RegCM4中陆面过程参数化方案对东亚区域气候模拟的影响

The effects of the land-surface process parameterization of the RegCM4 on climate simulation in East Asia

中文关键词:  RegCM4， 陆面过程， 气候模拟， 敏感性分析

英文关键词:RegCM4,Land surface process, Climate simulation, Analysis of sensibility

中文摘要:

      利用区域气候模式RegCM4.0分别选取其陆面参数化方案CLM3.5与BATS1e，针对东亚地区进行约44 a（1957—2001年）的模拟试验（分别取名为R-CLM与R-BATS），以研究陆面过程参数化方案对区域气候模拟的影响。结果表明，R-CLM地表气温比R-BATS平均高3.6℃，均方根误差比R-BATS约减少44%，其中，以中国华南、西北等地区的偏高改进最为明显；降水平均减少0.17 mm/d，均方根误差约减少6.9%，其中，在中国华南、东北等东部地区误差减少最多；表层10 cm土壤湿度平均增加0.008 m 3/m 3，并在中国东北等中高纬度地区偏大最为明显。分析表明，R-CLM模拟的土壤湿度在中高纬度地区比R-BATS偏高是由于其蒸散与地表径流较少使得陆地水储量相对较高所致，因而该地区的产流机制仍需改进以改善其土壤湿度模拟；R-CLM的地表气温模拟普遍较高主要是由于其陆表吸收辐射量模拟较高潜热通量模拟较弱所致；另外，R-CLM中较弱的蒸散与较高的地表气温引起了大气环流场的改变，导致R-CLM在模拟区尤其是中国东部地区模拟的垂向及水平水汽输送较弱，大气可降水量较少，因而在中国华南、东北等大部分地区降水相对偏少，并在一定程度上增加了到达地表的辐射量，进而影响其地表气温模拟。

英文摘要:

      Two 44-year numerical simulations in East Asia by the regional climate model RegCM4.0 using its land-surface schemes， CLM3.5 and BATS1e were conducted to investigate the effects of land surface process parameterization schemes in a regional climate model on the regional climatic simulation. The two simulations were named as R-BATS and R-CLM，corresponding to CLM3.5 and BATS1e, respectively. The results revealed that the simulated surface air temperature from R CLM was 3.6℃ higher in average, with its decreased root mean square error for 44% compared to that of R-BATS and higher differences appeared in South and Northwest China；the simulated precipitation by R-CLM was 0.17 mm/d less，with its root mean square error decreased for 6.9% and higher differences appeared in South and Northeast China；and the simulated 10 cm soil moisture by R-CLM was 0.008 m3/m3 wetter and higher differences appeared in the regions of the middle and high latitudes. Further analysis revealed that less evapotranspiration and runoff simulated by R-CLM induced its higher soil moisture in the regions of middle and high latitudes，suggesting that further improvement in runoff generation mechanism overthere is needed. More absorbed solar flux and weaker latent flux also induced the higher surface air temperature in R-CLM. Besides， weaker evapotranspiration and higher surface temperatures also induced changes in the general circulation，causing weaker water vapor transport in vertical and horizontal directions and less atmospheric precipitable water. As a result， less precipitation was simulated in most areas including South and Northeast China， which further affected the surface air temperature in some extent owing to more solar flux into land surface.