【摘要】 研究区域尺度极端降水时空格局有助于区域整体性评估降水可能带来的风险。以三江平原21个气象站点1979—2014年逐日降水量观测资料为基础,选取了11个极端降水指数,应用气候倾向率、克里金插值法、Mann-Kendall非参数检验、累积距平、R/S分析法和相关分析法,从降水强度、降水频率等方面分析了近40 a三江平原极端降水时空变化特征,并对极端降水指数进行了趋势预测。研究表明:(1)近40 a三江平原极端降水指数整体呈减少趋势,且降水量减少主要表现为降水强度降低;其中持续干燥日数(CDD)、普通日降水强度(SDII)、5日最大降水量(RX5day)存在明显突变现象,均在2000年左右发生"由多到少"的突变;(2)极端降水指数变化趋势存在显著空间差异,RX1day,RX5day,R99p呈减少趋势的站点所占比例分别为52.4%,61.9%,61.9%;年降水总量(PRCPTOT)整体呈现"西北、东南地区上升趋势显著,东北、西南地区以下降趋势为主"的降水分布格局,极端降水总量(R99P)上升幅度较大的地区主要集中于平原中部的宝清县;(3)根据极端降水指数的历史变化趋势与Hurst指数叠加结果预测可知,未来极端降水指数基本呈上升趋势。研究结果可为三江平原农业区充分利用天然降水、预估农业气象灾害影响提供科学依据。更多还原

【Abstract】 Within the context of climate change, extreme climate events occurred frequently. By using climatic tendency rate, Kriging interpolation method, Mann-Kendall nonparametric statistical test, accumulative distance leveling, R/S analysis, the variation characteristics and trend prediction of extreme precipitation process in the target area were analyzed based on long-term(1979—2014) daily precipitation data from 21 meteorological stations. The results showed a decreasing trend on the extreme precipitation over the past 40 years in the Sanjiang Plain, which was mainly reflected by the precipitation intensity. Moreover, there were obvious mutations in CDD, SDII, and RX5 day. There was a significant spatial difference in the extreme precipitation variation trend. The percentages of sites with decreasing RX1 day, RX5 day and R99 p were 52.4%, 61.9% and 61.9%, respectively. The total annual precipitation(PRCPTOT) was presented as ‘increase in Northwest-Southeast and decrease in Northeast-Southwest’. According to the historical trend of the extreme precipitation index and the prediction of the superposition of the Hurst index, it can be seen that the future extreme precipitation index will present the rising trend in the future. These results can provide scientific basis for making full use of natural precipitation and predicting the influence of agrometeorological disasters in the agricultural area of Sanjiang Plain.更多还原