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Key statistical characteristics of the mesoscale convective systems generated over the Tibetan Plateau and their relationship to precipitation and southwest vortices
Author(s) -
Mai Zi,
Fu ShenMing,
Sun JianHua,
Hu Liang,
Wang Xiuming
Publication year - 2021
Publication title -
international journal of climatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.58
H-Index - 166
eISSN - 1097-0088
pISSN - 0899-8418
DOI - 10.1002/joc.6735
Subject(s) - mesoscale meteorology , vorticity , geostationary orbit , plateau (mathematics) , precipitation , convection , mesoscale convective system , vortex , environmental science , climatology , satellite , meteorology , atmospheric sciences , geology , physics , mathematics , mathematical analysis , astronomy
Based on hourly geostationary satellite temperature‐of‐black‐body data, 9,754 mesoscale convective systems (MCSs) are found to form over the Tibetan Plateau (TP) during 16 warm seasons. In the whole study period, neither the occurrence numbers of these MCSs nor their other key characteristics are found to have a significant trend of increasing/decreasing. The MCSs can form anywhere over the TP, and ~6.6% of them can move eastward and vacate the TP (defined as the eastward‐moving type [EMT]). The EMTs' mean occurrence frequency and lifespan are ~0.3 per day and ~12.0 hr, respectively. Compared to the MCSs that do not vacate the TP, the EMTs usually have stronger intensity, longer lifespan, and develop more rapidly but generate in a drier environment. The vacating stage of an EMT usually begins in the latter half of its lifespan, and an EMT tends to reach its maximum cloud area when it is about to vacate the TP. After vacating the TP, an EMT usually weakens at first and then enhances again. Vorticity budget indicates that the convergence‐related horizontal shrinking and the convection‐related vertical vorticity transport govern the cyclonic‐vorticity increase/maintenance associated with the longer‐lived EMTs. Of all the EMTs, only ~8% are associated with southwest vortices (SWVs), and the precipitation related to these EMTs contributes ~20% to the local hourly heavy precipitation. Compared to the EMTs that are not related to SWVs, those that are generally vacate the TP sooner, last longer having vacated the TP, and have longer whole lifespans.