喀什地区降水(雨雪)的日变化特征

Interdiurnal variation characteristics of precipitation(rain and snow)in Kashi Prefecture

利用2010—2017年1~12月新疆喀什地区10个气象站逐小时降水资料,分析统计喀什地区近8 a降雨雪(以下统称降水)日变化特征。结果表明:(1)喀什地区全年降水量和降水频次日变化存在明显的波动,总体上呈现“正弦波”一峰一谷特征,降水量峰值出现在03:00(北京时,下同),谷值出现在18:00;降水频次峰值出现在04:00,谷值出现在18:00;两者峰谷值出现时间接近。(2)2010—2017年喀什地区全年降水量和降水频次呈明显的增加趋势;而降水强度年际变化趋于平缓,无明显变化。(3)降水强度日变化趋势与降水量、降水频次并不存在一致性。(4)喀什地区全年降水主要以短时段降水为主,其中,持续1 h降水次数为最大值,但降水量和贡献率最大值却同出现在2 h和6 h持续降水中。全年降水主要以后半夜和上午开始的降水过程为主导,且仍主要为短时段降水。

The most obvious feature of measuring climate changes in one or more regions is precipitation,and the magnitude and distribution of precipitation directly restricts the development of the national economy and the bumper harvest of agricultural production,and also closely relates to the lives of the individuals.The Kashi Prefecture,Xinjiang,China is located in the abdomen of Central Asia,and it belongs to the warm temperate continental arid climate zone,with distinct four seasons and sufficient sunshine.Its annual and daily temperature changes are of great disparity,the precipitation is less and the evaporation is strong.Although the overall precipitation in Xinjiang is relatively small,the contribution of extreme precipitation to the total amount of precipitation is still on the rise.Previous research scales for precipitation in Kashi mainly focused on monthly precipitation or diurnal precipitation changes.In the context of global warming,it is particularly important to study the annual variation of precipitation over the whole year,which is not only extremely important for the meteorological services in the designated region,but also plays a vitally important guiding role in artificial flood control and rain enhancement(snow) operations,and even has an important significance for understanding the climate characteristics and trends of Xinjiang.This paper utilizes the hourly precipitation data of 10 meteorological stations in the Kashi Prefecture from January to December 2010 to analyze the daily variation characteristics(from the precipitation,precipitation frequency,precipitation intensity and precipitation over time) of precipitation(rain and snow) in the Kashi Prefecture.The results show as follows:(1) There are obvious fluctuations in the annual variation of precipitation and precipitation frequency in Kashi,and overall it formed a sinusoidal wave shape characterized by one peak and one valley,and the peak of precipitation appears at 03:00 AM(Beijing time,the same below) and the valley at 18:00 PM;the peak frequency of precipitation appears at 04:00 PM and the valley at 18:00 PM.(2) From 2010 to 2017,the annual precipitation and precipitation frequency in the Kashi region showed a significant increase trend;while the annual variation of precipitation intensity tended to be gentle and had no obvious change.(3) There is no consistency between the daily variation trend of precipitation intensity and the frequency of precipitation and the amount of precipitation.(4) The precipitation in the whole year depends mainly on short-period precipitation.Among them,most of the precipitations lasted for about 1 hour,and the precipitations with 2 hours duration contributed the most to the amount of precipitation yet the precipitations of 6 hours duration ranked first from the contribution ratio perspective.The precipitation in the Kashi region is mainly dominated by precipitation in the middle of the night and in the morning.