青藏高原上空UTLS区域一次地形重力波过程中的物质上传  

Upward transport of air mass during ageneration of orographic waves in the UTLS over the Tibetan Plateau

作　　者：魏栋[1,2] 田文寿[1] 陈泽宇[3] 张健恺[1] 许平平[1] 黄倩[1] 韩元元[1] 张杰[1] 

机构地区：[1]兰州大学大气科学学院半干旱气候变化教育部重点实验室,兰州730000 [2]兰州中心气象台,兰州730020 [3]中国科学院大气物理研究所中层大气与全球环境探测重点实验室,北京100029

出　　处：《地球物理学报》2016年第3期791-802,共12页Chinese Journal of Geophysics

基　　金：国家杰出青年科学基金项目(41225018);中国科学院重点部署项目(KZZD-EW-01-1);国家自然科学基金面上项目(41175042;41275006)资助

摘　　要：利用美国航空航天局MERRA(Modern-Era Retrospective Analysis for Research and Applications)再分析资料和MODIS(Moderate-Resolution Imaging Spectroradiometer)卫星资料以及欧洲气象中心ECMWF-Interim(European Centre for Medium-Range Weather Forecasts)再分析资料,分析了发生于青藏高原北侧上空的一次地形重力波事件,并使用中尺度预报模式WRF-ARW.V3.0(Weather Research and Forecasting model,V3.0)对其进行了数值模拟.在此基础上,诊断分析了此次地形重力波在UTLS(Upper Troposphere and Lower Stratosphere)区域造成的物质和能量垂直传输特征.分析结果表明这一中尺度地形重力波信号的水平波长约为600km,与地形扰动水平尺度接近,重力波在对流层中传播的垂直波长约为3km,在垂直方向上随着高度的增加呈现出由东向西倾斜的结构特征.此次地形重力波上传进入平流层并在150hPa附近破碎,波破碎后动量通量在短时间内发生了强烈的衰减,重力波携带的能量在破碎高度附近释放.重力波破碎的同时垂直方向湍流混合变得异常强烈,湍流交换系数可在短时间内增加到背景值的8倍以上,剧烈湍流混合过程导致了对流层上层的空气进入平流层,使下平流层空气出现了位势涡度和臭氧的低值区,在浮力频率的垂直剖面中也可以看到由于地形重力波过程造成的平流层下层浮力频率异常低值区.This work examined the characteristics of an orographic gravity wave event during0∶00～6∶00UTC on 1 May 2008 and its impacts on stratosphere and troposphere exchange,using NASA MERRA（Modern-Era Retrospective Analysis for Research and Applications）and European Centre for Medium-Range Weather Forecasts（ECMWF）Interim reanalysis data and Moderate Resolution Imaging Spectroradiometer（MODIS）data,in combination with the Weather Research and Forecasting model（WRF）. The results show that the horizontal wavelength is about 600 km throughout the troposphere and stratosphere,close to the terrain width,and the vertical wavelength is about 3km in the troposphere.The wave structure shows a westward tilt with height.Orographic waves propagate upward into the stratosphere and break up near 150 hPa,leading to a strong attenuation of momentum flux and the release of energy into basic flows.Meanwhile,vertical turbulent mixing is extremely increased and turbulent exchange coefficient enhances more than eight times during a short period（within 1hour）.Large turbulent mixing process causes air transport from the troposphere to the stratosphere,corresponding to the low value of ozone,potential vorticity and buoyancy frequency in the lower stratosphere.

关 键 词：地形重力波 上对流层下平流层 平流层对流层交换 WRF模式 

分 类 号：P432[天文地球—大气科学及气象学]