Abstract
To have a clear understanding of the convective precipitation over the Tibetan Plateau (TP) and its surrounding regions, this research systematically studied characteristics of distribution of convective storm top altitudes over the Tibetan Plateau and its surrounding regions by using the level-2 orbital data obtained by the Global Precipitation Mission (GPM) Dual-frequency Precipitation Radar (DPR). The following conclusions are drawn in this study. (1) Because of the development of Asia summer monsoon, the number of samples of precipitation with storm top altitude above 10 km increases gradually from June to August, and all the samples of precipitation diminishes with the increases of altitude. That is, the higher the storm top altitude, the less the frequency of precipitation. (2) The deep convection frequency above 10 km altitude over the Tibetan Plateau and its surrounding regions is less than 0.8%. The deep convection frequency above 14 km is obviously less than the 10 km deep convection, not exceeding 0.2%. (3) With the increase of convective storm top altitude, the proportion of corresponding deep convection decreases exponentially. The contribution of convective precipitation to total precipitation is consistent with the contribution of convective precipitation frequency to total precipitation frequency, and the both area fractions of them decrease rapidly with the increases of the contribution. Besides, both of the two maximum contributions are below 40%. (4) The storm top altitude and surface rain rate of convective precipitation are the lowest in June and the highest in August. Furthermore, the storm top altitude over the TP rises slowly from the western part of the plateau to the eastern part, and the rain rate shows a significant gradient change with the increases of height. Below 6 km altitude, the maximum value of rain rate can reach 8 mm/h, but the precipitation intensity reduce to 4 mm/h when the altitude is above 6 km.
Highlights
The altitude of the storm top is known as the maximum height of the precipitation cloud top detected by the precipitation radar in the precipitation cloud, which is related to the strength of the updraft and atmospheric stability [1]
The samples consist of convective precipitation, stratiform precipitation and other types of precipitation
In order to understand the distribution of precipitation over the Tibetan Plateau and its surrounding regions, especially the convective precipitation, the frequency of precipitation is used to show the distribution of convective precipitation
Summary
The altitude of the storm top is known as the maximum height of the precipitation cloud top detected by the precipitation radar in the precipitation cloud, which is related to the strength of the updraft and atmospheric stability [1]. The situation has changed since 1979, mainly due to the First and Second Plateau Meteorological Science Experiments (1979 and 1998), respectively, and the observations by the first satellite-borne precipitation radar (PR) on board the Tropical Rainfall Measuring Mission (TRMM), which was launched in 1997. These satellite observation data provide a convenient way to research the plateau precipitation characteristics and convective activities [11,12,13,14]. The characteristics of convective precipitation over the Tibetan Plateau and its surrounding areas in summer (June to August) were analyzed by using the GPM DPR_HS data from 2014 to 2016
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