東アジアにおける卓越気圧配置型の季節推移からみた近年の気候変動 Climatic Variations in Recent Years from the Viewpoint of the Seasonal Transition of Prevailing Pressure Pattern Types over East Asia

この論文にアクセスする

この論文をさがす

抄録

東アジアにおける気圧配置型の出現頻度からみた気候変動の実態を,1941年から1985年までの45年間について論じた.1970年代以降をそれ以前と比較すると,冬型高頻度期間の長期化,厳冬季の早期出現,春季移動性局気圧卓越期の遅れ,梅雨前線活動の後半顕著・長期化,夏型高頻度期間の短縮,日本へ接近する台風(とくに秋台風)の減少,秋雨前線の早期出現・活動長期化,秋季移動性高気圧高頻度期間の早期終了といっ一連の傾向が特徴である.また1980年前後になり,.1960年前後と同様に,日本列島上の梅雨前線が活発になりやすい状態となったが,これは集中豪雨の多発と関連している.さらに,晴天のシンギュラリティとして知られる文化の日を含む11月2~6日は,確かに移動性高気圧に覆われやすく,経年変動も少ないが,同程度のシンギュラリティが春季の4月11~15日にも存在すること等新しい知見を得た.

Seasonal transitions and Climatic variations from the viewpoint of the occurrence frequency of atmospheric pressure patterns over East Asia are discussed in the recent 45 years (1941-1985). The category of the pressure pattern types which was formed by Yoshino (1968) has been applied to many studies (ex.: Nomoto, 1975; Komabayashi and Nakamura, 1976; Hohgetsu, 1979; Hayashi, 1987). The pressure pattern calendar on the basis of this category was made by Yoshino and Fukuoka (1967), Yoshino and Kai (1974) and Yoshino and Yamakawa (1985).<br> The following is the classification of main pressure patterns over East Asia in this study.<br> I: West-high, east-low pattern or winter monsoon pattern.<br> II: Trough pattern.<br> II a: passing low over Hokkaido (the second biggest, northern island in Japan) or north of it.<br> II b: Passing low over the Sea of Japan.<br> lI c: Passing low along the Pacific coast.<br> lI d: Passing coupled lows across Japan.<br> III: Migratory anticyclone pattern.<br> IV: Stationary frontal pattern (The defined area of this category is shown in Fig. 11).<br> IVa: Stationary front over Honshu (the biggest, main island in Japan).<br> IVb: Stationary front along the Pacific coast of Japan.<br> V: South-high; north-low pattern or summer monsoon pattern.<br> VI: Typhoon pattern.<br> The main results in this study are as follows: 1) Six seasons and one specific period in Japan are recognized (Fig. 12) from the viewpoint of occurrence frequency over 30% during 1941-1985 of the main pressure pattern types: namely each index are Type I for the winter season, Type III for the spring and autumn seasons, Type V for the summer season, Type N for the Baiu season (early summer rainy season), Type (IV+II b, c, d+VI) for the Akisame season (early autumn rainy season) and. Type VI for the Typhoon period.<br> 2) The pentad (Nov. 2-6) including November 3, which is called the specific fine weather day, occupies the pretty much high frequency (51%) of migratory anticyclones. While in the pentad of April 11-15, the equivalently and considerably high frequency (52%) of migratory anticyclones appeares. (Fig. 3, Fig. 12).<br> 3) A singularity pentad of cyclonic or frontal pressure patterns accompanying the cloudy or rainy weather is June 25-29 (Fig. 7, Fig. 12), which was indicated by Maejima (1967, 1968).<br> 4) Around 1980, the Baiu fronts were more active over the Japanese Islands and were apt to cause heavy rain, as same as in the 1960's (Fig. 5).<br> 5) In the latest years (1971-1985), the autumn rainy season due to the fronts and cyclones became more active (Fig. 7, Fig. 12).<br> 6) The frequency of typhoons approaching to the Japanese Islands decreased during about the latest years, especially in autumn (Fig. 10, Fig. 12).<br> 7) In the latest years (1971-1985), comparing with the former years (1941-1970), the secular features of seasonal phenomena are noticed (Fig. 12); i, e, prevailing and longer winter, less frequent migratory anticyclones in the earlier spring, active Baiu fronts in the later period, less prevailing summer, more frequent autumnal fronts in the earlier and longer period, and less frequent migratory anticyclones in later autumn were often appeared. Probably, there is no causal relationship between these phenomena, but there are the correlations due to some causes of astronomy, upper air chemical content and circulation, sea or glacier.

収録刊行物

  • 地理学評論. Ser. A

    地理学評論. Ser. A 61, 381-403, 1988

    学術雑誌目次速報データベース由来

被引用文献:  11件中 1-11件 を表示

各種コード

  • NII論文ID(NAID)
    110000521276
  • NII書誌ID(NCID)
    AN1016484X
  • 本文言語コード
    ENG
  • 資料種別
    雑誌論文
  • ISSN
    00167444
  • NDL 記事登録ID
    3178773
  • NDL 刊行物分類
    ME25(気象--大気現象)
  • NDL 雑誌分類
    ZG1(歴史・地理)
  • NDL 請求記号
    Z8-571
  • データ提供元
    CJP引用  NDL  NII-ELS  J-STAGE 
ページトップへ