The currently used hydrological forecast system in China is mainly focused on flood,and the flood forecasting frameworks are typically based on point discharge measurements and predictions at discrete locations,hence ...The currently used hydrological forecast system in China is mainly focused on flood,and the flood forecasting frameworks are typically based on point discharge measurements and predictions at discrete locations,hence they can’t provide spatio-temporal information of various hydrological elements,such as surface runoff,soil moisture,ground water table,and flood inundation extents over large scales and at high spatial resolutions.The use of distributed hydrological model has recently appeared to be the most suitable option to bridge this gap.An open source GIS-based distributed hydrological forecast system was established recently,and the watershed delineation and hydrological modelling were integrated together seamlessly.The time and human consuming work of processing the spatial data in building distributed hydrological model could be reduced significantly,and the spatial distribution of hydrological information could be quickly simulated and predicted using this system.The system was applied successfully to forecast the flood caused by super strong typhoon"Mangkhut"which attacked the south China in2018.展开更多
Oceanic evaporation via the East Asian Monsoon （EAM） has been regarded as the major source of precipitation over China, but a recent study estimated that terrestrial evaporation might contribute up to 80% of the pre...Oceanic evaporation via the East Asian Monsoon （EAM） has been regarded as the major source of precipitation over China, but a recent study estimated that terrestrial evaporation might contribute up to 80% of the precipitation in the country. To explain the contra- diction, this study presents a comprehensive analysis of the contribution of oceanic and terrestrial evaporation to atmospheric moisture and precipitation in China＇s major river basins. The results show that from 1980 to 2010, the mean annual atmospheric moisture （precipitable water） over China was 13.7 mm, 39% of which originates from oceanic evaporation and 61% from terrestrial evaporation. The mean annual precipitation was 737 mm, 43% of which originates from oceanic evaporation and 57% from terrestrial evaporation. Oceanic evaporation makes a greater contribution to atmospheric moisture and precipitation in the East Asian Monsoon Region in South and East China than terrestrial evaporation does. Particularly, for the Pearl River and southeastern rivers, oceanic evaporation contributes approximately 65% of annual precipitation and more than 70% of summer precipitation. Meanwhile, terrestrial evaporation contributes more precipitation in northwest China due to the westerly wind. For the northwestern rivers, terrestrial evaporation from the Eurasian continents contributes more than 70% of precipitation. There is a linear relation between mean annual precipitation and the contribution of oceanic evaporation to precipitation, with a correlation coefficient of 0.92, among the ten major river basins in China.展开更多
We considered the following semiparametric regres-sion model yi = X iT β+ s ( t i ) + ei (i =1,2,,n). First,the general-ized ridge estimators of both parameters and non-parameters are given without a restrained desig...We considered the following semiparametric regres-sion model yi = X iT β+ s ( t i ) + ei (i =1,2,,n). First,the general-ized ridge estimators of both parameters and non-parameters are given without a restrained design matrix. Second,the generalized ridge estimator will be compared with the penalized least squares estimator under a mean squares error,and some conditions in which the former excels the latter are given. Finally,the validity and feasibility of the method is illustrated by a simulation example.展开更多
基金supported by the National Key Research and Development Program of China(Grant No.2018YFC1508100)
文摘The currently used hydrological forecast system in China is mainly focused on flood,and the flood forecasting frameworks are typically based on point discharge measurements and predictions at discrete locations,hence they can’t provide spatio-temporal information of various hydrological elements,such as surface runoff,soil moisture,ground water table,and flood inundation extents over large scales and at high spatial resolutions.The use of distributed hydrological model has recently appeared to be the most suitable option to bridge this gap.An open source GIS-based distributed hydrological forecast system was established recently,and the watershed delineation and hydrological modelling were integrated together seamlessly.The time and human consuming work of processing the spatial data in building distributed hydrological model could be reduced significantly,and the spatial distribution of hydrological information could be quickly simulated and predicted using this system.The system was applied successfully to forecast the flood caused by super strong typhoon"Mangkhut"which attacked the south China in2018.
基金The authors would like to thank Dr. Ruud van der Ent for helping to set up the water accounting model, and Prof. Glenn Patterson, Mr. Ragai Wanis and Dr. Junmei Lv for the helpful comments to improve the paper. The research has been financially supported by the National Natural Science Foundation of China （Grant Nos. 51409145 and 51179085） and the National Basic Research Program of China （Nos. 2011BAC09B07 and 2013BAB05B03）.
文摘Oceanic evaporation via the East Asian Monsoon （EAM） has been regarded as the major source of precipitation over China, but a recent study estimated that terrestrial evaporation might contribute up to 80% of the precipitation in the country. To explain the contra- diction, this study presents a comprehensive analysis of the contribution of oceanic and terrestrial evaporation to atmospheric moisture and precipitation in China＇s major river basins. The results show that from 1980 to 2010, the mean annual atmospheric moisture （precipitable water） over China was 13.7 mm, 39% of which originates from oceanic evaporation and 61% from terrestrial evaporation. The mean annual precipitation was 737 mm, 43% of which originates from oceanic evaporation and 57% from terrestrial evaporation. Oceanic evaporation makes a greater contribution to atmospheric moisture and precipitation in the East Asian Monsoon Region in South and East China than terrestrial evaporation does. Particularly, for the Pearl River and southeastern rivers, oceanic evaporation contributes approximately 65% of annual precipitation and more than 70% of summer precipitation. Meanwhile, terrestrial evaporation contributes more precipitation in northwest China due to the westerly wind. For the northwestern rivers, terrestrial evaporation from the Eurasian continents contributes more than 70% of precipitation. There is a linear relation between mean annual precipitation and the contribution of oceanic evaporation to precipitation, with a correlation coefficient of 0.92, among the ten major river basins in China.
基金Supported by the Key Project of Chinese Ministry of Educa-tion (209078)the Scientific Research Item of Hubei Provincial Department of Education (D20092207)
文摘We considered the following semiparametric regres-sion model yi = X iT β+ s ( t i ) + ei (i =1,2,,n). First,the general-ized ridge estimators of both parameters and non-parameters are given without a restrained design matrix. Second,the generalized ridge estimator will be compared with the penalized least squares estimator under a mean squares error,and some conditions in which the former excels the latter are given. Finally,the validity and feasibility of the method is illustrated by a simulation example.
