本文利用多种观测资料、再分析资料及WRF(Weather Research and Forecasting Model)模式,对2017年12月23—25日发生于中国东部沿海入海加强的一个强暴发性气旋进行了研究,并探讨了海陆地形和热力差异对暴发性气旋发展的影响。该暴发性...本文利用多种观测资料、再分析资料及WRF(Weather Research and Forecasting Model)模式,对2017年12月23—25日发生于中国东部沿海入海加强的一个强暴发性气旋进行了研究,并探讨了海陆地形和热力差异对暴发性气旋发展的影响。该暴发性气旋的最大加深率为1.7Bergerons,其下垫面经历的“海洋-陆地-海洋”的复杂变化对其发展过程产生了显著影响。该气旋登陆朝鲜半岛时,气温降低,水平风速减小,上升运动增强,降水增加;而离开朝鲜半岛后,气温升高,上升运动减弱,降水减少。海陆差异的敏感性试验表明,陆地下垫面对气旋发展的动力作用主要是通过地面摩擦和地形抬升来实现的,而海洋对气旋发展的作用则主要表现在海表面热量和水汽传输方面。当气旋经过陆地时,由于陆地表面摩擦较大,气旋中心近地面水平风速减小。而较高的地形则会产生较强的上升运动,形成较强降水,促进类CISK(Conditional Instability of Second Kind)机制,使气旋加强。当气旋位于海面上时,冬季海面温度高于陆地,海洋向气旋输送更多的热量和水汽,从而更有利于气旋的发展。展开更多
In this paper, the numerical experiments on the issue of spin-up time for seasonal-scale regional climate modeling were conducted with the newly Regional Climate Model （RegCM3）, in the case of the abnormal climate e...In this paper, the numerical experiments on the issue of spin-up time for seasonal-scale regional climate modeling were conducted with the newly Regional Climate Model （RegCM3）, in the case of the abnormal climate event during the summer of 1998 in China. To test the effect of spin-up time on the regional climate simulation results for such abnormal climate event, a total of 11 experiments were performed with different spin-up time from 10 days to 6 months, respectively. The simulation results show that, for the meteorological variables in the atmosphere, the model would be running in “climate mode” after 4-8-day spin-up time, then, it is independent of the spin-up time basically, and the simulation errors are mainly caused by the model＇ s failure in describing the atmospheric processes over the model domain. This verifies again that the regional climate modeling is indeed a lateral boundary condition problem as demonstrated by earlier research work. The simulated mean precipitation rate over each subregion is not sensitive to the spin-up time, but the precipitation scenario is somewhat different for the experiment with different spin-up time, which shows that there exists the uncertainty in the simulation to precipitation scenario, and such a uncertainty exhibits more over the areas where heavy rainfall happened. Generally, for monthly-scale precipitation simulation, a soin-uo time of 1 month is enough, whereas a spin-up time of 2 months is better for seasonal-scale one. Furthermore, the relationship between the precipitation simulation error and the advancement/withdrawal of East Asian summer monsoon was analyzed. It is found that the variability of correlation coefficient for precipitation is more significant over the areas where the summer monsoon is predominant. Therefore, the model＇s capability in reproducing precipitation features is related to the heavy rainfall processes associated with the advancement/withdrawal of East Asian summer monsoon, which suggests that it is necessary to develop a more reliable parameterization scheme to capture the convective precipitation of heavy rainfall pro- cesses associated with the activities of East Asian summer monsoon, so as to improve the climate modeling over China.展开更多
文摘本文利用多种观测资料、再分析资料及WRF(Weather Research and Forecasting Model)模式,对2017年12月23—25日发生于中国东部沿海入海加强的一个强暴发性气旋进行了研究,并探讨了海陆地形和热力差异对暴发性气旋发展的影响。该暴发性气旋的最大加深率为1.7Bergerons,其下垫面经历的“海洋-陆地-海洋”的复杂变化对其发展过程产生了显著影响。该气旋登陆朝鲜半岛时,气温降低,水平风速减小,上升运动增强,降水增加;而离开朝鲜半岛后,气温升高,上升运动减弱,降水减少。海陆差异的敏感性试验表明,陆地下垫面对气旋发展的动力作用主要是通过地面摩擦和地形抬升来实现的,而海洋对气旋发展的作用则主要表现在海表面热量和水汽传输方面。当气旋经过陆地时,由于陆地表面摩擦较大,气旋中心近地面水平风速减小。而较高的地形则会产生较强的上升运动,形成较强降水,促进类CISK(Conditional Instability of Second Kind)机制,使气旋加强。当气旋位于海面上时,冬季海面温度高于陆地,海洋向气旋输送更多的热量和水汽,从而更有利于气旋的发展。
基金Supported jointly by the National Natural Science Foundation of China under Grant Nos.40675065,40333026the Program of Jiangsu Key Laboratory of Meteorological Disaster (KJS0605).
文摘In this paper, the numerical experiments on the issue of spin-up time for seasonal-scale regional climate modeling were conducted with the newly Regional Climate Model （RegCM3）, in the case of the abnormal climate event during the summer of 1998 in China. To test the effect of spin-up time on the regional climate simulation results for such abnormal climate event, a total of 11 experiments were performed with different spin-up time from 10 days to 6 months, respectively. The simulation results show that, for the meteorological variables in the atmosphere, the model would be running in “climate mode” after 4-8-day spin-up time, then, it is independent of the spin-up time basically, and the simulation errors are mainly caused by the model＇ s failure in describing the atmospheric processes over the model domain. This verifies again that the regional climate modeling is indeed a lateral boundary condition problem as demonstrated by earlier research work. The simulated mean precipitation rate over each subregion is not sensitive to the spin-up time, but the precipitation scenario is somewhat different for the experiment with different spin-up time, which shows that there exists the uncertainty in the simulation to precipitation scenario, and such a uncertainty exhibits more over the areas where heavy rainfall happened. Generally, for monthly-scale precipitation simulation, a soin-uo time of 1 month is enough, whereas a spin-up time of 2 months is better for seasonal-scale one. Furthermore, the relationship between the precipitation simulation error and the advancement/withdrawal of East Asian summer monsoon was analyzed. It is found that the variability of correlation coefficient for precipitation is more significant over the areas where the summer monsoon is predominant. Therefore, the model＇s capability in reproducing precipitation features is related to the heavy rainfall processes associated with the advancement/withdrawal of East Asian summer monsoon, which suggests that it is necessary to develop a more reliable parameterization scheme to capture the convective precipitation of heavy rainfall pro- cesses associated with the activities of East Asian summer monsoon, so as to improve the climate modeling over China.
