积云团对大气层结影响的模拟研究

文中设计了一个二维完全弹性的积云团数值模式 .模式中考虑了水平均一和时间定常的大尺度抬升速度的影响 .大度抬升速度只对热力学方程和水汽守恒方程有影响 .积云团的启动方式采用冷池和随机扰动相结合的方法 .文中对一个给定温湿层结和大尺度抬升速度情况下 ,就不同扰动结构、水平环境切变、模式区域大小和冷池强度等进行了 1 1个模拟试验 .结果表明 ,在不同扰动结构、是否有水平环境风切变、模式区域不同以及不同云型谱时 ,给定温湿层结和大尺度抬升速度下的积云团活动使得温湿层结向着同一温湿层结调整 .这说明大气由于积云团活动达到准平衡状态 ,这个准平衡状态主要依赖于初始温湿层结和大尺度抬升速度 .这与 Betts积云参数化方案的假设相一致 .

A MODELING STUDY OF THE EFFECTS OF THE CUMULUS ENSEMBLE ON THE ATMOSPHERIC STRATIFICATION

A two dimensional compressible cumulus ensemble numerical model has been developed. In the model a given horizontally uniform and time independent large scale forcing velocity is imposed. The effect of the large scale forcing updraft is included only in the equations for potential temperature and water vapor. Cumulus ensemble was initialized by the combine of a cool pool and random disturbances. Eleven numerical experiments are made under different conditions. Results show that under the condition of the given initial temperature and water vapor sounding and large scale forcing,the cumulus ensemble causes the vertical profile of temperature and water vapor mixing ratio to adjust toward a common profile with different types of initial and random disturbances,whether having horizontal environmental wind shear or not,different model domains and different spectra of cloud sizes. These results show the atmosphere approaches the quasiequilibrium state that mainly depends on the initial sounding and the large scale forcing. All these calculations agree with the idea of Betts' scheme of cumulus parameterization.