近60年宁德市降水时空变化及分布特征

Time-space variation and distribution characteristics of precipitation in Ningde City during the past 60 years

基于1960—2019年福建省宁德市9个国家级气象站的逐日降水资料数据,运用气候诊断分析方法,研究该市降水的时空变化及分布特征.结果表明:近60 a宁德市各县市区年降水量为1 598.8~2 086.4 mm,全市平均1 811.1 mm,年降水量气候倾向率为23.737 mm/10 a,线性变化呈不显著增加趋势.降水主要集中在春、夏两季,春、夏两季降水量之和占年降水量的81%,秋、冬两季降水量之和占年降水量的19%.四季降水量的线性变化,春季呈不显著减少趋势,夏、秋、冬三季均呈不显著增加趋势.近60年来各县市区年降水日数为154~219 d,全市平均187 d,年降水日数气候倾向率为-5.984 d/10 a,线性变化呈显著减少趋势.年降水日数在1985年前后有1个突变点,突变发生前后平均年降水日数从200.4 d下降至176.4 d.年降水量和年降水日数的空间分布差异大,最大值和最小值之比分别为1.30倍和1.42倍,二者均呈现从西北山区逐渐向东南沿海减少的分布特征.四季降水量的空间分布,春、冬两季降水量西北部多东南部少,夏、秋两季降水量中部多,东、西部两端少.该市年降水量呈增加趋势,而年降水日数呈减少趋势,预示着未来该市的日降水强度将增大,极端降水事件发生频率将增多,洪涝灾害的风险增加.

Based on the daily precipitation data from nine national meteorological stations in Ningde City, Fujian Province from 1960 to 2019, climate diagnostic analysis was applied to study the time-space variation and distribution characteristics of precipitation in the city. The results show that the annual precipitation in the counties and urban areas of Ningde City in the past 60 a ranged from 1 598.8 to 2 086.4 mm, with a citywide average of 1 811.1 mm and an annual precipitation climate tendency rate of 23.737 mm/10 a, with no significant linear growth. As precipitation concentrated in spring and summer, the sum of spring and summer precipitation accounted for 81% of the annual precipitation, and the sum of autumn and winter accounted for 19%. Regarding the linear variation of precipitation in each season, it demonstrates a slight decreasing trend in spring, and an slight increasing trend in summer, autumn and winter. The annual precipitation days ranged from 154 days to 219 days in districts of the city, whereas the average of the whole city was 187 days. The climate trend rate of annual precipitation days was-5.984 d/10 a, showing a significant linear decreasing trend. With an abrupt change in 1985, The mean annual precipitation days decreased from 200.4 days to 176.4 days. The spatial distribution of annual precipitation amount and annual precipitation days differed widely, with the ratios of maximum and minimum values being 1.30 times and 1.42 times, respectively. The annual precipitation amount and days gradually decreased from the northwest mountainous area to the southeast coastal area. Regarding the spatial distribution in each season, the northwest precipitation was more than the southeast in spring and winter,while the middle area outnumbered the east and the west in summer and autumn. The increasing rate of annual precipitation was consistent with the decreasing rate of annual precipitation days by spatial distribution, signaling an increase in the intensity of daily precipitation, an increase in the frequency of extreme precipitation events and an increased risk of flooding in the city in the future.