摘要
Statistical studies were conducted on the southwest vortex(SWV) during the summers of 2000–13 using high-resolution reanalysis data with a horizontal resolution of 0.5°× 0.5°. A total of 578 SWVs were detected, with a maximum interannual frequency of 55. The variation of the interannual frequency featured a period of around six years. The most active period of SWVs was early July and the maximum occurrence of SWVs appeared in early morning(0200–0800 Beijing Standard Time(BST)). Most of the SWVs were short-lived, with only 66 cases(11.4%) lasting for more than 24 h. In addition, the moving tracks and three-dimensional shape of long-lived(≥ 36 h) SWVs are also presented. For those SWVs that lasted for more than 12 h, four types of SWVs(Types I–IV) were identified using a new method, and the results indicated that the dynamical and thermodynamical conditions before the formation of SWVs are effective indicators of the subsequent evolution of the vortex and associated severe weathers. Moreover, a further level of classification was also constructed for Type II SWVs, which accounted for the largest proportion out of Types I–IV, and the results indicated that the lifespan, radius and maximum 6-h precipitation were all closely related to the intensity of precipitation before the formation of SWVs.
Statistical studies were conducted on the southwest vortex（SWV） during the summers of 2000–13 using high-resolution reanalysis data with a horizontal resolution of 0.5°× 0.5°. A total of 578 SWVs were detected, with a maximum interannual frequency of 55. The variation of the interannual frequency featured a period of around six years. The most active period of SWVs was early July and the maximum occurrence of SWVs appeared in early morning（0200–0800 Beijing Standard Time（BST））. Most of the SWVs were short-lived, with only 66 cases（11.4%） lasting for more than 24 h. In addition, the moving tracks and three-dimensional shape of long-lived（≥ 36 h） SWVs are also presented. For those SWVs that lasted for more than 12 h, four types of SWVs（Types I–IV） were identified using a new method, and the results indicated that the dynamical and thermodynamical conditions before the formation of SWVs are effective indicators of the subsequent evolution of the vortex and associated severe weathers. Moreover, a further level of classification was also constructed for Type II SWVs, which accounted for the largest proportion out of Types I–IV, and the results indicated that the lifespan, radius and maximum 6-h precipitation were all closely related to the intensity of precipitation before the formation of SWVs.
基金
supported by a project of the Chengdu Institute of Plateau Meteorology, CMA (Grant No. LPM2011006)
the State Grid Science & Technology Project (GC71-13-007)
the National Natural Science Foundation of China (Grant Nos. 41205027, 41375053, and 41375058)
