第4卷‧第5期,
197605
, pp. 40-57
臺灣地區乾旱長期預報之研究
- 作者:
王博義
- 作者服務機構:
中央氣象局
- 中文摘要:
乾旱是氣象災害的一種,源自氣候異常、雨水失調之大氣自然現象。有關乾旱的研究,可促進加強如何利用氣象資料之計畫土地利用及在農業上的經營,而實施氣侯水利之管理灌溉方法,以求水資源控制之需要。 設以每侯(五日)平均雨量劃分之乾旱期及絕對乾早期,全年四季中臺灣各地均有可能發生乾旱期,尤以西南部沿海平原,冬季有絕對乾旱期之出現。 以掌握(1)高空長波主槽之分析;(2)臺灣梅雨之起止;(3)颱風之轉向等各項因素形成之物理基礎,則可作為乾旱期預報之根據。 綜合乾旱期之特性,分析其形成理由有下列四種: 1.秋末冬初沒有「臺灣秋颱」或颱風在126°E以東轉向北進。 2.地面大陸高壓系統南侵南海,台灣上空西北氣流旺盛,「台灣東方主槽」滯留時。 3.太平洋反氣旋異常發展,滯留鋒在黃河流域徘徊,高壓脊線平均位在28°N,主軸為東西走向。 4.大陸移動性高氣壓位於較低緯度( 32°N)之中國東海區,主軸為南北方向,但持續性長者五至十日;短者三至四日左右。
- 英文摘要:
A great drought is one kind ofmeteorological disasters. It is a naturalatmospheric phenomenon caused byabnormal climate and uneven precipit-ation. The concerned research may en-courage the application of historicalmeteorogicsl data in land use planningand agricultural management. This inturn will lead to the, implementationof climatic water conservation measuresand to required controls on water re-sources. If we use the mean precipitation offive-day periods to distinguish droughtconditions, then we can say that dur-ing the four seasons of a year, all are-as of Taiwan are likely to experiencea period of drought and that duringwinter absolute drought occurs in thecoastal plains of southwestern Taiwan. Reliable information concerning(1)distribution of the major troughs ofhigh altitude long waves, (2) the be-ginning and ending dates of Taiwan'sraining seasons and (3) the movementof typhoons, can form the basis of aphysical model, and thus be used inthe predication of drought periods. In this paper, We obtain somegeneral conclusions which explain thecharacteristics of Taiwan's droughtperiods:(1)During last autumn and early win- ter Taiwan either does not exper- ience autum typhoons, or the ty- phoons turn northward east of 1260 Elongitude.(2) The surface continental high pres- sure system noves southward, to the South China Sea, the northwest air current over Taiwan is very strong and the major trough remains sta- tionary east of Taiwan.(3)Pacific anti-cyclones develop ann- ormally strong, the stationary front oscillates in the Yellow River Basin the high pressure ridge is usually located 28°N with the main axis running east and west.(4) The continental migratory high pressure is located at relatively lower latitudes ( 32°N) of the East China Sea with the main axis lying in a north and south direction and persisting for 5 to 10 days at the maximum and for 3 to 4 days at the minimum.
- 中文關鍵字:
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- 英文關鍵字:
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