大气科学2012，Vol.36Issue(1)：47-62,16.
等σ面相当重力位势分析方法及其对高原低涡个例的检验应用
Analysis Method of Equivalent Isobaric Geopotential on σ Coordinate and Its Application to a Vortex in the Tibetan Plateau
摘要
Abstract
Due to the topographic effect of the Tibetan Plateau and its vicinity, some small but strong high and lowpressure systems often occur on the isobaric levels of the lower atmosphere by extrapolation, and the real systems cannot be reflected clearly. Therefore, it is still a difficult problem to analyze and diagnose the vortexes near the surface of the Tibetan Plateau with current isobaric analysis methods. In recent years, there has been significant progress in the numerical models, but the problem of weather analyses near the surface of Tibetan Plateau is not yet solved well. One of the reasons is that the pattern of geopotential height contour on the terrain following σ coordinate commonly used in models is similar to the topography and cannot represent the synoptic systems.In the article, a new variable, which is referred to equivalent isobaric geopotential (φe) and satisfies quasi-geo-strophic relation, is introduced based on the averaged harmoic-cosine vecter decomposition in a limited region. It can be used in the same way as the geopotential used on p coordinate. As an example, a eastward moving Tibetan Plateau vortex is analyzed. The results show some small but low and high systems always exist over the Tibetan Plateau due to extrapolation in the sea level pressure field, but at σ=0. 995 level, the process of the eastward moving Tibetan Plateau vortex coupling with the southeast vortex at lower levels can be depicted well by the distribution of φe and these artificial systems in the Tibetan Plateau disappear. Therefore, the weather system near the surface of Tibetan Plateau can be analyzed well with the analysis method of equivalent isobaric geopotential height On the other side, the distribution of φe can link the synoptic pattern over the Tibetan Plateau with that in its lower reaches, which is favorable to reveal how the systems over the plateau impact the weather in the lower reaches.关键词
平均的调和-余弦算法/等σ面相当重力位势/高原低涡Key words
averaged harmonic-cosine series expansion/equivalent isobaric geopotential on σ coordinate/vortex in the Tibetan Plateau分类
天文与地球科学引用本文复制引用
周玉淑,邓涤菲,Chen Qiu-shi..等σ面相当重力位势分析方法及其对高原低涡个例的检验应用[J].大气科学,2012,36(1):47-62,16.基金项目
国家自然科学基金资助项目41075044、40975034,科技部公益性行业(气象)科研专项GYHY200906004,国家自然科学基金资助项目40930950 （气象）
