In this study, the seasonal transition of precipitation over the middle and lower reaches of the Yang-tze River Valley (YRV) from late spring to early summer is investigated. The results show that the seasonal transit...In this study, the seasonal transition of precipitation over the middle and lower reaches of the Yang-tze River Valley (YRV) from late spring to early summer is investigated. The results show that the seasonal transition of precipitation exhibits multi-modes. One of these modes is characterized by an abrupt transition from drought to flood (ATDF) over the middle and lower reaches of the YRV in the seasonal transition of precipitation. It is shown that the ATDF event from May to June 2011 is simply one prominent case of the ATDF mode. The ATDF mode exhibits an obvious decadal variability. The mode has occurred more frequently since 1979, and its amplitude has apparently strengthened since 1994. From the climatic view, the ATDF mode configures a typical seasonal circulation transition from winter to summer, for which the winter circulations are prolonged, and the summer circulations with the rainy season are built up early over the YRV.展开更多
Based on monthly precipitation data during 1961-2008 in 50 stations in Fushun,drought and flood indicators of three counties were calculated with Z index method. The geographical and seasonal distribution characterist...Based on monthly precipitation data during 1961-2008 in 50 stations in Fushun,drought and flood indicators of three counties were calculated with Z index method. The geographical and seasonal distribution characteristics of Fushun were analyzed,and so was the impact of droughts and floods on food production. It shows that,since 1961,there are 7 poor harvest years in Fushun,with quadrennial caused by continuous seasonal floods or droughts,two years by year drought,one year by summer flood.展开更多
It has been shown by the observed data that during the early 1990′s, the severe disastrous climate occurred in East Asia. In the summer of 1991, severe flood occurred in the Yangtze River and the Huaihe River basin o...It has been shown by the observed data that during the early 1990′s, the severe disastrous climate occurred in East Asia. In the summer of 1991, severe flood occurred in the Yangtze River and the Huaihe River basin of China and in South Korea, and it also appeared in South Korea in the summer of 1993. However, in the summer of 1994, a dry and hot summer was caused in the Huaihe River basin of China and in R. O. K.. In order to investigate the seasonal predictability of the summer droughts and floods during the early 1990′s in East Asia, the seasonal prediction experiments of the summer droughts and floods in the summers of 1991-1994 in East Asia have been made by using the Institute of Atmopsheric Physics-Two-Level General Circulation Model (IAP-L2 AGCM), the IAP-Atmosphere/Ocean Coupled Model (IAP-CGCM) and the IAP-L2 AGCM including a filtering scheme, respectively. Compared with the observational facts, it is shown that the IAP-L2 AGCM or IAP-CGCM has some predictability for the summer droughts and floods during the early 1990′s in East Asia, especially for the severe droughts and floods in China and R. O. K.. In this study, a filtering scheme is used to improve the seasonal prediction experiments of the summer droughts and floods during the early 1990′s in East Asia. The predicted results show that the filtering scheme to remain the planetary-scale disturbances is an effective method for the improvement of the seasonal prediction of the summer droughts and floods in East Asia.展开更多
[Objective]The research aimed to analyze precipitation change and agricultural drought and flood degrees during crop growth season in Binzhou.[Method]Based on monthly rainfall and average temperature data at Binzhou m...[Objective]The research aimed to analyze precipitation change and agricultural drought and flood degrees during crop growth season in Binzhou.[Method]Based on monthly rainfall and average temperature data at Binzhou meteorological observatory during March-November of1981-2010,by using linear regression,climatic tendency rate and dry-wet coefficient,precipitation change and agricultural drought and flood degrees during crop growth season of the past 30 years in Binzhou were analyzed from natural precipitation tendency change and satisfaction degree of agricultural water demand during crop growth season.[Result]In the past 30 years,precipitation during growth season in Binzhou presented increasing tendency.Spring,summer and autumn precipitation all increased somewhat,especially summer precipitation.Monthly average rainfall distribution was very uneven,and rainfall in July and August was more.In the past 30 years,average dry-wet coefficient K value during crop growth season in Binzhou was 0.60,it overall belonged to moderate drought climate type,and occurrence frequency of drought was 97%.It belonged to serious drought climate type in spring and autumn and light drought climate type in summer.Dry-wet coefficient presented rising tendency,illustrating that climate was developing toward wet direction.Seen from mean over the years,except humid in July,it was over light drought in other months.[Conclusion]Climate was overall arid during crop growth season in Binzhou,but precipitation somewhat increased in the past 30 years.Therefore,we suggested that artificial rainfall work should be enhanced.展开更多
基于Climatic Research Unit(简称CRU)的高分辨率月值平均潜在蒸发量和降水资料,构建我国近112年干燥度指数,采用线性倾向估计、Morlet小波分析等方法研究我国东部气候干燥度南北之间的差异及其各自的变化特征。结果表明,近一个多世纪以...基于Climatic Research Unit(简称CRU)的高分辨率月值平均潜在蒸发量和降水资料,构建我国近112年干燥度指数,采用线性倾向估计、Morlet小波分析等方法研究我国东部气候干燥度南北之间的差异及其各自的变化特征。结果表明,近一个多世纪以来,中国东部整体呈现变干趋势,20世纪60年代之后干旱化趋势更加明显。相比南方,北方气候干燥程度对降水的依赖性更强,干旱化速度更大,旱涝随时间的转变更为剧烈;南湿北干的差异进一步扩大,温度的升高对潜在蒸发量的增强作用加剧了干旱化程度。我国东部地区干湿季变化存在差异,干季年际年代际变率明显高于湿季,且干季变化较湿季具有更好的南北空间一致性;南北干湿季的出现时间在近半个世纪也有所变化,干季延后到来,湿季则提前到来的现象,说明干湿季的持续时间均有所延长;此外近半个世纪,北方干湿季均呈现明显的干旱化,南方未表现出类似特征。展开更多
基金supported by the National Basic Research Program of China (Grant No.2009CB421401)the National Key Technologies R&D Program of China (Grant No. 2009BAC51B02)+1 种基金the National Natural Science Foundation of China (Grant No. 40975022)the Special Scien-tific Research Fund of the Meteorological Public Welfare Profession of China (Grant No. GYHY200906018)
文摘In this study, the seasonal transition of precipitation over the middle and lower reaches of the Yang-tze River Valley (YRV) from late spring to early summer is investigated. The results show that the seasonal transition of precipitation exhibits multi-modes. One of these modes is characterized by an abrupt transition from drought to flood (ATDF) over the middle and lower reaches of the YRV in the seasonal transition of precipitation. It is shown that the ATDF event from May to June 2011 is simply one prominent case of the ATDF mode. The ATDF mode exhibits an obvious decadal variability. The mode has occurred more frequently since 1979, and its amplitude has apparently strengthened since 1994. From the climatic view, the ATDF mode configures a typical seasonal circulation transition from winter to summer, for which the winter circulations are prolonged, and the summer circulations with the rainy season are built up early over the YRV.
