塔克拉玛干沙漠腹地降雨特征分析

Analysis of Rainfall Variation In Hinterland of Taklamakan Desert

[目的]探究塔克拉玛干沙漠腹地降雨特征,为该区生态环境建设提供支持。[方法]利用塔中气象站2005—2014年4—10月的逐小时降水量资料,通过对雨强、降水量、雨日等综合分析塔中地区近10a降雨特征。[结果]研究区逐小时降水量和降水频次在时次分布上具有较好的一致性,23:00至翌日8:00时为高值区,17:00到22:00为低值区;1h雨强(用R1表示),降水频次最多是R1≤0.5mm的降水,占总频次的64.5%,其次是0.6mm≤R1≤1.5mm,但从对降水的贡献率来看0.6mm≤R1≤1.5mm的贡献率最高,占总降水量的26.4%,其次是R1≥4.6mm;不同量级降水过程(用R表示),0.1mm≤R≤2mm的降水过程发生频次最多,R≥6.1mm降水过程对降水量贡献率最大,占总降水量的52.6%;夜间为降水的易发时段;R≥6.1mm的降水过程主要集中在5—7月,尤其多发生在6月,且有1/2发生在前半夜;5h以下的降水占了降水总数的85.5%。[结论]研究区的降水主要以短时夜雨为主,近年来≥6.1mm雨日呈增加且稳定趋势,因此沙漠地区有出现大降水的可能性。

[Objedtive] The characteristics of precipitation in the hinterland of Taklimakan Desert were explored to provide support for the construction of ecological environment.[Methods] Based on the hourly precipitation data from April to October during 2005-2014 from Tazhong meteorological station, the rainfall intensity, precipitation and the days of precipitation, etc. were analyzed to describe the rainfall characteristics of Tazhong area.[Results] The diurnal variations of hourly precipitation and rainfall frequency were consistent in the study area. The peaks of hourly rainfall and rainfall frequency both occurred from 23：00 to 08：00, and the minimum value occurred from 17：00 to 22：00. The frequency of rainfall（represented by R1）≤0.5 mm were the most and accounted for 64.5% of all rainfall events, the following intensities were 0.6 mm≤R1≤1.5 mm and R1≥4.6 mm. The contribution of 0.6 mm≤R1≤1.5 mm was the highest and accounted for 26.4% of the total precipitation amount. In terms of the magnitude of precipitation（R）, light rain or less of 0.1 mm≤R≤2 mm occurred the most, but R≥6.1 mm precipitation events had the highest contribution to the total precipitation, the value was 52.6%. The rain was more frequently occurred in night time. Moderate rain focused from May to July, especially in June, half of that occurred in the first half of night. The precipitation duration of less than or equal to 5 h accounted for 85.5%.[Conclusion] The precipitation in the study area were mainly composed of short-time night-rain. In recent years,the precipitation of≥6.1 mm showed a trend of stable increase, so the large precipitation in desert area may be possible.