紀要論文

Climatological Features of Winter Lightning Activity in the Coastal Area of Sea of Japan, Tohoku and Hokuriku District

eng

00753467

https://doi.org/10.15002/00010793

Japan Climatology Seminar

2014

38

44

2014-12

Version of Record

This research clarified some statistical features of winter lightning activity in the coastal areas of Sea of Japan based on observational data obtained by Lightning Location System(LLS) in Tohoku district. Analysis of data indicated that during the cold season, the highest lightning frequency was displayed in the late autumn(Oct-Nov), when intensive lightning activity occurred in the coastal areas of Aomori and Akita prefectures. In the mid-winter season(Dec-Jan), the region of intense lightning activity moved southward to Yamagata and Niigata prefectures. Lightning frequency in the late winter season(Feb-Mar) was the lowest, with the region of intense lightning activity moving northward to Yamagata and Akita prefectures. An examination of ERA-interim reanalysis data revealed that during lightning days, Tohoku and Hokuriku districts were located near the southern part of the cyclone passing over Sea of Japan. Moreover, seasonal variation of lightning frequency patterns might be related to the prevailing wind direction in the study area. In the late autumn season, the prevailing surface wind direction over Sea of Japan was west to southwest, which created a strong wind convergence zone near the coastal areas of Aomori and Akita prefectures. However, the convergence zone moved southward when the wind direction changed northward in the mid-winter season. During the late winter season, the changes in wind patterns caused the convergence zone to be again formed near Aomori and Akita prefectures. These results are consistent with the changes in lightning frequency pattern.

Article

AA00249627