doi:  10.3878/j.issn.1006-9895.1806.18126
不同定义的湿位涡分析及在台风中的诊断

Analysis of Different Moist Potential Vorticity Forms and Their Comparison in Typhoon Diagnosis
摘要点击 52  全文点击 19  投稿时间:2018-02-08  修订日期:2018-04-27
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基金:  国家自然科学基金(41375063,41705037)资助,
中文关键词:  湿位涡  位温  干湿分量  台风  诊断
英文关键词:  Moist potential vorticity  Potential temperature  Dry and moist component  Typhoon  Diagnosis
        
作者中文名作者英文名单位
刘赛赛LIU Sai Sai中国人民解放军31010部队
张立凤ZHANG Li Feng全军危险性天气监测预警研究中心/国防科技大学气象海洋学院
赵艳玲中国人民解放军31010部队
引用:刘赛赛,张立凤,赵艳玲.2018.不同定义的湿位涡分析及在台风中的诊断[J].大气科学
Citation:LIU Sai Sai,ZHANG Li Feng.2018.Analysis of Different Moist Potential Vorticity Forms and Their Comparison in Typhoon Diagnosis[J].Chinese Journal of Atmospheric Sciences (in Chinese)
中文摘要:
      本文对不同定义的湿位涡做了理论分析,并利用1522号台风“彩虹”的数值模拟结果对各种湿位涡进行了诊断。主要结论有:经典湿位涡、广义湿位涡和改进湿位涡的差异主要是由不同定义的位温造成的,相当位温,广义位温和修改位温的构成均是在位温基础上添加一显含水汽的附加量;经典湿位涡、广义湿位涡和改进湿位涡的构成均能分为干、湿分量两部分,其干分量表达式相同,都与Ertel干位涡的定义一样,水物质相变潜热的影响隐含在位温中;不同定义湿位涡的本质差异表现在不同的湿分量上,湿分量的表达式中显含了水物质的作用。对台风的诊断分析发现,改进湿位涡分布与Ertel干位涡非常相似,呈现中空分布的位涡塔结构,大值区对应眼墙内侧,改进湿位涡湿分量与经典湿位涡的湿分量分布相似,只是湿分量的绝对值更小,这反映了改进湿位涡既能保持干位涡的分布特征,其分布和演变可反映台风的结构和演变,又能合理地体现水汽分布的影响,所以在台风诊断中有更广泛的应用前景。经典湿位涡在低层表现为负值,这与水汽梯度的分布关系很大,但与垂直速度、潜热加热大值区等都没有很好的匹配关系,用其分析台风结构和演变具有一定局限性;广义湿位涡其形式较复杂,仅在近饱和区域才能发挥其诊断优势。
Abstract:
      In this paper, a theoretical analysis of different moist potential vorticities is made and a numerical diagnosis of the typhoon Mujigae (1522) is performed with different potential temperatures and potential vorticities. The results show that, the differences between the Equivalent Potential Vorticity, the Generalized Moist Potential vorticity and the Modified Moist Potential Vorticity are mainly caused by the different potential temperatures which are based on the original Potential Temperature, in which an additional explicit variable of water vapor is added. The Equivalent Potential Vorticity, the Generalized Moist Potential Vorticity and the Modified Moist Potential Vorticity can be divided into two parts: the dry component and the moist component. The dry components of these moist potential vorticities are same as the Ertel Potential Vorticity and implicitly contain the effect of latent heat in phase change. The essential difference between these moist potential vorticities is reflected in their moist components, which can explicitly contain the effect of water vapor. Based on the simulation results and diagnostic analysis of the typhoon, it is found that the distribution of the Modified Moist Potential Vorticity is like a “hollow tower” and the high value area distribute in the inside of the eye wall, which is very similar with that of the Ertel Potential Vorticity. And the distribution of the Modified Moist Potential Vorticity’s moist component is also very similar with that of the Equivalent Potential Vorticity’s, but the absolute value of the former is smaller. These indicate that the Modified Moist Potential Vorticity can maintain the characteristics of the original Ertel Potential Vorticity. It can not only reflect the structure and intensity change of a typhoon but also reflect the influence of water vapor distribution reasonably. As showed in the above, the Modified Moist Potential Vorticity has a potential application in the diagnosis and forecasting for typhoon. The value of Equivalent Potential Vorticity is negative in the low level, which is tremendously related to the distribution of water vapor gradients. But it doesn’t have a good matching relationship with the vertical velocity, latent heat heating, and other factors, thus leading a limited use in analyzing the typhoon structure and evolution. The Generalized Moist Potential vorticity has a complex form and can only show its diagnostic advantages in nearly saturated air.
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