王宇虹,徐国强. 2017. 青藏高原地形重力波拖曳的初步分析及数值模拟研究[J]. 气象学报, ():-, doi:10.11676/qxxb2017.016
青藏高原地形重力波拖曳的初步分析及数值模拟研究
Preliminary Analysis about the Gravity Wave Drag on Qinghai-Tibet Plateau and Study of Numerical Simulation
投稿时间:2016-05-23  最后修改时间:2016-09-26
DOI:10.11676/qxxb2017.016
中文关键词:  次网格地形, 重力波拖曳, 阻塞拖曳,数值模式
英文关键词:sub-grid  orography, gravity  wave drag, blocking  drag,numerical simulation
基金项目:国家自然科学基金;国家重点基础研究发展计划
作者单位E-mail
王宇虹 Service Center of Public Meteorology, China Meteorological Administration wangyhcams@163.com 
徐国强 国家气象中心/数值预报中心 xugq@cma.gov.cn 
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中文摘要:
      针对目前对青藏高原大地形激发的重力波拖曳相关问题还不十分清楚,在GRAPES_Meso模式中引入次网格地形重力波拖曳参数化方案,通过数值试验初步研究了青藏高原地区次网格地形重力波拖曳的一些相关参数,结果指出:(1)沿30°N地形重力波拖曳的垂直分布显示,阻塞拖曳主要存在于模式的低层(1-5层),重力波拖曳主要存在于模式的第5-10层;从水平分布看,模式第3层以阻塞拖曳为主,主要位于青藏高原边缘地区,阻塞拖曳大值区沿喜马拉雅山脉走向和青藏高原东坡;模式第5层以重力波拖曳为主,主要位于青藏高原东部地区和云贵高原的北部边缘。(2)弗劳德数和气流绕流高度分析表明,在青藏高原喜马拉雅山脉一带和高原东部边缘地区,气流爬坡能力强,同时在这一地区绕流高度最高;弗劳德数越大的地区绕流高度距离地表越高。(3)采用次网格地形重力波拖曳参数化方案后,对于低层和高层地形重力波破碎的发生有更准确的描述,地形重力波是向上垂直传播的。(4)个例和批量试验检验结果表明,采用次网格地形重力波拖曳参数化方案对于风场和降水模拟有正效果,提高了模式预报的准确率。
英文摘要:
      The gravity wave drag triggered by Tibetan Plateau remains unclear nowadays. To address the problem, a scheme for subgrid-scale orographic gravity wave drag parameterization was introduced to GRAPES Meso and sets of numerical experiments were conducted. Several conclusions are drawn from the results: (1) According to the vertical distribution of orographic gravity wave drag along 30°N, blocking drag exists mainly in lower levels (from level 1 to 5) while gravity wave drag exists mainly in the levels from level 5 to 10. According to the horizontal distribution, the blocking drag, which is dominated on level 3, exists mainly in the margins of Tibetan Plateau, of which the area of large values crosses from the Eastern Tibetan Plateau to the Northern Yunnan-Guizhou Plateau. (2) The analysis of the Froude number and the circumflow altitude shows strong gradability and thus highest circumflow altitude of the airflow in the area of Himalayas and the margin of Eastern Tibetan Plateau. The larger Froude number of the area, the higher circumflow altitude of the airflow. (3) With the adoption of the subgrid-scale orographic gravity wave drag parameterization, the model results reflect more accurate representation of the breaks of orographic gravity waves on lower and higher levels, as well as its vertically upward transport. (4) Moreover, both the single case and the batch tests show positive impact on the simulation of wind field and precipitation, which leads to the improvement of model prediction accuracy.
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