沿河县汛期短时强降水时空分布特征

The Spatiotemporal Distribution Characteristics of Short-Term Heavy Rainfall during the Flood Season in Yanhe County

摘要: 利用沿河县2014年至2020年汛期(4~10月)含国家站在内的22个站点逐小时降水数据，统计分析沿河县汛期短时强降水时空分布特征，结果表明：1) 沿河县汛期短时强降水发生频次空间分布表现为西北和东南部高值区，中部低值区的特征，且存在三个高值中心，其降水强度空间分布表现为东强西弱，县东南部的高值中心主要以40 mm/h以上短时强降水为主；2) 沿河县汛期短时强降水高发期出现在6~7月，4月和10月为降水强度较弱月份，但平均降水强度却以5月和6月最大；3) 短时强降水日变化表现出明显的夜雨性：频发期主要集中在凌晨2时~次日早上9时，占总站次百分比的51%，且其强度分布表现为夜间降水大于白天；4) 60 mm/h以上强度的短时强降水主要出现在晚上21时~次日早上10时，累计站次达18站次，其余时次仅出现5站次，但早晨发生的短时强降水强度更大、站次更多，进一步表明沿河县短时强降水夜雨性的特征。

Abstract: Using hourly precipitation data from 22 stations including the national station in Yanhe County during the flood season from 2014 to 2020 (April to October), the spatiotemporal distribution characteristics of short-term heavy rainfall in Yanhe County during the flood season were statistically analyzed. The results showed that: 1) The spatial distribution of the frequency of short-term heavy rainfall during flood season in Yanhe County is characterized by high-value areas in the northwest and southeast, and low-value areas in the middle, and there are three high-value centers, whose spatial distribution of precipitation intensity is strong in the east and weak in the west, and the high-value center in the southeast of the county is mainly dominated by short-term heavy rainfall above 40 mm/h; 2) The high occurrence period of short-term heavy rainfall in Yanhe County during the flood season occurred in June to July, and the rainfall intensity was weak in April and October, but the average rainfall intensity was the highest in May and June; 3) The diurnal variation of short-term heavy rainfall showed obvious night rain: the frequent period was mainly concentrated from 2 am to 9 am the next day, accounting for 51% of the total station, and its intensity distribution was greater at night than during the day; 4) The short-term heavy rainfall with an intensity above 60 mm/h mainly occurred from 21 pm to 10 am the next day, with a total of 18 stops, and only 5 stops in the rest of the day. However, the short-term heavy rainfall occurred in the morning with greater intensity and more stops, further indicating the characteristics of night rain of short-term heavy rainfall in Yanhe County.