Based on the property of entropy,a new index Q was defined to measure the temporal concentration property of summertime daily rainfall in China,based on daily precipitation data collected at 553 observation stations i...Based on the property of entropy,a new index Q was defined to measure the temporal concentration property of summertime daily rainfall in China,based on daily precipitation data collected at 553 observation stations in China during 1961–2010.Furthermore,changes in the temporal concentration property of summer precipitation in China were investigated.The results indicate that the regions with larger Q values were located in most parts of Northwest China and the north of the Yellow River,where daily precipitation tended to become temporally concentrated during the study period.On the contrary,smaller Q values were found in eastern Tibetan Plateau,southeastern Northwest China,and most parts of Southwest and South China.The most obvious increasing trend of Q index was found in South China and most parts of Southwest China,where precipitation showed a temporal concentration trend.However,a decreasing trend of Q index was found in Northwest China,the Tibetan Plateau,and the north of the Huaihe River.Variations of the Q index and the summer rainfall total during 1961–2010 in China both exhibited an increasing trend,implying larger temporal variability in rainfall attributes.It is illustrated that the summer precipitation in general became more temporally concentrated with more intense rainfall events and wetter days.展开更多
Precipitation heterogeneity has a nontrivial influence on human life. Many studies have analyzed precipitation heterogeneity but none have proposed a systematic graded index for its evaluation, and therefore, its true...Precipitation heterogeneity has a nontrivial influence on human life. Many studies have analyzed precipitation heterogeneity but none have proposed a systematic graded index for its evaluation, and therefore, its true characteristics have not been expressed. After comparisons of various methods, the precipitation concentration degree(PCD) method was selected to study precipitation heterogeneity. In addition to the PCD, normal distribution functions, cumulative frequencies, and percentiles were used to establish a graded index for evaluating precipitation heterogeneity. A comprehensive evaluation of precipitation heterogeneity was performed, and its spatiotemporal variation in China from 1960 to 2013 was analyzed. The results indicated that(1) seven categories of precipitation heterogeneity were identified(high centralization, moderate centralization, mild centralization, normal, mild dispersion, moderate dispersion, and high dispersion) and(2) during the study period, the precipitation in more parts of China tended to be normal or dispersed, which is beneficial to human activities.展开更多
在全球变暖和人类活动的背景下,降水在年内分布上发生了比较大的变化,对人民生产生活产生了巨大的影响,这一影响在城市化较高的地区尤为明显。基于多源降水数据(降水产品数据和气象站点数据)和夜间灯光数据,选定中国的长三角城市群作为...在全球变暖和人类活动的背景下,降水在年内分布上发生了比较大的变化,对人民生产生活产生了巨大的影响,这一影响在城市化较高的地区尤为明显。基于多源降水数据(降水产品数据和气象站点数据)和夜间灯光数据,选定中国的长三角城市群作为研究区域,将基尼系数(Gini Index,GI)作为降水集中度的指标,利用Theil-Sen Median斜率估计和Mann-Kendall显著性检验进行趋势分析,最后通过相关性分析探究城市化程度与降水集中度的关系。研究结果表明:(1)CHIRPS(Climate Hazards Group InfraRed Precipitation with Station Data)数据计算得到的GI与站点数据结果的均方根误差为0.036,远小于CMFD数据(0.067)和MSWEP数据(0.083)的结果,表明CHIRPS数据具有最佳的适用性;(2)长三角城市群的降水不均匀性从南向北逐渐增加,并在城市群中部和西部呈现出显著上升的趋势,研究区域内的降水年内分布将会朝着集中分布的方向发展,极端降水事件出现的可能性增加;(3)城市化对降水集中度主要起到促进作用,城市的快速发展使得降水不均匀性增强,并且在城市群内的南京市、无锡市和镇江市等地区更为显著,更有可能发生城市内涝等灾害。研究对于城市的防洪设计、城市道路排水管道的设计和城市防洪应急响应预案的编制具有参考意义。展开更多
基金Supported by the National Natural Science Foundation of China(41575094 and 41275092)Project for Postgraduate Scientific Research and Innovation of Jiangsu Province(KYLX_0842 and CXZZ12-0485)Innovation Program of the State Key Laboratory of Severe Weather,Chinese Academy of Meteorological Sciences(2015LASW-A03)
文摘Based on the property of entropy,a new index Q was defined to measure the temporal concentration property of summertime daily rainfall in China,based on daily precipitation data collected at 553 observation stations in China during 1961–2010.Furthermore,changes in the temporal concentration property of summer precipitation in China were investigated.The results indicate that the regions with larger Q values were located in most parts of Northwest China and the north of the Yellow River,where daily precipitation tended to become temporally concentrated during the study period.On the contrary,smaller Q values were found in eastern Tibetan Plateau,southeastern Northwest China,and most parts of Southwest and South China.The most obvious increasing trend of Q index was found in South China and most parts of Southwest China,where precipitation showed a temporal concentration trend.However,a decreasing trend of Q index was found in Northwest China,the Tibetan Plateau,and the north of the Huaihe River.Variations of the Q index and the summer rainfall total during 1961–2010 in China both exhibited an increasing trend,implying larger temporal variability in rainfall attributes.It is illustrated that the summer precipitation in general became more temporally concentrated with more intense rainfall events and wetter days.
基金National Natural Science Foundation of China,No.41171090National Social Science Foundation of China,No.14AZD094,No.14XSK019
文摘Precipitation heterogeneity has a nontrivial influence on human life. Many studies have analyzed precipitation heterogeneity but none have proposed a systematic graded index for its evaluation, and therefore, its true characteristics have not been expressed. After comparisons of various methods, the precipitation concentration degree(PCD) method was selected to study precipitation heterogeneity. In addition to the PCD, normal distribution functions, cumulative frequencies, and percentiles were used to establish a graded index for evaluating precipitation heterogeneity. A comprehensive evaluation of precipitation heterogeneity was performed, and its spatiotemporal variation in China from 1960 to 2013 was analyzed. The results indicated that(1) seven categories of precipitation heterogeneity were identified(high centralization, moderate centralization, mild centralization, normal, mild dispersion, moderate dispersion, and high dispersion) and(2) during the study period, the precipitation in more parts of China tended to be normal or dispersed, which is beneficial to human activities.
文摘在全球变暖和人类活动的背景下,降水在年内分布上发生了比较大的变化,对人民生产生活产生了巨大的影响,这一影响在城市化较高的地区尤为明显。基于多源降水数据(降水产品数据和气象站点数据)和夜间灯光数据,选定中国的长三角城市群作为研究区域,将基尼系数(Gini Index,GI)作为降水集中度的指标,利用Theil-Sen Median斜率估计和Mann-Kendall显著性检验进行趋势分析,最后通过相关性分析探究城市化程度与降水集中度的关系。研究结果表明:(1)CHIRPS(Climate Hazards Group InfraRed Precipitation with Station Data)数据计算得到的GI与站点数据结果的均方根误差为0.036,远小于CMFD数据(0.067)和MSWEP数据(0.083)的结果,表明CHIRPS数据具有最佳的适用性;(2)长三角城市群的降水不均匀性从南向北逐渐增加,并在城市群中部和西部呈现出显著上升的趋势,研究区域内的降水年内分布将会朝着集中分布的方向发展,极端降水事件出现的可能性增加;(3)城市化对降水集中度主要起到促进作用,城市的快速发展使得降水不均匀性增强,并且在城市群内的南京市、无锡市和镇江市等地区更为显著,更有可能发生城市内涝等灾害。研究对于城市的防洪设计、城市道路排水管道的设计和城市防洪应急响应预案的编制具有参考意义。
