Based on the data of the National Climate Center of China and the NCEP of the United States, a heavy precipitation process in eastern China during July 26-29, 2022 was analyzed. The results show that: The precipitatio...Based on the data of the National Climate Center of China and the NCEP of the United States, a heavy precipitation process in eastern China during July 26-29, 2022 was analyzed. The results show that: The precipitation process was formed under the influence of the low level southwest jet stream at the edge of the subtropical high. The eastward development of the low vortex and trough and the continuous strengthening of the upper level jet stream, combined with the influence of topographic convergence, provided extremely favorable conditions for the occurrence of the rainstorm.展开更多
Observational analysis shows that a Mesoscale Convective System (MCS) occurred on May 13-14 2004 along the coastal area in South China. The MCS initiated among the southwesterly flows within a west-east orientation lo...Observational analysis shows that a Mesoscale Convective System (MCS) occurred on May 13-14 2004 along the coastal area in South China. The MCS initiated among the southwesterly flows within a west-east orientation low-level shear line. Associated with the system, in its subsequent development stages, no distinct vortex circulation developed in low-level. Instead, a cyclonic flow disturbance was observed in the mid-troposphere. How the convection starts to develop and evolve into a MCS With observational analysis and numerical simulation, the problem has been studied. The high-resolution MM5 simulation shows that topographic convergence along the coastal line and the nearby mountains in western South China plays an important role to initiate the MCS convection. Once the convection occurs, due to the condensation heating, a cooperative interaction between the preexisting mid-level disturbance and convection is created, which may greatly affect the MCS development during periods when the system continues moving eastward. Compared to some typical MCS that happen in Southern China, which are usually accompanied with upward development of cyclonic vorticity, the development and evolution of the investigated MCS shows distinguishing features. In this article, the physical mechanisms responsible for the intensification of mid-level disturbance are discussed, and a viewpoint to interpret the effects of mid-level disturbance on the MCS organizational development is proposed.展开更多
文摘Based on the data of the National Climate Center of China and the NCEP of the United States, a heavy precipitation process in eastern China during July 26-29, 2022 was analyzed. The results show that: The precipitation process was formed under the influence of the low level southwest jet stream at the edge of the subtropical high. The eastward development of the low vortex and trough and the continuous strengthening of the upper level jet stream, combined with the influence of topographic convergence, provided extremely favorable conditions for the occurrence of the rainstorm.
基金Fundamental Scientific Research Condition, a project of Ministry of Science & Technology(2003DIB4J145)Key Scientific Project for Guangdong Province (2004B32601002)
文摘Observational analysis shows that a Mesoscale Convective System (MCS) occurred on May 13-14 2004 along the coastal area in South China. The MCS initiated among the southwesterly flows within a west-east orientation low-level shear line. Associated with the system, in its subsequent development stages, no distinct vortex circulation developed in low-level. Instead, a cyclonic flow disturbance was observed in the mid-troposphere. How the convection starts to develop and evolve into a MCS With observational analysis and numerical simulation, the problem has been studied. The high-resolution MM5 simulation shows that topographic convergence along the coastal line and the nearby mountains in western South China plays an important role to initiate the MCS convection. Once the convection occurs, due to the condensation heating, a cooperative interaction between the preexisting mid-level disturbance and convection is created, which may greatly affect the MCS development during periods when the system continues moving eastward. Compared to some typical MCS that happen in Southern China, which are usually accompanied with upward development of cyclonic vorticity, the development and evolution of the investigated MCS shows distinguishing features. In this article, the physical mechanisms responsible for the intensification of mid-level disturbance are discussed, and a viewpoint to interpret the effects of mid-level disturbance on the MCS organizational development is proposed.
