China lies in East-Asian monsoon region,which is one of the well-known active monsoon zones around the world.Monsoon anomaly results in frequent natural disasters,such as drought, torrential rain and flood.In 1998,joi...China lies in East-Asian monsoon region,which is one of the well-known active monsoon zones around the world.Monsoon anomaly results in frequent natural disasters,such as drought, torrential rain and flood.In 1998,joint intensified observations for 4 major meteorological scientific experiments have been carried out over Chinese major monsoon affected areas.A number of valuable data have been obtained and some observational facts have come out after initial analysis.The present paper is to give an introduction to the 4 major meteorological scientific experiments conducted in 1998 in China.including its origin and scientific goals,implementation and planning,equipment and progress,and initial findings from the important observational facts. It aims to provide a comprehensive report on the progress of the above experiments for those who are interested in.展开更多
A coupled general circulation model in a zonal belt is used to simulate the variation of circulation features in the process of uplift of the Qinghai-Xizang Plateau.The results reveal that the heating rates of the Pla...A coupled general circulation model in a zonal belt is used to simulate the variation of circulation features in the process of uplift of the Qinghai-Xizang Plateau.The results reveal that the heating rates of the Plateau increase with the rising of the Plateau topography,and the latent heating compo- nent in the heating field tends to be the most important heating factor.The uplift of the Plateau en- hances the upward motion,intensifies the pressure systems in the high and low level atmosphere,re- inforces Southeast Asia monsoon strength,increases precipitation and severely decreases the surface temperature over the Qinghai-Xizang Plateau. However.the basic structures of the general circulation do not vary much due to the uplift of the Qinghai-Xizang Plateau.and it is the land-sea distribution that is the decisive factor to form the pre- sent circulation pattern and monsoon.Therefore,to simulate the paleoclimate during the geological period people should consider more factors,especially the land-sea distribution.展开更多
The calculating schemes of underlying surface processes in the model described by Li et al.(1989) are modified with inclusion of simple land surface processes and oceanic mixed layer processes, then a simulation on th...The calculating schemes of underlying surface processes in the model described by Li et al.(1989) are modified with inclusion of simple land surface processes and oceanic mixed layer processes, then a simulation on the zonal wind along 90°E from the Northern to the Southern Hemisphere with moun- tains is performed.Comparisons of the results and the observations show that the modified model not only has an excellent stability in calculation but also can better display the seasonal change of the wind field,the ability of the present model is improved as compared with that of the previous one. Based on the simulations,the authors investigate the effects of Qinghai-Xizang Plateau snow cover on the formation of South Asian monsoon by thickcning the snow depth and by increasing the snow albedo.The main results arc as follows:The summer meridional circulation over the south of the Plateau and its vicinity is weakeued,and the precipitation reduced.However,over the northern tropics,the circulation is enhanced, and the ecipitation is increased,and the land and the air above it become warmer,the tropical easterly jet is weakened.展开更多
In order to investigate the formation of the negative vorticity region over the northeast side of the Qinghai Xizang (Tibetan) Plateau,four sets of numerical experiments have been performed in this paper with a quasig...In order to investigate the formation of the negative vorticity region over the northeast side of the Qinghai Xizang (Tibetan) Plateau,four sets of numerical experiments have been performed in this paper with a quasigeostrophic barotropical model considering large-scale topography,diabatic heating and dissipation.The diabatic heating in the model contains a constant forcing and time- varying forcing.The time-varying characters are determined by the continuous evolution of the sensible heat flux at Damxung Station (30°29′N,91°06′E) from 31 May to 4 June 1998.Results suggest that there are three types of processes significantly contributing to the formation of the negative vorticity region over the northeast side of the Qinghai Xizang Plateau,and they are the advection of the anticyclonic vortex at the upstream by the basic flow,the energy dispersion of the cyclonic vortex over the south side of the Plateau,and the strengthening of anticyclonic systems produced by the thermal forcing of the Plateau.展开更多
文摘China lies in East-Asian monsoon region,which is one of the well-known active monsoon zones around the world.Monsoon anomaly results in frequent natural disasters,such as drought, torrential rain and flood.In 1998,joint intensified observations for 4 major meteorological scientific experiments have been carried out over Chinese major monsoon affected areas.A number of valuable data have been obtained and some observational facts have come out after initial analysis.The present paper is to give an introduction to the 4 major meteorological scientific experiments conducted in 1998 in China.including its origin and scientific goals,implementation and planning,equipment and progress,and initial findings from the important observational facts. It aims to provide a comprehensive report on the progress of the above experiments for those who are interested in.
基金Supported by the National Fundamental Key Research Program:Studies on climate dynamics and climate prediction theory.
文摘A coupled general circulation model in a zonal belt is used to simulate the variation of circulation features in the process of uplift of the Qinghai-Xizang Plateau.The results reveal that the heating rates of the Plateau increase with the rising of the Plateau topography,and the latent heating compo- nent in the heating field tends to be the most important heating factor.The uplift of the Plateau en- hances the upward motion,intensifies the pressure systems in the high and low level atmosphere,re- inforces Southeast Asia monsoon strength,increases precipitation and severely decreases the surface temperature over the Qinghai-Xizang Plateau. However.the basic structures of the general circulation do not vary much due to the uplift of the Qinghai-Xizang Plateau.and it is the land-sea distribution that is the decisive factor to form the pre- sent circulation pattern and monsoon.Therefore,to simulate the paleoclimate during the geological period people should consider more factors,especially the land-sea distribution.
文摘The calculating schemes of underlying surface processes in the model described by Li et al.(1989) are modified with inclusion of simple land surface processes and oceanic mixed layer processes, then a simulation on the zonal wind along 90°E from the Northern to the Southern Hemisphere with moun- tains is performed.Comparisons of the results and the observations show that the modified model not only has an excellent stability in calculation but also can better display the seasonal change of the wind field,the ability of the present model is improved as compared with that of the previous one. Based on the simulations,the authors investigate the effects of Qinghai-Xizang Plateau snow cover on the formation of South Asian monsoon by thickcning the snow depth and by increasing the snow albedo.The main results arc as follows:The summer meridional circulation over the south of the Plateau and its vicinity is weakeued,and the precipitation reduced.However,over the northern tropics,the circulation is enhanced, and the ecipitation is increased,and the land and the air above it become warmer,the tropical easterly jet is weakened.
基金the National Key Projects TIPEX 973 China Heavy Rainfall
文摘In order to investigate the formation of the negative vorticity region over the northeast side of the Qinghai Xizang (Tibetan) Plateau,four sets of numerical experiments have been performed in this paper with a quasigeostrophic barotropical model considering large-scale topography,diabatic heating and dissipation.The diabatic heating in the model contains a constant forcing and time- varying forcing.The time-varying characters are determined by the continuous evolution of the sensible heat flux at Damxung Station (30°29′N,91°06′E) from 31 May to 4 June 1998.Results suggest that there are three types of processes significantly contributing to the formation of the negative vorticity region over the northeast side of the Qinghai Xizang Plateau,and they are the advection of the anticyclonic vortex at the upstream by the basic flow,the energy dispersion of the cyclonic vortex over the south side of the Plateau,and the strengthening of anticyclonic systems produced by the thermal forcing of the Plateau.
