| Extreme weather and climate change is different by regions,this typical regional characters have effect on the human life more directly,therefore,regional extreme weather and climate change caused widespread concern among the international researchers. Regional climate model becomes an important method undoubtedly due to the low resolution in global climate model. With the development of WRF model, there are some improvements in physics; therefore, making the WRF has the capacity as a regional climate model. This paper focuses to test the capacity of WRF as a regional climate model from some aspects. The analysis of this article was made for the snow and freezing weather occurred in January 2008 in South China more deeply from a point of view of the surface and atmospheric thermodynamic structure and climatic anomaly as well. Second, the incident will be simulated as a typical case, from precipitation, temperature, thermal structure, water vapor and the perspective of the cloud microphysics to examine the capacity of WRF as a regional climate model. The main conclusions are as follows:(1) It was shown that the major area hit by freezing rain was confined in the region of 108°E ~ 113°E and 25°N ~28°N where the mean surface air temperature is below 0℃in January 2008 which is 4-6℃lower than climatology and favorable to form freezing rain. On the other hand, there were continuous transport of warm and moist air from South between 850 hPa and 400 hPa and significant warm air with temperature above 0℃existing in 850-600 hPa, in favor of producing precipitation. Moreover, predominating north wind in 1000– 850 hPa carrying a great deal of cold air kept the surface air temperature below 0℃which made rainfall become freezing while reaching the surface. In terms of annual climate anomaly, upper southerly and lower northerly were much stronger than the averages, and upper air was far warmer and lower air far colder than normal. These anomalous conditions in January 2008 were very favorable to occurrence of the hazard of the snow and freeing rain that is historically rare in South China.(2) The snow and ice storms in 2008 as a typical event was simulated, when the WRF model select Morrison microphysics and Kain-Fritsch scheme (Test 1), the model can reflect the good ability in the region of 108°E ~ 113°E and 25°N ~28°N:It can give more accurate simulation results in the south of the Yangtze position and precipitation, just more north and west than the actual position, precipitation is more. The regional simulation of the low temperature range is smaller than the actual distribution. The same model can better simulate the surface temperature of approximately latitude - time distribution. From the simulation of thermal structure anomalies situation, the simulated inversion layer is more north. To water vapor, the model and the actual results are relatively similar, upper southerly and lower northerly were much stronger than the reality.(3) In order to test the capacity of WRF as a regional model by choosing the different microphysical scheme and cumulus scheme, test 2 is choosing Kain-Fritsch and Ferrier, test 3 is New Grell scheme and Morrison combination, test 4 is New Grell scheme and Ferrier. The result indicates: test 1 is better than others. With the results of four groups, evaluate the impact on precipitation intensity, the results show: the rainfall in large scale is similar with the actual situation; however, the little precipitation is very different with the reality.(4) Cloudsat satellite can supply a large number of cloud internal structure information, testing the simulation capacity through the cloud microphysical structure about the center region 108°E -113°E and 25°N -28°N, the results show: the liquid water content in WRF model is wider than satellite data, however, the simulation of ice water content is better.(5) Select a satellite orbit through Hunan province in January 28. Make a contrast between the simulation results and actual cloudsat data, the results indicate: WRF model can simulate the solid water and liquid water content of the spatial distribution and height distribution, in addition, more importantly, WRF model make a good simulation about the structure and melting temperature inversion layer. Therefore, WRF model in the cloud microphysical structure reflects a very good simulation capability.
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