Using the data of hourly rainfall from 113 automatic weather stations in Meizhou from 2010 to 2020 and with the methods of statistics and spatial interpolation,this work analyzed the characteristics of spatiotemporal distribution of short-term,intense rains(to be referred to as"SI-rains"hereafter)in the city and the associated terrain effect.The results are shown as follows.There are no significant increases or de-creases in the overall annually averaged frequencies of SI-rains,which fluctuate at a short period of about three years and distribute more in the south and north part than in the central part of the city.Mainly taking place from April to September,the SI-rains are bimodal with the peaks in May and August respectively.They are mainly observed in Pingyuan and Jiaoling in the April-June rainy season and in Fengshun in the Ju-ly-September rainy season,which are governed mainly by the southwest monsoon and tropical synoptic sys-tems.For the diurnal change,the SI-rains frequently happen post-midday till late afternoon and early eve-ning but extreme rain rates are usually two hours later than the onset time.In the April to June rainy season,some kind of nocturnal rain is observed in the northern part of the city.For Meizhou,the SI-rains take place most frequently at the openings of trumpet-shaped windward slopes but least frequently over the plains,low-lying land and basins on the leeward slope of mountains.
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万方数据