青藏高原东侧一次低涡暴雨过程地形影响的数值试验
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摘要
由于模式地形与实际地形存在不同程度偏差,而地形对降水有着重要作用,利用WRFV3.1模式,引入气象站海拔改变模式局地地形方法,针对2008年7月20-22日四川盆地一次强降水过程,分析了地形对数值模式预报效果的影响。结果表明,模式中引入更真实地形使得降水强度增大、强降水中心位置和发生时间有所改善,对流层中低层上升运动和气旋切变显著增加,低涡位置有所改善,由此带来更强的降水和落区改善;改变单点地形高度后,其上空气象要素较周边地区都有所变化,随着模式地形高度的改变其幅度不断增加,气象要素变化也更为显著;引入更真实地形使得降水中心增湿、增温和降低高度特征非常明显,气象要素的变化有利于地形改变后低值系统的加强和降水强度的增强。单点地形高度改变可引起初始时刻局地气象要素的微小偏差,但随着积分时间增长,偏差则进一步加大。在保证模式积分稳定的前提下,提出了通过一些关键点引入实际地形高度,从而改进模式的预报效果,特别是降水预报效果的一种地形处理思路。
Because of the terrain model and real terrain have different degree of deviations,and the terrain on precipitation plays an important role.Using WRFV3.1model,the influence of topography on the numerical model forecast effect was analyzed as to an heavy precipitation in Sichuan basin on 20-22July 2008through the meteorological station elevation changing the model grid point terrain height method and introduction of the more realistic terrain model.The results show that the more real terrain in model is introduce to increase the intensity of precipitation,location and occurring time of severe precipitation center are improved;the ascending motion and cyclonic shear in middle and lower troposphere increased significantly,the vortex position is improved,which result in the improvements of severe precipitation location and occurring time.The changing of single point of terrain height cause the above meteorological elements have changed than the surrounding areas.The variation of meteorological element is more remarkable with the increasing of terrain height change in model.The more real terrain makes the characteristics of the humidity increasing,height decreasing and temperature increasing are more significant.Variations of meteorological elements are in favor of low value system strengthening and precipitation intensity increasing after the topography change.The change of single point of terrain height cause a slight deviation of initial local meteorological elements,the deviation further increases with integration time.The regional pattern,in order to ensure the integral stability of the model,the real terrain height is introduced through some key points to improve the prediction effect,especially a terrain processing idea of precipitation prediction.
Because of the terrain model and real terrain have different degree of deviations,and the terrain on precipitation plays an important role.Using WRFV3.1model,the influence of topography on the numerical model forecast effect was analyzed as to an heavy precipitation in Sichuan basin on 20-22July 2008through the meteorological station elevation changing the model grid point terrain height method and introduction of the more realistic terrain model.The results show that the more real terrain in model is introduce to increase the intensity of precipitation,location and occurring time of severe precipitation center are improved;the ascending motion and cyclonic shear in middle and lower troposphere increased significantly,the vortex position is improved,which result in the improvements of severe precipitation location and occurring time.The changing of single point of terrain height cause the above meteorological elements have changed than the surrounding areas.The variation of meteorological element is more remarkable with the increasing of terrain height change in model.The more real terrain makes the characteristics of the humidity increasing,height decreasing and temperature increasing are more significant.Variations of meteorological elements are in favor of low value system strengthening and precipitation intensity increasing after the topography change.The change of single point of terrain height cause a slight deviation of initial local meteorological elements,the deviation further increases with integration time.The regional pattern,in order to ensure the integral stability of the model,the real terrain height is introduced through some key points to improve the prediction effect,especially a terrain processing idea of precipitation prediction.
引文
[1]丁一汇.高等天气学[M].北京:气象出版社,2005:330.
[2]陶诗言等编著.中国之暴雨[M].北京:科学出版社,1980:13.
[3]赵玉春,许小峰,崔春光.中尺度地形对梅雨锋暴雨影响的个例研究[J].高原气象,2012,31(5):1268-1282.
[4]刘裕禄,黄勇.黄山山脉地形对暴雨降水增幅条件研究[J].高原气象,2013,32(2):608-615,doi:10.7522/j.issn.1000-0534.2012.00059.
[5]郁淑华,滕家谟,何光碧.高原地形对四川盆地西部突发性暴雨影响的数值试验[J].大气科学,1998,22(3):379-383.
[6]何光碧.高原东侧陡峭地形对一次盆地中尺度涡旋及暴雨的数值试验[J].高原气象,2006,25(3):430-441.
[7]尹宜舟,沈新勇,李焕连.“07.7”淮河流域梅雨锋暴雨的地形敏感性试验[J].高原气象,2009,28(5):1085-1094.
[8]姚昊,潘晓滨,臧增亮.一次鄂西地区暴雨过程中地形敏感性试验研究[J].气象与环境学报,2008,24(5):61-66.
[9]高学杰,徐影,赵宗慈,等.数值模式不同分辨率和地形对东亚降水模拟影响的试验[J].大气科学,2006,30(2):186-192.
[10]董海萍,赵思雄,曾庆存.低纬高原地形对强降水过程影响的数值试验研究[J].气候与环境研究,2007,12(3):381-396.
[11]廖菲,洪延超,郑国光.地形对降水的影响研究[J].气象科技,2007,35(3):309-316.
[12]高坤,翟国庆,俞樟孝,等.华东中尺度地形对浙北暴雨影响的模拟研究[J].气象学报,1994,52(2):157-164.
[13]毕宝贵,刘月巍,李泽椿.地表热通量对陕南强降水的影响[J].地理研究,2005,24(5):681-691.
