阿勒泰单站近13a夏季小时降水日变化特征

Abstract

利用阿勒泰基准气候站2005~2017a夏季(6~8月)逐小时降水资料揭示了阿勒泰单站夏季降水的日变化特征，结果表明：1) 2005~2017a夏季(6~8月)阿勒泰单站降水量日峰值呈双峰型，日峰值出现在早晨和傍晚；降水频率的日峰值出现在上午12:00；降水强度的日峰值出现在傍晚19:00。2) 2005~2017a夏季(6~8月)阿勒泰单站出现短时降水达305次，中时降水31次，长时降水22次；短时降水对夏季降水的贡献率最大，其次为长时降水，中时降水贡献率最小。3) 短时降水的日峰值最大，出现在傍晚；长时降水的日峰值其次，出现在早晨；中时降水量的日峰值最小，出现在傍晚。短时降水频率的日峰值明显高于中时降水和长时降水，同时三者的日峰值均出现在12:00。短时降水和中时降水的降水强度日峰值出现在傍晚，长时降水的降水强度日峰值出现在午后。4) 1级降水日峰值大于2级和3级，1级和3级降水量日峰值出现在午后至傍晚，2级降水量日峰值出现在清晨。 In this paper, the characteristics of daily precipitation variation in the Altay region in summer were investigated, based on the hourly precipitation data from the Altay benchmark climatologi-cal station during June to August between 2005 and 2017. The results showed that the amount of precipitation in the Altay region was presented as a double-summit variation, of which two summits appeared in the morning and evening. The peak value of precipitation frequency was at around 12:00 and the peak value of precipitation intensity was at around 19:00. The rainfall types included short-duration rainfalls (305 times), mid-duration rainfalls (31 times) and long-duration rainfalls (22 times), among which the contribution of short-duration rainfalls was the most to summer precipitation, while mid-duration rainfalls contributed the least. Moreover, the peak value of short-duration rainfalls appeared in the evening, as well as mid-duration rainfalls, while that of long-duration rainfalls was detected in the morning. Although the daily peak value of frequency of short-duration rainfall was apparently higher than that of mid-duration and long-duration rainfalls, the peak values of these 3 types all appeared around 12:00. The precipitation intensity of short-duration and mid-duration rainfalls peaked in the evening while that of long-duration rainfall peaked in the afternoon. Interestingly, when categorized into 3 levels of amount of precipitation, the daily peak value of level 1 was higher than those of levels 2 and 3. The peaks of levels 1 and 3 took place in the afternoon, while that of level 2 was in the early morning.