基于一个不同网格相互嵌套的陆气耦合模式的气候模拟研究

摘要

将一个大气植被相互作用模式(AVIM)与大气所LASG的R 15九层大气环流模式GOALS相耦合,用来模拟多年平均的全球气候状况.AVIM是一个陆地表面陆面和生理过程相互反馈的模型.作为陆气耦合的第一步,暂不考虑AVIM中的生理过程,而首先将其物理过程[相当于通常的SVAT(土壤-植被-大气-传输方案)模型]与大气所LASG的九层大气环流模式耦合起来,其中海洋模式部分不参与积分,海面温度是多年平均的气候值.考虑到GCM的分辨率较低(7.5°×4.5°)而植被分布必须有较高的分辨率(1.5°×1.5°),采取了大气与地表面粗细网格的嵌套耦合.模式积分15年,取最后10年的平均值作分析.将模拟的气候要素场与观测值和NCEP再分析资料作了比较,气候模拟结果反映了全球环流与温湿场的主要特征,特别是降水和地面气温的模拟效果较好.这为今后气候模式与生物圈的耦合奠定了一个良好的基础.%An atmosphere-vegetation interaction model (AVIM) has been coupled with a nine-layer General Circulation Model (GCM) of Institute of Atmospheic Physics / State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics (IAP/LASG), which is rhomboidally truncated at zonal wave number 15, to simulate global climatic mean states. AVIM is a model having inter-feedback between land surface processes and eco-physiological processes on land. As the first step to couple land with atmosphere completely, the physiological processes are fixed and only the physical part (generally named the SVAT (soil-vegetation-atmosphere-transfer scheme) model) of AVIM is nested into IAP/LASG L9R15 GCM. The ocean part of GCM is prescribed and its monthly sea surface temperature (SST) is the climatic mean value. With respect to the low resolution of GCM, i.e., each grid cell having longitude 7.5° and latitude 4.5°, the vegetation is given a high resolution of 1.5° by 1.5° to nest and couple the fine grid cells of land with the coarse grid cells of atmosphere. The coupling model has been integrated for 15years and its last ten-year mean of outputs was chosen for analysis.Compared with observed data and NCEP reanalysis, the coupled model simulates the main characteristics of global atmospheric circulation and the fields of temperature and moisture. In particular, the simulated precipitation and surface air temperature have sound results. The work creates a solid base on coupling climate models with the biosphere.