In this paper, the summer climate of 1991 in North China is simulated by using the high-resolution regional climate model (RegCM2) and the effects of the grassland desertification on summer drought in the central and ...In this paper, the summer climate of 1991 in North China is simulated by using the high-resolution regional climate model (RegCM2) and the effects of the grassland desertification on summer drought in the central and the northern parts of North China as well as Mongolia are studied. It shows that the regional climate model essentially catches the characteristics on distribution and seasonal variation of the precipitation that keep good agreement with the observation. The desertification makes precipitation in the central part of North China during its flood period decrease obviously in July. The border of the precipitation or the soil moisture reduction in the desertification region extends about one latitude southeastward and beyond the southeast edge of the desertification. Thus, vegetation in the border region approaches desertification further. However, there appears evident difference of variation of precipitation over the whole desertification region. The grassland desertification greatly changes the transfers of fluxes between land and atmosphere. The secondary circulation or secondary circulation cells in the desertification region are excited and as a result moisture transport is changed. The variation of flux transfers between land and atmosphere as well as the vertical motion of atmosphere is closely related to that of precipitation.展开更多
In this paper, the summer climate of 1991 is taken as a case to study the influence of the transition zone migration on summer drought in North China by using the regional climate model (RegCM2). The results show that...In this paper, the summer climate of 1991 is taken as a case to study the influence of the transition zone migration on summer drought in North China by using the regional climate model (RegCM2). The results show that the transition zone migrates inland, the summer monsoon rainband of 1991 also moves inland. The intensive rainband in the Changjiang River Valley during the Meiyu period moves north. The precipitation in North China increases and the surface air temperature decreases. As a consequence, it results in a good circle between ecosystem and climate. The transition zone migration changes flux transfers between land and atmosphere, and excites secondary circulation or circulation cells around it. All those are closely related with the variation of precipitation.展开更多
文摘In this paper, the summer climate of 1991 in North China is simulated by using the high-resolution regional climate model (RegCM2) and the effects of the grassland desertification on summer drought in the central and the northern parts of North China as well as Mongolia are studied. It shows that the regional climate model essentially catches the characteristics on distribution and seasonal variation of the precipitation that keep good agreement with the observation. The desertification makes precipitation in the central part of North China during its flood period decrease obviously in July. The border of the precipitation or the soil moisture reduction in the desertification region extends about one latitude southeastward and beyond the southeast edge of the desertification. Thus, vegetation in the border region approaches desertification further. However, there appears evident difference of variation of precipitation over the whole desertification region. The grassland desertification greatly changes the transfers of fluxes between land and atmosphere. The secondary circulation or secondary circulation cells in the desertification region are excited and as a result moisture transport is changed. The variation of flux transfers between land and atmosphere as well as the vertical motion of atmosphere is closely related to that of precipitation.
基金This work was supported by the National Key Project "Study on defence technique for agrometeorological disasters".
文摘In this paper, the summer climate of 1991 is taken as a case to study the influence of the transition zone migration on summer drought in North China by using the regional climate model (RegCM2). The results show that the transition zone migrates inland, the summer monsoon rainband of 1991 also moves inland. The intensive rainband in the Changjiang River Valley during the Meiyu period moves north. The precipitation in North China increases and the surface air temperature decreases. As a consequence, it results in a good circle between ecosystem and climate. The transition zone migration changes flux transfers between land and atmosphere, and excites secondary circulation or circulation cells around it. All those are closely related with the variation of precipitation.
