central and southern China using satellite observations and reanalysis data during the period 2014-2018. MCSs from two different locations, the Yangtze River Basin (YRB) and Southern China (SC), are examined separately. The Meiyu MCSs have a mean precipitation rate of 3.6 mm/hr and contribute 20% to 60% of the total precipitation during the Meiyu period. The diurnal cycle of Meiyu MCSs shows a maximum precipitation amount in the morning, which is associated with the enhanced nocturnal low-level jet (LLJ) overnight. Although the synoptic setups in YRB and SC are found to be similar when normalized around the MCS initiation locations, MCSs exhibit some differences in terms of the cloud top height, precipitation rate, and duration, which are likely by the differences in the local forcing. Large interannual variations are found in MCSs' number, cloud size, lifetime, and rainfall intensity, which is found to be associated with the interannual variabilities in the large-scale environments. By comparing the large-scale environments with climatological mean states, we find that the year with the most intense MCS activity during the study period is characterized by an intensified southwesterly LLJ, which increases the moisture transport from the Indian Ocean and an enhancement of the midtropospheric westerly jet, which induces adiabatic ascent along the Meiyu front, creating more favorable conditions for convection.