Whale tail shape - Whale tail shape

...When a high pressure system over the sea east of Honshu extends westward and covers the vicinity of Japan, it is sometimes called an eastern high pressure system and a western low pressure system. Another small high pressure system is often seen near the Korean Peninsula, and the shape of the isobars covering the vicinity of Japan resembles the shape of a whale, so the weather chart is sometimes called a "whale tail type" because the area around the Korean Peninsula is like the tail of a whale. In general, even in seasons other than summer, when a migratory high pressure system covers the vicinity of Japan and there is a small high pressure system further west near the Korean Peninsula or the Yellow Sea, the migratory high pressure system tends to stagnate and sunny weather continues for a long time. ...

*Some of the terminology that refers to the "whale tail shape" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…本州東方海上の高気圧が西に張り出して日本付近を覆うときは東高西低型ということもある。朝鮮半島付近にしばしば別の小高気圧がみられ，日本付近を覆う等圧線の形がクジラの姿に似て，朝鮮半島付近があたかもクジラの尾にあたるところから〈鯨の尾型〉の天気図と呼ぶこともある。一般に夏以外の季節でも，日本付近が移動性高気圧に覆われて，さらに西の朝鮮半島や黄海付近に小さな高気圧があるときは移動性高気圧は停滞して晴天が長続きする傾向がある。…

※「鯨の尾型」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報