Cloud and Precipitation Properties of MCSs Along the Meiyu Frontal Zone in Central and Southern China and Their Associated Large‐Scale Environments. Issue 6 (18th March 2020)

• Record Type: Journal Article
• Authors: Cui, Wenjun; Dong, Xiquan; Xi, Baike; Liu, Min
• Is Part Of: Journal of geophysical research. Volume 125:Issue 6(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-03-18
• Subjects: Meiyu rainfall -- MCS precipitation -- extreme precipitation; Atmospheric physics -- Periodicals; Geophysics -- Periodicals; 551.5
• DOI: 10.1029/2019JD031601
• Languages: English
• ISSNs: 2169-897X

Abstract

Abstract: 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. Key Points: MCSs initiation environments are similar in southern and central China, but MCSs' cloud and precipitation properties are different Cloud and precipitation features of Meiyu MCSs have large interannual variation due to the variations in large‐scale environments The strength of MCS activity is related to moisture availability, and the strength of LLJ, midtropospheric westerly jet, and local forcing