摘要
利用玉树站1953—2011年59年的常规地面降水资料,分析了玉树地区夏季昼夜降水的特征,并利用2004—2011年8年间逐时降水资料,分析了该地区夏季逐时降水特征。结果表明:1953—2011年59年间玉树结古地区夏季降水夜雨特征较为明显,夜雨率达到66%。在小雨量级,夏季昼雨频次都大于夜雨频次,但在小到中雨量级时,夜雨发生频次开始增多并多于昼雨频次,而且这一增多趋势在随着降水量的增多而迅速增大。夏季平均而言,85%的中到大雨和92%的大雨过程均发生在夜间时段内,且发生在7,8月夜间较6月夜间多。夏季不同小时雨强的出现频次,夜间均大于白天,夜雨频次占总降水频次的60%。降水多发时段为19时至24时及凌晨3时至7时之间,少发时段为11时至13时。小波分析表明:昼夜降水变化具有5—10年的短时间尺度变化周期及15年左右的长时间尺度的变化周期。夜雨的周期性在80年代后有所加强,而昼雨则相反。
Based on the routine surface observation data from 1953 to 2011 at Yushu Station, the characteris- tics of daytime and night precipitation over this region in summer were studied. Moreover, the features of hourly precipitation were analyzed by used the hourly precipitation of recent years from 2004 to 2011.The results show the rate of night rain reaches 66% in summer in the past 59a. In summer, the frequency of daytime precipitation is more than the night precipitation under the light rain but the frequency of night precipitation will increase rapidly when the precipitation increased. More than 85% moderate--to--heavy rain and 92% heavy rain hap- pened in night for summer mean, and these cases in July and August are more than June. Whatever the hour rainfall density is, the frequency of night rain are more than in daytime rain and account for 60% of the total precipitation. The high-frequency periods are 19p.m -24p.m and 3a.m - 7a.m and the low-frequency period is 1 lp.m-13p.m. The daytime and night precipitation have 5-10a short period and 15a long time scale period. After the 80s, the periodical energy of night rainfall increased while the daily precipitation deceased.
出处
《青海气象》
2013年第1期32-36,共5页
Journal of Qinghai Meteorology
关键词
昼夜降水
小时雨强
周期
night and daytime precipitation
hourly rainfall density
period