基金Supported by Fushun Government Financed Subject(20071209)
文摘Based on monthly precipitation data during 1961-2008 in 50 stations in Fushun,drought and flood indicators of three counties were calculated with Z index method. The geographical and seasonal distribution characteristics of Fushun were analyzed,and so was the impact of droughts and floods on food production. It shows that,since 1961,there are 7 poor harvest years in Fushun,with quadrennial caused by continuous seasonal floods or droughts,two years by year drought,one year by summer flood.
文摘It has been shown by the observed data that during the early 1990′s, the severe disastrous climate occurred in East Asia. In the summer of 1991, severe flood occurred in the Yangtze River and the Huaihe River basin of China and in South Korea, and it also appeared in South Korea in the summer of 1993. However, in the summer of 1994, a dry and hot summer was caused in the Huaihe River basin of China and in R. O. K.. In order to investigate the seasonal predictability of the summer droughts and floods during the early 1990′s in East Asia, the seasonal prediction experiments of the summer droughts and floods in the summers of 1991-1994 in East Asia have been made by using the Institute of Atmopsheric Physics-Two-Level General Circulation Model (IAP-L2 AGCM), the IAP-Atmosphere/Ocean Coupled Model (IAP-CGCM) and the IAP-L2 AGCM including a filtering scheme, respectively. Compared with the observational facts, it is shown that the IAP-L2 AGCM or IAP-CGCM has some predictability for the summer droughts and floods during the early 1990′s in East Asia, especially for the severe droughts and floods in China and R. O. K.. In this study, a filtering scheme is used to improve the seasonal prediction experiments of the summer droughts and floods during the early 1990′s in East Asia. The predicted results show that the filtering scheme to remain the planetary-scale disturbances is an effective method for the improvement of the seasonal prediction of the summer droughts and floods in East Asia.
文摘[Objective]The research aimed to analyze precipitation change and agricultural drought and flood degrees during crop growth season in Binzhou.[Method]Based on monthly rainfall and average temperature data at Binzhou meteorological observatory during March-November of1981-2010,by using linear regression,climatic tendency rate and dry-wet coefficient,precipitation change and agricultural drought and flood degrees during crop growth season of the past 30 years in Binzhou were analyzed from natural precipitation tendency change and satisfaction degree of agricultural water demand during crop growth season.[Result]In the past 30 years,precipitation during growth season in Binzhou presented increasing tendency.Spring,summer and autumn precipitation all increased somewhat,especially summer precipitation.Monthly average rainfall distribution was very uneven,and rainfall in July and August was more.In the past 30 years,average dry-wet coefficient K value during crop growth season in Binzhou was 0.60,it overall belonged to moderate drought climate type,and occurrence frequency of drought was 97%.It belonged to serious drought climate type in spring and autumn and light drought climate type in summer.Dry-wet coefficient presented rising tendency,illustrating that climate was developing toward wet direction.Seen from mean over the years,except humid in July,it was over light drought in other months.[Conclusion]Climate was overall arid during crop growth season in Binzhou,but precipitation somewhat increased in the past 30 years.Therefore,we suggested that artificial rainfall work should be enhanced.
文摘基于Climatic Research Unit(简称CRU)的高分辨率月值平均潜在蒸发量和降水资料,构建我国近112年干燥度指数,采用线性倾向估计、Morlet小波分析等方法研究我国东部气候干燥度南北之间的差异及其各自的变化特征。结果表明,近一个多世纪以来,中国东部整体呈现变干趋势,20世纪60年代之后干旱化趋势更加明显。相比南方,北方气候干燥程度对降水的依赖性更强,干旱化速度更大,旱涝随时间的转变更为剧烈;南湿北干的差异进一步扩大,温度的升高对潜在蒸发量的增强作用加剧了干旱化程度。我国东部地区干湿季变化存在差异,干季年际年代际变率明显高于湿季,且干季变化较湿季具有更好的南北空间一致性;南北干湿季的出现时间在近半个世纪也有所变化,干季延后到来,湿季则提前到来的现象,说明干湿季的持续时间均有所延长;此外近半个世纪,北方干湿季均呈现明显的干旱化,南方未表现出类似特征。
