東亞地區冷暖冬極地氣團與大氣環流的等熵分析

本研究利用950百帕面東亞地區溫度距平值的大小，選取1971、1977、1986年為冷冬年，1973、1979、1980年為暖冬年。分別由冷冬年與暖冬年的等熵面合成圖的分析，來探討東亞冬季大尺度環流型態與氣溫變化的關係。結果顯示，從逐月等熵位渦分析，可清楚地瞭解極地冷氣團於冬季發展、南移、增強，最後向北消退的環流特性。冷冬年在我國東北地區有一較強的等熵位渦極值中心存在，顯示較冷的冷氣團在此處有氣旋式渦旋運動，造成高位渦西側強烈的冷空氣南侵；而暖冬年高位渦區偏北，且強度較小，冷氣沒有大量南下。對應於歐洲槽的高位渦區冷冬年於30°E～45°E間加強，而暖冬年在50°E～70°E間發展，使得貝加爾湖上空的高位渦區於冷冬年呈西北－東南走向，形成具強烈冷平流的斜壓區，由60°N以北的高空冷心向南衝到東亞地區，造成大陸東南地區的氣溫偏低；而暖冬年高位渦區則呈東西走向，環流形勢較接近正壓，空氣由高空冷心南側向東南流至大陸東南，氣溫平流較弱。

關鍵字

冷氣團；等熵面；位渦；冷冬；暖冬

並列摘要

The eastern Asia area mean temperature data from 1970-1986 were used to calculate the temperature frequency distribution in winter. The warm or cold winter was defined by the standard deviation of the temperature anomaly. We found that 1971, 1977, 1984 and 1986 were cold winter years; while 1973, 1979 and 1980 were warm winter years. The potential vorticity at isentropic surface was examined to discuss the difference between the cold winter and warm winter in this paper. The high potential vorticity (HPV) center were located at the northeast area of China in cold winter. It mean that the more serious air mass with cyclonic motion would lend the cold air outflow to the south of the continent. But, the weak HPV was located in Siberia in the warm winter. Another significant character is the location of the west HPV which is correspond to the European though. In the cold winter, it was located between 30°E~45°E and the HPV near Baikal Lake was oriented as NWSE. The strong cold advection were happened in the baroclinic domain. But the HPV area was oriented as W-E in warm winter. The flow was along the southern part of the cold air mass toward southeast and the temperature advection was not too strong in these years

並列關鍵字

Cold Air Mass ； Isentropic Surface ； Potential Voricity ； Cold Winter ； Warm Winter

國際替代計量

東亞地區冷暖冬極地氣團與大氣環流的等熵分析

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