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題 名 | 中性濕靜力穩定面的氣候特徵=General Characteristics of the Moist Neutral Static Stability Surface |
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作 者 | 李永安; 董昀嵐; | 書刊名 | 大氣科學 |
卷 期 | 26:2 1998.06[民87.06] |
頁 次 | 頁133-147 |
分類號 | 328.2 |
關鍵詞 | 中性濕靜力穩定面; 相當位溫; 濕等熵座標; Moist neutral static stability surface; Equivalent potential temperature; Moist isentropic coordinates; |
語 文 | 中文(Chinese) |
中文摘要 | 不論從濕靜力穩定的角度或從濕等熵座標中相當密度的角度來看,中性濕靜力穩 定面〔δθ e ╱δ z=0 的面〕都應被視為對流層內的一個邊界面。為了瞭解其氣候基本特 性和所蘊涵的訊息, 我們利用 ECMWF/TOGA 1986 至 1993 八年的資料來分析長期平均的中 性濕靜力穩定面所存在位置的壓力與風場。我們發現,大體而言,中性濕靜力穩定面上的高 度〔以壓力表示〕分佈於熱帶地區最高,極地地區最低,而中緯度地區則有很強的梯度。但 是由於中性濕靜力穩定面所存在的位置深受水氣分佈的影響,因此其上變數場的結構也受到 大氣運動、下邊界條件與季節變化的影響而有強烈的局部差異。所以,相較於單一等壓面, 此面上的分析蘊涵了更多對流層結構的訊息。因為臺灣位於中性濕靜力穩定面高度季節遷移 最明顯的區域,我們發覺藉由此特性可以很容易的決定出臺灣地區的季節遷移過程,特別是 夏季的肇始與衰退的日期。 |
英文摘要 | Either from moist static stability or from the equivalent density in moist isentropic coordinate points of view, we noted that the moist neutral static stability surface (surface of δθ e ╱δ z=0) should be recognized as a boundary surface embedded within the troposphere. To understand this surface's general characteristics, we used 8 years (1986-1993) of ECMWF/TOGA data to analyze long term behaviors of various variables on this surface. We found that, the altitude of the moist neutral static stability surface is generally decreasing from the tropics toward both poles with sharp gradient located at mid-latitudes. Nevertheless because moisture distribution has great influence on the location of this moist neutral static stability surface, hence variables' behaviors on this surface showed intimate relations not only with motions within the troposphere but also with lower boundary conditions. Therefore, in comparison with those on single isobaric surface, variables' behaviors on this surface showed richer structures. Furthermore we found that the seasonal migration of the height of the moist neutral static stability surface is very pronounced in East Asia. Hence seasonal transition process as well as the onset and the retreat of summer season near Taiwan can be easily identified in time series of the height of the moist neutral static stability surface. |
本系統中英文摘要資訊取自各篇刊載內容。