切比雪夫多项式在模式地形平滑中的应用研究  

Research on Application of Chebyshev Polynomial Filtering Method in Smooth Topography of GRAPES Model

作　　者：屠妮妮[1] 陈静[2] 何光碧[1] 

机构地区：[1]中国气象局成都高原气象研究所,四川成都610072 [2]中国气象局国家气象中心,北京100081

出　　处：《高原气象》2012年第1期47-56,共10页Plateau Meteorology

基　　金：中国气象局数值模拟创新基地科研业务开放课题"精细化GRAPES模式高原地形优化方案研究";中国气象局成都高原气象开放试验室基金课题(BROP200711);国家自然科学基金项目(40675061);四川省气象局科研课题(2007-30)共同资助

摘　　要：利用切比雪夫多项式展开滤波方法获得较为平滑的模式地形,并对2008年7月20～22日四川省一次大暴雨过程进行了数值模拟,通过地形敏感性试验讨论了地形对暴雨的影响作用以及平滑地形对GRAPES模式的适用性。结果表明,切比雪夫多项式展开滤波方案选取高阶截断项数,促使模式地形更为平滑,地形高度变化使得垂直速度发生变化,进而引起降水变化,上升运动强度增强(或减弱)引起该区域内雨强增强(或减弱)。2008年7月2～28日连续26天的试验表明,切比雪夫多项式展开滤波方案对GRAPES模式中的小雨和中雨预报有改善作用,对大雨和暴雨改善较小。总体来看,切比雪夫多项式在地形平滑中对降水预报有正的效果。Using the Chebyshev polynomial filtering method to obtain relatively smooth topography which was used in GRAPES model,a heavy rainstorm occurred in Sichuan Province during 20～22 July 2008 was simulated to discuss the impact of topography on precipitation according to topography sensitive test,as well as the applicability of smooth topography to the GRAPES model.The results show that Chebyshev polynomial filtering method through reducing the height of mountain and uplifting the height of depressions to achieve a smooth terrain,change of terrain height makes the vertical velocity change,thus causing changes in precipitation,increase in ascend exercise intensity is increased（or decreased） in the region caused by the rain intensity is enhanced（or weakened）.The results of 26-day experiment during 2～28 July 2008 show that,Chebyshev polynomial filtering method has improved effect on light rain and moderate rain of GRAPES model,has smaller improved effect on heavy rainstorm and rainstorm.In generally,the Chebyshev scheme has the effect to the precipitation forecast.

关 键 词：切比雪夫多项式 地形平滑 大暴雨 数值模拟 

分 类 号：P435[天文地球—大气科学及气象学]