广东区域性暴雨过程的定量化评估及气候特征

Quantitative Assessment of Regional Heavy Rainfall Process in Guangdong and Its Climatological Characteristics

利用1961—2017年广东86个地面气象观测站逐日降水资料,定义广东区域性暴雨过程的标准,构建了综合考虑区域暴雨过程持续时间、暴雨范围、最大日降水量和最大过程降水量4个指标的广东区域性暴雨过程综合强度评估方法,由此分析近57年广东区域性暴雨过程次数、强度、雨涝年景等特征和变化。结果表明:近57年来,广东共出现1211次区域性暴雨过程,平均每年21. 2次,主要出现在4—9月,单次过程平均持续时间是2. 3 d;广东区域性暴雨过程的次数和强度存在明显的月际、年际和年代际变化,次数最多出现在5月,强度最大出现在6月;广东雨涝年景指数以0.17/(10 a)的速率显著上升;强和较强等级的广东区域性暴雨过程次数呈显著增加趋势,较弱等级区域性暴雨次数呈显著减少趋势。评估得到广东强雨涝年有5年:2008年、2001年、1973年、1994年、1993年,其中有4年出现在1990年以后。

Using daily precipitation data of 86 meteorological stations in Guangdong from 1961 to 2017, the standard of regional heavy rainfall process is defined. Assessment methods on composite intensity of regional heavy rainfall process in Guangdong are constructed, which take duration, range, maximum daily precipitation and maximum accumulated precipitation during the process into consideration. Characteristics and changes of the frequency, intensity and rain-waterlogging years of regional heavy rainfall process in Guangdong in recent 57 years are studied. 1211 regional heavy rainfall processes are captured, and the annual average frequency is 21. 2 times, There are obvious interannual and interdecadal variations, the highest frequency occurs in 2016(30 times),and the lowest occurs in 1963(13 times). The annual frequency of regional heavy rainfall process in Guangdong increases at a rate of 0. 08/(10 a) in recent 57 years,though not quite significant. The regional heavy rainfall process in Guangdong mainly occurs from April to September, accounting for 81. 9% in the year, among which 45. 4% processes occur in the first flood season(April—June), and 36. 5% processes occur in the second flood season(July —September). The average duration of single regional heavy rainfall process in Guangdong is 2. 3 d, and the longest is 17 d(9-25 June 1968). The average range of a single process covers 20. 3 stations, and the process occurring on 28 January 2016 is observed by the most stations(83). The regional heavy rainfall process with the maximum composite intensity index occurs during 12 —24 June 2005, reaching 1385. 1 mm(Longmen), and this coincides '05. 6' torrential rains and floods in Guangdong. The frequency and strength of the regional heavy rainfall process in Guangdong have intermonth, interannual and inter-decade variations, the frequency in May is the highest, and the strength in June is the highest. The annual harvest index of the rain waterlogging in Guangdong increases obviously at a rate of 0. 17/(10 a) in recent 57 years. Regional heavy rainfall processes of relatively strong and strong class increase significantly, while those of relatively weak class decrease obviously in recent 57 years. Evaluation results show that there are five heavy rain waterlogging years, i.e., 2008, 2001,1973, 1994, 1993.