[14]潘在桃.中尺度数值模式中初始场和地形的不同处理对降水预报的影响及相对比较[J].气象学报,1990,48(4):491-499.
[15]刘还珠.青藏高原的不同地形方案对天气系统影响的数值试验[J].大气科学,1988,12(2):162-167.
[16]程麟生,郭英华.初始条件和大地形对西南涡演变的中尺度模拟影响[J].兰州大学学报:自然科学版,1990,26(4):140-147.
[17]钱永甫,董梁.包络地形对气候模拟特征的影响[J].高原气象,1995,14(2):129-140.
[18]刘一,陈德辉,胡江林,等.GRAPES中尺度模式地形有效尺度影响的理想数值试验研究[J].热带气象学报,2011,27(1):53-62.
[19]王光辉,陈峰峰,沈学顺,等.数值模式中地形滤波处理及水平扩散对降雨预报的影响[J].地球物理学报,2008,51(6):1642-1650.
[20]何光碧,高文良,屠妮妮.两次高原低涡东移特征及发展机制动力诊断[J].气象学报,2009,67(4):599-612.
[21]屠妮妮,陈静,何光碧.切比雪夫多项式展开滤波方案在模式地形的适用性研究[J].高原气象,2012,31(1):47-56.
[22]李强,李永华,周锁铨,等.基于WRF模式的三峡地区局地下垫面效应的数值试验[J].高原气象,2011,30(1):83-93.
[23]廖菲,胡娅敏,洪延超.地形动力作用对华北暴雨和云系影响的数值研究[J].高原气象,2009,28(1):115-126.
[24]赵桂香.一次阻高背景下地形对晋南特大暴雨的作用分析[J].高原气象,2009,28(4):897-905.
[25]姜勇强,王元.地形对1998年7月鄂东特大暴雨鞍型场的影响[J].高原气象,2010,29(2):297-308.
[2]陶诗言等编著.中国之暴雨[M].北京:科学出版社,1980:13.
[3]赵玉春,许小峰,崔春光.中尺度地形对梅雨锋暴雨影响的个例研究[J].高原气象,2012,31(5):1268-1282.
[4]刘裕禄,黄勇.黄山山脉地形对暴雨降水增幅条件研究[J].高原气象,2013,32(2):608-615,doi:10.7522/j.issn.1000-0534.2012.00059.
[5]郁淑华,滕家谟,何光碧.高原地形对四川盆地西部突发性暴雨影响的数值试验[J].大气科学,1998,22(3):379-383.
[6]何光碧.高原东侧陡峭地形对一次盆地中尺度涡旋及暴雨的数值试验[J].高原气象,2006,25(3):430-441.
[7]尹宜舟,沈新勇,李焕连.“07.7”淮河流域梅雨锋暴雨的地形敏感性试验[J].高原气象,2009,28(5):1085-1094.
[8]姚昊,潘晓滨,臧增亮.一次鄂西地区暴雨过程中地形敏感性试验研究[J].气象与环境学报,2008,24(5):61-66.
[9]高学杰,徐影,赵宗慈,等.数值模式不同分辨率和地形对东亚降水模拟影响的试验[J].大气科学,2006,30(2):186-192.
[10]董海萍,赵思雄,曾庆存.低纬高原地形对强降水过程影响的数值试验研究[J].气候与环境研究,2007,12(3):381-396.
[11]廖菲,洪延超,郑国光.地形对降水的影响研究[J].气象科技,2007,35(3):309-316.
[12]高坤,翟国庆,俞樟孝,等.华东中尺度地形对浙北暴雨影响的模拟研究[J].气象学报,1994,52(2):157-164.
[13]毕宝贵,刘月巍,李泽椿.地表热通量对陕南强降水的影响[J].地理研究,2005,24(5):681-691.
[14]潘在桃.中尺度数值模式中初始场和地形的不同处理对降水预报的影响及相对比较[J].气象学报,1990,48(4):491-499.
[15]刘还珠.青藏高原的不同地形方案对天气系统影响的数值试验[J].大气科学,1988,12(2):162-167.
[16]程麟生,郭英华.初始条件和大地形对西南涡演变的中尺度模拟影响[J].兰州大学学报:自然科学版,1990,26(4):140-147.
[17]钱永甫,董梁.包络地形对气候模拟特征的影响[J].高原气象,1995,14(2):129-140.
[18]刘一,陈德辉,胡江林,等.GRAPES中尺度模式地形有效尺度影响的理想数值试验研究[J].热带气象学报,2011,27(1):53-62.
[19]王光辉,陈峰峰,沈学顺,等.数值模式中地形滤波处理及水平扩散对降雨预报的影响[J].地球物理学报,2008,51(6):1642-1650.
[20]何光碧,高文良,屠妮妮.两次高原低涡东移特征及发展机制动力诊断[J].气象学报,2009,67(4):599-612.
[21]屠妮妮,陈静,何光碧.切比雪夫多项式展开滤波方案在模式地形的适用性研究[J].高原气象,2012,31(1):47-56.
[22]李强,李永华,周锁铨,等.基于WRF模式的三峡地区局地下垫面效应的数值试验[J].高原气象,2011,30(1):83-93.
[23]廖菲,胡娅敏,洪延超.地形动力作用对华北暴雨和云系影响的数值研究[J].高原气象,2009,28(1):115-126.
[24]赵桂香.一次阻高背景下地形对晋南特大暴雨的作用分析[J].高原气象,2009,28(4):897-905.
[25]姜勇强,王元.地形对1998年7月鄂东特大暴雨鞍型场的影响[J].高原气象,2010,29(2):297-308.