By using the conventional observation data, the FY-2E satellite Black Body Temperature (TBB) data, the 0.25°×0.25° data of European Center, and based on the chosen dynamical factors including mass divergence, vertical helicity, mass vertical helicity, moisture vertical helicity, divergence vertical flux, density divergence vertical flux and moisture divergence flux, diagnostic analysis was performed for a rainstorm process occurred in Sichuan Basin during 16-18 August 2015. The results showed that:(1) the rainstorm event was caused by the southwest vortex formed and maintained in the central Sichuan Basin. The southwest vortex was because of the eastward movement of plateau vortex and plateau shear lines toward Sichuan Basin. (2) Following the eastward movement and weakening of the plateau low-pressure systems (plateau vortex and plateau shear lines), and the producing and development of the southwest vortex, the convective cloud cluster went through the process of "reinforce-combine-weaken-regeneration-reinforce-weaken". (3) Dynamical factors had good indication significance for the development and evolution of the rainstorm. The high value area of the dynamical factors basically covered the strong precipitation area. At the beginning while southwest vortex formed, the distribution of the dynamical factors and the plateau shear line were the same, and the rainfall center which located at the high value area of the dynamical factors and the right side of the plateau shear line was the same as the center of the southwest vortex. At the strong stage of the southwest vortex, the high value area of the dynamical factors, the center of the southwest vortex and the rainfall center coincided. The precipitation area had profound positive vorticity column and upward movement, but the convergence layer was too shallow. The mass divergence convergence, vertical upward transportation and convergence upward movement of cyclonic vorticity and moisture flux vorticity appeared above the precipitation area. Due to the vorticity effect of the vortex-type influence system was more obvious than divergence effect, the vertical structure of three helicity-type dynamical factors including vertical helicity, mass vertical helicity and moisture vertical helicity was very significant from the lower layer to the upper layer.
[1]Gao S T, Ran L K, Li N, et al, 2013. The "Ensemble Dynamic Factors" approach to predict rainstorm[J]. Torrential Rain Disaster, 32(4):289-302.<br/>高守亭, 冉令坤, 李娜, 等, 2013.集合动力因子暴雨预报方法研究[J].暴雨灾害, 32(4):289-302.
[2]Li G P, 2013. Advances in Tibetan plateau vortex and southwest vortex research and related scientific problems[J]. Desert Oasis Meteor, 7(3):1-6.<br/>李国平, 2013.高原涡、西南涡研究的新进展及有关科学问题[J].沙漠与绿洲气象, 7(3):1-6.
[3]Li Q, Yang S, Cui X P, et a1, 2016. Diagnosis and forecasting of dynamical parameters for a heavy rainfall event in Sichuan Province[J]. Atmos Sci, 40(2):341-356.<br/>李琴, 杨帅, 崔晓鹏, 等, 2016.四川暴雨过程动力因子指示意义与预报意义研究[J].大气科学, 40(2):341-356.
[4]Lu P, Yu R C, Zhou T J, 2009. Numerical simulation on the sensitivicy of heavy rainfall over the western Sichuan Basin to initial water vapor condition[J]. Atmos Sci, 33(2):241-250.<br/>卢萍, 宇如聪, 周天军, 2009.四川盆地西部暴雨对初始水汽条件敏感性的模拟研究[J].大气科学, 33(2):241-250.
[5]Luo S W, 1992. Study on some kinds of weather systems over and around the Qinghai-Xizang Plateau[M]. Beijing:China Meteorological Press, 14-25.<br/>罗四维, 1992.青藏高原及其邻近地区几类天气系统的研究[M].北京:气象出版社, 14-25.
[6]Luo X P, Song W W, 2011. A comprehensive analysis of a rainstorm in Sichuan Basin in light of the interaction of two vortex[J]. Journal of Yunnan University (Natural Sciences), 33(5):554-562.<br/>罗喜平, 宋雯雯, 2011.两涡相互作用下四川盆地暴雨过程的综合分析[J].云南大学学报(自然科学版), 33(5):554-562.
[7]Ran L K, Chu Y L, 2009. Diagnosis of vertical helicity, divergence flux and their extensions in heavy-rainfall events[J]. Acta Physica Sinica, 58(11):8094-8l06.<br/>冉令坤, 楚艳丽, 2009.强降水过程中垂直螺旋度和散度通量及其拓展形式的诊断分析[J].物理学报, 58(11):8094-8106.
[8]Ran L K, Qi Y B, Hao S C, 2014. Analysis an d forecasting of heavy rainfall case on 21 July 2012 with dynamical parameters[J]. Atmos Sci, 38(1):83-100.<br/>冉令坤, 齐彦斌, 郝寿昌, 2014. "7·21"暴雨过程动力因子分析和预报研究[J].大气科学, 38(1):83-100.
[9]Shi R, He G B, Long K J, 2015. Analysis on a heavy vortex rainstorm in Sichuan Basin from 29 June to 2 July 2013[J]. J Arid Meteor, 33(5):845-855.<br/>师锐, 何光碧, 龙柯吉, 2015.一次四川盆地低涡型特大暴雨过程分析[J].干旱气象, 33(5):845-855.
