Topics 2017.09.22

Ocean Precipitation Long-Term Trend Around Japan

eisei_201709a.png Figure 1:ツ黴€ The rainbow at the Sendai Bay taken on Dec.05, 2016.

ツ黴€ ツ黴€ツ黴€ Here we talk about the long-term trend of the ocean precipitation around Japan.ツ黴€ The map of the averaged ocean precipitation around Japan are shown in Figure 2.ツ黴€ This figure was made out of the hourly precipiation data from 2007 to 2016 by the Japan Meteorological Agency's numerical model results.ツ黴€ According to Figure 2, the high precipitation area, which is colored yellow and red, extends from near Taiwan to the west of Okinawa-Amami Islands in East China Sea.ツ黴€ Such area appears in the sea south of Kyushu, Shikoku and Honshu Islands and also appears in the sea east of Boso Penunsula.ツ黴€ It is noted that the distribution of these high precipitation areas corresponds well to the ocean currents, Kuroshio and Kuroshio Extension.

ツ黴€ ツ黴€ツ黴€ Figure 2 also shows the averaged precipiation over the land.ツ黴€ The averaged land precipiation is clearly affected by geographical features, such as mountains and valleys.ツ黴€ On the other hand, the ocean current seems to play an important role in making the long-term trend of the ocean precipiation.ツ黴€ As mentiond above, Kuroshio and Kuroshio Extension could make a bias of the precipiation in the ocean around Japan.ツ黴€ Note that Figure 2 was made only by the numerical model results.ツ黴€ Further study is needed to be closer to the real of the ocean precipitation.


Figure 2:ツ黴€ The averaged precipiation map around Japan.ツ黴€ The hourly precipiation data from 2007 to 2016 by Japan Meteorological Agency's numerical forecast model outputs are used.

(by Futoki Sakaida and Kazuki Hidaka, Satellite oceanography laboratory, CAOS)ツ黴€

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