AGCM中云的不均匀性作用的初步研究

The Study of the Effect of Cloud Inhomogeneity in AGCM

利用ISCCP的云不均匀性资料,探讨了云不均匀性在AGCM中的作用,分别考查了不均匀云光学厚度的贡献、单次散射反照率和不对称因子的贡献,以及3个因子的总贡献。研究表明,考虑云不均匀性效应后,AGCM模拟的气候场有着较为明显的变化。由于不均匀云光学厚度对短波辐射场的贡献与不均匀云单次散射反照率和不对称因子这两个因子对短波辐射场的作用基本上是相反的,从而造成同时考虑3个因子作用时,云的不均匀性效应对辐射场的直接作用很小,但可通过云水场的改变来间接影响辐射场。研究清楚地显示了云-辐射相互作用的复杂性,云的全面正确处理对模式模拟能力的提高非常重要。

By using the mesoscale cloud inhomogeneity data obtained from ISCCP, the effects of cloud inhomogeneity in lAP AGCM have been investigated. Numerical simulation results have shown that cloud inhomogeneity has obvious influence on the simulated climates, such as precipitation, ground surface air temperature, and sea level pressure. The effect of optical depth of inhomogeneous clouds on solar radiation fields is shown to be opposite to those of the single-scattering albedo and asymmetry factor of inhomogeneous clouds, which has led to a small overall direct influence on radiation field. In AGCM, cloud inhomogeneity is mainly through the cloud water field to indirect influence the radiation field. Our research has clearly shown the importance of cloud-radiation interaction, and the importance of cloud parameterization for the improvement of the performance of global climate models.