李驰钦,左群杰,高守亭,鲁蓉. 2018. 青藏高原上空一次重力波过程的识别与天气影响分析[J]. 气象学报, (0):-, doi:10.11676/qxxb2018.026
青藏高原上空一次重力波过程的识别与天气影响分析
LI Chiqin ZUO Qunjie GAO Shouting LU Rong
投稿时间:2017-09-30  修订日期:2018-01-03
DOI:10.11676/qxxb2018.026
中文关键词:  重力波,WRF模式,青藏高原,冬季降雪,对流
英文关键词:Gravity  wave, WRF  model, Tibetan  Plateau, winter  snowfall, convection
基金项目:国家基础研究重大项目基金
作者单位E-mail
李驰钦 中国科学院大气物理研究所云降水物理与强风暴重点实验室中国科学院大学 lichiqin@mail.iap.ac.cn 
左群杰 中国科学院大气物理研究所云降水物理与强风暴重点实验室 zqj@mail.iap.ac.cn 
高守亭 中国科学院大气物理研究所云降水物理与强风暴重点实验室 gst@mail.iap.ac.cn 
鲁蓉 中国科学院大气物理研究所云降水物理与强风暴重点实验室中国科学院大学 272750136@qq.com 
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中文摘要:
      应用资料和方法再分析资料、多套卫星反演资料和WRF中尺度数值模拟资料,目的识别了2005年1月10日青藏高原上空一次重力波过程,以及重力波对高原西部降雪的影响。结果结果表明,此次重力波位于急流出口区的左方, 以西南-东北走向覆盖了高原大部分地区。大尺度的冷暖平流相间分布和不断增强的非平衡流为重力波的形成提供了有利背景场。小波交叉谱分析显示垂直涡度与水平散度在对流层中层满足重力波的极化性质,在高原西部的上升支对应有降雪过程发生。WRF可以较好地再现这一过程,并且能够模拟出再分析资料中所无法分辨的中尺度重力波。结论数值模拟表明,高原近地面强烈非绝热加热使得低层大气静力不稳定,在近地面暖区触发对流后引起高层凝结释放潜热,低层融化冷却,有利于激发重力波,并在其上升支产生固态凝结物,随后到来的冷气团提供了有利的水汽输送条件,大范围的弱抬升运动取代了原间隔进入降雪区的强对流上升支,使得固态凝结物得以落至地面,最终在高原西部形成本次降雪过程。
英文摘要:
      Based on reanalysis data, multiple sets of satellite retrieval data and the WRF model simulation data, a gravity wave event is identified over Tibetan Plateau on 10 January 2005. The role of the waves in snowfall over central plateau is also studied. It is found that gravity wave covered most part of the plateau from southwest to northeast, situated to the left exit of jet stream. The wave-like temperature advection pattern and strengthening unbalanced flow provided environment in favor of gravity waves. Wavelet cross spectrum analysis shows that vertical vorticity and horizontal divergence in middle troposphere were consistent with polarization relation in ducted gravity waves. Snowfall was detected over the updraft region in the central plateau, which can be simulated by WRF. Simulation can also present mesoscale gravity wave that can hardly be identified in reanalysis data. Numerical simulation shows that the strong diabatic heating near the surface resulted in static instability. Convections were thus easily initiated over warmer region and led to latent heat release by condensation over high altitude. The melting-induced cooling near the ground associated with convection forced the gravity wave development. The formation of solid hydrometers took place over updraft regions, and subsequent arrival of cold air provided favorable condition for water vapor transport. Weak large-scale ascent replaced the strong updrafts that entered the snow region intermittently. Solid hydrometers then fell onto the ground and the precipitation event finally happened over central Tibetan Plateau.
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