[10]Song W W, Li G P, 2016. Analysis and application of the two type vorticity vectors on a heavy rainfall in Sichuan Basin[J]. Plateau Meteor, 35(6):1464-1475. DOI:10.7522/j.issn. 1000-0534.2015.00115.<br/>宋雯雯, 李国平, 2016.两类涡度矢量对四川盆地一次暴雨过程的分析应用[J].高原气象, 35(6):1464-1475.
[11]Wang Y P, Cui X P, Ran L K, et al, 2015. Diagnosis of dynamical parameters in torrential rain associated with typhoon "Bilis" in 2006[J]. Atmos Sci, 39(4):747-756.<br/>汪亚萍, 崔晓鹏, 冉令坤, 等, 2015.动力因子对2006"碧利斯"台风暴雨的斩断分析[J].大气科学, 39(4):747-756.
[12]Wang C X, Gao S T, Liang L, et a1, 2013. Diagnostic analysis of dynamical parameters for Sichuan rainstorm influenced by terrain[J]. Atmos Sci, 37(5):1099-1110.<br/>王成鑫, 高守亭, 梁莉, 等, 2013.动力因子对地形影响下的四川暴雨落区的诊断分析[J].大气科学, 37(5):1099-1110.
[13]Wang Y, He L F, Dai K, et al, 2017. An ensemble sensitivity analysis of a heavy rainfall over Sichuan Basin under interaction between plateau vortex and southwest vortex[J]. Plateau Meteor, 36(5):1245-1256. DOI:10.7522/j.issn. 1000-0534.2016.00102.<br/>王毅, 何立富, 代刊, 等, 2017.集合敏感性方法在高原涡和西南涡引发暴雨过程中的应用[J].高原气象, 36(5):1245-1256.
[14]Wu Z, Fan G Z, Zhou D W, et al, 2014. Numerical simulation of the rainstorm process in Ya'an based on WRF model[J]. Plateau Meteor, 33(5):1332-1340. DOI:10.7522/j.issn. 1000-0534.2013.00084.<br/>吴泽, 范广洲, 周定文, 等, 2014.基于WRF模式的雅安暴雨数值模拟研究[J].高原气象, 33(5):1332-1340.
[15]Xu W J, Zhang Y C, 2017. Numerical study on the feedback between latent heating and convection in a Qinghai-Tibetan plateau vortex[J]. Plateau Meteor, 36(3):763-775. DOI:10.7522/j.issn. 1000-0534.2016.00061.<br/>许威杰, 张耀存, 2017.凝结潜热加热与对流反馈对一次高原低涡过程影响的数值模拟[J].高原气象, 36(3):763-775.
[16]Yang S N, Zhang F H, Xu J, et al, 2016. Mesoscale convective systems and characteristics of environment field of a heavy rainfall process occurred in Sichuan Basin[J]. Plateau Meteor, 35(6):1476-1486. DOI:10.7522/j.issn. 1000-0534.2015.00105.<br/>杨舒楠, 张芳华, 徐珺, 等, 2016.四川盆地一次暴雨过程的中尺度对流及其环境场特征[J].高原气象, 35(6):1476-1486.
[17]Yu B, Lin Y H, 2008. A case study of southwest vortex causing heavy rainfall in eastern Sichuan Basin[J]. Atmos Sci, 32(1):141-154.<br/>于波, 林永辉, 2008.引发川东暴雨的西南低涡演变特征个例分析[J].大气科学, 32(1):141-154.
[18]Yu S H, 1984. Resultant analysis of large scale heavy rain storm over Sichuan Basin[J]. Plateau Meteor, 3(3):58-67.<br/>郁淑华, 1984.四川盆地大范围强暴雨过程的合成分析[J].高原气象, 3(3):58-67.
[19]Zhao Y C, Wang Y H, 2010. A case study on plateau vortex inducing southwest vortex and producing extremely heavy rain[J]. Plateau Meteor, 29(4):819-831.<br/>赵玉春, 王叶红, 2010.高原涡诱生西南涡特大暴雨成因的个例研究[J].高原气象, 29(4):819-831.
[20]Zhou G B, Cui X P, Gao S T, 2012. The high-resolution numerical simulation and diagnostic analysis of the landfall process of typhoon Fungwong[J]. Atmos Sci, 36(1):23-34.<br/>周冠博, 崔晓鹏, 高守亭, 2012.台风"凤凰"登陆过程的高分辨率数值模拟及其降水的诊断分析[J].大气科学, 36(1):23-34.
[21]Zhu G, 2012. The numerical study of the rainstorm occurred in Shandong Province in May 2009[D]. Nanjing: Nanjing University of Information Science & Technology.<br/>朱刚, 2012.2009年5月一次山东暴雨的数值模拟研究[D].南京: 南京信息工程大学.
