应用谱逼近方法模拟2008年初南方持续性降水过程及其水汽通道周期特征分析  

Simulation of Continuous Rainfall over South China in Early 2008 with the Spectral Nudging Method and the Periodicity Characteristics of the Water Vapor Channel

作　　者：王淑莉[1] 徐祥德[1] 康红文[1] 张胜军[1] 张夕迪 

机构地区：[1]中国气象科学研究院灾害天气国家重点实验室,北京100081 [2]国家气象中心,北京100081

出　　处：《大气科学》2016年第3期476-488,共13页Chinese Journal of Atmospheric Sciences

基　　金：国家科技支撑计划项目2012BAK10B04;国家自然科学基金项目41130960~~

摘　　要：本文利用谱逼近方法,对2008年初发生在我国南方的大范围持续性降水过程进行了对比试验,结果发现使用谱逼近方法的试验模拟所得的雨带空间分布和降水强度明显优于没有使用谱逼近方法的试验。对于低层受槽线、风切变线等频繁影响的区域,使用谱逼近方法的试验得到的经向风场具有2~4天的显著周期特征,与实况较为一致,即该方法能够提高模式对经向风场的模拟能力。综合分析水汽输送通道、模拟区域位置以及水汽通道超前高相关区的周期特征可知：谱逼近方法可能把中南半岛东部区域这一超前高相关区的经向水汽输送信息引入模式,从而改善了模式对降水区水汽收支周期的模拟能力,这可能是该方法能够改善降水模拟的重要原因之一。另外,对于谱逼近方法没有直接作用的模式变量,经过模式内部各变量之间的相互调整,其在谱逼近试验中的统计结果也有不同程度的提高。本文研究结果表明,谱逼近试验通过引入外源性的周期特征因素项,调整了模式与大尺度驱动场之间的协调关系,进而能够提高两周内模式模拟水平。此方法可能会在模式数值预报中具有一定的实际使用价值。The spectral nudging（SP） method is used in simulating continuous precipitation processes that occurred over South China in early 2008. The results show that the spatial distribution and intensity of precipitation in the SP experiment is obviously better than that without use of this method（NOSP）. For the area affected frequently by troughs or wind shear lines in lower layers, a 2–4-day oscillation period of meridional wind is found in the SP experiment, which is consistent with observations. This means that the SP method may enhance the simulation ability of the meridional wind field. Based on a comprehensive analysis of the water vapor transport pathway, the model domains and periodicity features of high-correlation regions in advance of the water vapor channel, we find that the SP method can introduce meridional vapor transport information over the eastern Indo-China Peninsula into the model, improving the simulation ability of the cycle of the water vapor budget in the precipitation area. This could be an important reason why the SP method improves the rainfall simulation in the SP experiment. Furthermore, the variables indirectly affected by the SP method are statistically improved by means of the interaction with other variables in the SP experiment. Above all, the exogenous cycle characteristic factors introduced by the SP method, which adjust the coordination between modeling and large-scale forcing fields, could improve simulation results within a forecast time of two weeks. This method has the potential to be of practical value in numerical prediction.

关 键 词：降水模拟 谱逼近 水汽输送 

分 类 号：P456[天文地球—大气科学及气象学]