Large‐scale dynamic, heat and moisture structures of monsoon‐influenced precipitation in the East Asian monsoon rainy area
Large‐scale dynamic, heat and moisture structures of monsoon‐influenced precipitation in the East Asian monsoon rainy area
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DOI：
10.1002/qj.3956
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发表时间：
2020-12
影响因子：
8.9
通讯作者：
Chunyan Zhang;Donghai Wang;Zihao Pang;Yu Zhang;Xiaoling Jiang;Zhilin Zeng;Zhenzhen Wu
中科院分区：
文献类型：
--
作者：
Chunyan Zhang;Donghai Wang;Zihao Pang;Yu Zhang;Xiaoling Jiang;Zhilin Zeng;Zhenzhen Wu
本研究探讨大尺度动力结构沿着与季风影响的降水在东亚季风区的一个典型的多雨域的热量和水分收支。基于多个测量数据的大尺度动力学和动力学一致的强迫数据由一维约束变分分析方法产生。利用强迫数据，记录了南海季风爆发（SCSMO）前显着季风前降雨、SCSMO期间极端降雨和SCSMO后持续强降雨的大尺度状态的明显特征。季风前期主要是由弱云和离散云造成的。强降水期与强深对流系统西移有关，持续降水期与南海北方强对流系统分离出的中等对流单体有关。包括垂直速度、风辐合和非绝热加热和干燥在内的大尺度特征在极端降雨（前季风）期间最强（最弱）。在季风前期和持续降雨期，垂直速度和非绝热加热和干燥的周期平均廓线呈单峰结构。然而，在极端降雨期间，这些大尺度状态的垂直结构和强度出现了跳跃式突变。暴雨期间垂直速度和非绝热加热垂直廓线上的多个峰值可能表明多种对流云系共存。极端降水的非绝热加热廓线表明，第一个降水峰与层状砧和对流云的相继出现有关，而强度最大的第二个降水峰则与浅层对流云、强深对流云和退流层状砧有关。
This study investigated large‐scale dynamic structures along with heat and moisture budgets associated with monsoon‐influenced precipitation over a typical rainy domain in the East Asian monsoon region. Large‐scale dynamically and thermodynamically consistent forcing data based on multiple measurements were produced by a one‐dimensional constrained variational analysis method. Using the forcing data, distinct characteristics of large‐scale states were documented for cases of notable pre‐monsoon rainfall before the South China Sea monsoon onset (SCSMO), extreme rainfall during SCSMO, and persistent strong rainfall after SCSMO. The pre‐monsoon period mainly resulted from weak and discrete cloud regimes. The extreme‐rain period was associated with a severe deep convective system moving from the west, and the persistent‐rain period was related to moderate convective cells separated from the strong convective system over the northern South China Sea. Large‐scale features including vertical velocity, wind convergence, and diabatic heating and drying were the strongest (weakest) during the extreme‐rain (pre‐monsoon) period. For the pre‐monsoon and persistent‐rain periods, the period‐averaged profiles of vertical velocity and diabatic heating and drying showed a one‐peak structure. However, during the extreme‐rain period, a leap‐forward mutation was seen in the vertical structure and magnitude of these large‐scale states. The multiple peaks shown in the vertical profiles of vertical velocity and diabatic heating during the extreme‐rain period may indicate various convective cloud systems co‐existed. The diabatic heating profiles of extreme rainfall indicated that the first rainfall peak was related to the successive occurrence of stratiform anvils and convective clouds, while the second rainfall peak, which was most intense, was associated with shallow convective clouds, severe deep convective clouds, and detraining stratiform anvils.