image: Figure1 Schematic illustration of the eastward propagating MCS view more
Credit: ©Science China Press
The Tibetan Plateau (TP) which is known as “the third pole of the world” is a huge heat source in summer. Mesoscale convective systems (MCSs) are active over the TP, which can vacate the plateau under favorable environmental conditions. After vacating, the MCSs can induce a series of heavy rainfall events, resulting in severe flooding. Recently, a research has shown the universal features of the long-lived eastward propagating MCSs over the TP. This has made up for the shortcomings of the existing case studies on these MCSs.
The related paper is entitled “A semi-idealized modeling study on the long-lived eastward propagating mesoscale convective system over the Tibetan Plateau”. It is recently published in Science China Earth Sciences in 2021. The corresponding author is Prof. Shenming Fu from the Institute of Atmospheric Physics, Chinese Academy of Sciences. This study investigated a type of long-lived eastward propagating MCSs based on semi-idealized simulations and dynamical diagnoses, which showed the universal features and mechanisms of these MCS for the first time.
A large number of observations and studies have confirmed that the MCSs moving out from the Tibetan Plateau is an important factor for rainstorms east of the plateau. Numerous predecessors have paid attention to this phenomenon and carried out a series of studies. However, the relevant studies are based on individual cases, and the conclusions are significantly different, which can not reveal the universal characteristics of such phenomena. Mastering the universal features is the key to deepen the understanding of such systems, and it is also very important to improve the accuracy of relevant predictions.
In this study, semi-idealized simulations and dynamic diagnoses were carried out on long-lived eastward propagating MCSs of the same type during 16 warm seasons. This shows the universal characteristics and mechanisms of this type of MCSs for the first time. It is found that the coupling and decoupling with the plateau vortex is very important for the evolution of the eastward propagating MCSs; after vacating, the MCSs tend to weaken, and the coupling with the shortwave trough in the eastern section of the plateau is the key to their rapid redevelopment; on the one hand, eastward propagating MCSs affect the eastern part of the Tibetan Plateau and some downstream areas by directly producing precipitation, and on the other hand, it indirectly affects the precipitation in a wider range of downstream areas by regulating the large-scale environmental circulation over and around the Tibetan Plateau.
This result enriches the study of rainstorms in the Tibetan Plateau and the Yangtze-Huai River Basin in China. It is not only of great significance to the theoretical study of MCSs over the Tibetan Plateau, but also of great reference value to improve the prediction accuracy of rainstorms that are caused by eastward propagating MCSs.
This research was funded by the National Key R&D Program of China (Grant No. 2018YFC1507606), the National Natural Science Foundation of China (Grant Nos. 41775046, 42075002, 91637211, and 42030611), the Foundation of Heavy Rain and Drought-Flood Disasters in Plateau and Basin Key Laboratory of Sichuan Province (Grant No. SZKT202001), and the Youth Innovation Promotion Association, Chinese Academy of Sciences.
See the article:
Fu S, Mai Z, Sun J, Li W, Zhong Q, Sun J, Zhang Y. 2021. A semi-idealized modeling study on the long-lived eastward propagating mesoscale convective system over the Tibetan Plateau. Science China Earth Sciences, 64(11): 1996–2014, https://doi.org/10.1007/s11430-020-9772-1
https://www.sciengine.com/publisher/scp/journal/SCES/doi/10.1007/s11430-020-9772-1?slug=fulltext
Journal
Science China Earth Sciences