中小尺度地形不仅在区域尺度上影响降水和环流形势分布,还会影响季风、西风急流等大尺度的天气系统。新的全球模式分辨率得到明显提高,本研究通过对比分析CAM4高分辨率配置下的模拟结果与高分辨率APHRO降水和ERA-Interim再分析资料,评估高分辨率CAM4对亚洲地区气候系统的模拟性能。结果表明,该模式不仅对亚洲季风-干旱气候系统的大尺度分布特征有良好的模拟能力,还能很好地模拟出季风区和内陆干旱半干旱区年均和季节平均降水的高、低值中心以及水平风场、地表温度和海平面气压的区域差异性特征,尤其是山脉地形附近的降水极值和风场变化。此外,CAM4与气象资料间在不同空间尺度上的空间相关性均很好,其中地表温度的相关系数在0.9以上,降水在亚洲地区超过0.7。
Background, aim, and scope Asian climate is characterized by the Indian monsoon, the East Asian monsoon and inland aridity, which is complex and sensitive to global change. The formation and variation of the climate system are correlated with lots of external forcings, such as solar radiation, landsea distribution and ice sheet. The Tibetan Plateau is also demonstrated to have a vital effect on the Asian monsoons and inland aridity. Besides the large scale plateau, the meso- and small-scale mountains also show great influence. These mountains not only affect the regional precipitation and circulation, but also influence large scale weather systems such as monsoons and westerly jet flow. The climate model CAM4 is with much higher resolution, it can reflect a more realistic topography and resolute those meso- and small-scale mountains to evaluate the climate effect of them. Materials and methods The precipitation data is a daily database from Asian Precipitation-Highly Resolved Observational Data Integration Towards Evaluation of Water Resources of Japan. Its spatial resolution is 0.25°×0.25° from 1951 to 2007. Other meteorological variables such as sea level pressure, horizontal wind and temperature is from ERA-Interim reanalysis data of European Center for Medium-Range Weather Forecasts(ECMWF). The reanalysis data is from 1979 to present with a resolution of 0.75°×0.75°. Besides the meteorological data, the climate model we used to simulate is the CAM4. The CAM4 is the sixth generation of the NCAR atmospheric general climate model. The horizontal resolution is 0.47°×0.63°(latitude×longitude) in the simulation. Results With the apparently increased resolution of global climate model, the modeling result conducted by CAM4 with high resolution is compared with APHRO precipitation and ERA Interim reanalysis data to evaluate whether and in what extent the simulating capability is improved.(1) The CAM4 with high resolution can well simulates the large scale Asian monsoon — aridity climate patter