Gaoyuan qixiang (Dec 2023)
Radar Climatological Characteristics of Warm Season Convection in Southeast of Gansu
Abstract
The radar climatology characteristics of convection in southeastern Gansu Province during the warm season （June to August）were investigated using Tianshui Doppler radar data that filtered by “Maximum Method” and tracking statistics by “TITAN”（Thunderstorm identification Tracking Analysis and Nowcasting） algorithm.The frequency of convective activity showed large value in high altitude mountains with the Great value center located in windward slope of Western Liupanshan Mountain and undulating region of western Qinling Mountains， and the peak time in August.The convective storm mainly propagated from northwest to southeast， meanwhile the propagation characteristics presented a difference in different months and it spreads fastest in June and slowest in August.The diurnal variation of convective activity showed a unimodal distribution of frequency with peak region at 16:00 -17:00 （Beijing Time）.It's also showed in the occurrence and development of convection in different terrain occurrence and development in different terrain conditions with the high frequency of thermal convection mainly at high altitude area in the afternoon and presentation in the mountain， river valley， basin and plain respectively at night.The diurnal variation of convective storms in different months was obviously different.The influence of solar heating and topographic forcing on convective storms in the afternoon of June was the most significant， while the response of convective storms in the night of July and August was higher to the complex topography of the plateau slope.The propagation direction of the well-organized storm in the afternoon was closely related to the extension and slope direction of the mountain， and was closely related to the prevailing winds at 500 hPa at night.More than 90% convective storms lasted less than 36 minutes， and only 1% lasted longer than 1 hour.
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