摘要
A rainstorm which occurred between May 22and 23, 2014 in Guangdong Province of the South Chinawarm region was simulated by using the ARW-WRFmodel. Three ＂echo-trainings＂ over the rainstorm centerwere analyzed and the results of both the simulation andobservational analysis showed that this rainstorm processwas composed of three stages. In the first stage, gravitywaves triggered the simultaneous but relatively indepen-dent formation of linearwhich moved toward theconvection and convective cells,northeast through the rain center,thus creating the echo-training. In the second stage, withthe formation of cold outflow, new convective cells werecontinuously created in the southwest and northwest of therain area and then gradually moved to merge into thenortheast rain area, thus forming a new echo-training. Inthe third stage, multiple rain bands above the rain areamoved southeastward and passed through the strongestprecipitation center, thus creating the third echo-training.The model simulation showed that a substantial warmingappeared at 900 hPa before the convective initiation,leading to the formation of a stable layer below 900 hPa,which was the primary cause for the gravity waves thattriggered the multiple convective cells. The multipleconvective cells formed the convective line, followingwhich new convection was formed from the cold outflowin its southwest and northwest directions. The newconvection in the southwest maintained the rain band;however, the new convection in the northwest, combinedwith the rain band of the north, formed a large radarreflectivity area and consequently, a larger MCS.
A rainstorm which occurred between May 22and 23, 2014 in Guangdong Province of the South Chinawarm region was simulated by using the ARW-WRFmodel. Three ＂echo-trainings＂ over the rainstorm centerwere analyzed and the results of both the simulation andobservational analysis showed that this rainstorm processwas composed of three stages. In the first stage, gravitywaves triggered the simultaneous but relatively indepen-dent formation of linearwhich moved toward theconvection and convective cells,northeast through the rain center,thus creating the echo-training. In the second stage, withthe formation of cold outflow, new convective cells werecontinuously created in the southwest and northwest of therain area and then gradually moved to merge into thenortheast rain area, thus forming a new echo-training. Inthe third stage, multiple rain bands above the rain areamoved southeastward and passed through the strongestprecipitation center, thus creating the third echo-training.The model simulation showed that a substantial warmingappeared at 900 hPa before the convective initiation,leading to the formation of a stable layer below 900 hPa,which was the primary cause for the gravity waves thattriggered the multiple convective cells. The multipleconvective cells formed the convective line, followingwhich new convection was formed from the cold outflowin its southwest and northwest directions. The newconvection in the southwest maintained the rain band;however, the new convection in the northwest, combinedwith the rain band of the north, formed a large radarreflectivity area and consequently, a larger MCS.
