中文摘要：

对法国动力气象实验室发展的变网格全球大气环流模式LMDZ4在东亚地区的模拟性能进行评估。LMDZ4作为海气耦合模式IPSL-CM5A的大气模块,本文局地格点加密区域位于东亚上空,加密区外使用ERA-interim再分析资料进行驱动,积分时段为1979—2009年。通过对模式在东亚东部区域夏季气候的模拟能力评估,发现模式整体上能够真实地模拟出南亚高压、西风急流、西太副高、水汽输送以及夏季风等环流系统的气候平均态,地面雨带和气温的分布及极值中心都得到较好再现。同时模式仍显现一定的偏差,具体表现为,华南沿海的模拟偏冷偏湿,江淮流域偏暖偏干,而东北地区则偏暖偏湿,导致这种地面要素场偏差的原因来自于中上层环流场的系统性模拟偏差。例如,高层南亚高压、西风急流模拟偏弱,而印度季风和来自印度洋的水汽输送偏强,导致华南沿海降水偏多。西太平洋副高偏东偏弱,低纬东风带强度偏弱,西太平洋区域比湿偏小,使得东南风带来的水汽无法到达江淮流域。上述偏差的产生可能由于LMDZ4模式中的云参数化方案尚存在不足之处,使得云量的模拟偏少,并且该版本模式的垂直分辨率不足,限制了它对高层环流系统的模拟能力,增加了模式的系统误差。

英文摘要：

LMDZ4, a variable-resolution global atmospheric general circulation model,is assessed against observed data in Southeast Asia before its further utilization in climate change downscaling studies.The model is developed in the Laboratoire de Meteorologie Dynamique in Paris, as the atmospheric component of the ocean--atmosphere coupled system IPSL-CM5A.In order to investigate the ability of LMDZ4 in simulating East Asian summer precipitation, temperature and circulation, this paper analyzes the causes of simulation deviation and some of the uncertainties in this model.The study is expected to lay a foundation for further forecasting of future climate changes.In this study, LMDZ4 has its domain centered over Southeast Asia[ domain center at （30°N, 110°E） ;cover-age：（5-55°N, 85-135°E）], and is driven by ERA-Interim reanalysis data from 1979 to 2009. It is actually used as a traditional limited-area model with the whole globe as the buffer zone that receives the ERA-Interim data.The nudged variables include zonal wind,meridional wind,temperature and specific humidity,with a time interval of 6 h.There are 121×120（latitudexlongitude）grids and 19 layers in the vertical direction.The spatial resolution inside the domain is approximately 0.6°×0.6°.The driving forcing is added through a relaxation procedure. We impose a long（ 10 days,but not infinite,to be comparable with other simulations using this historical set-up） relaxation time scale inside the domain,while the relaxation time scale outside the domain is 1.5 h.The use of two distinct relaxation time scales inside and outside the domain enables the model to run almost freely inside the domain, whereas it completely follows the forcing outside the domain. For the purpose of model assessment, daily temperature and rainfall at a few meteorological stations in China are used.These two datasets are available with a resolution of 0.5°×0.5°. Results show that the mean state of the major atmospheric general circulation systems can be simulated well