Tropical cyclone induced precipitation over Japan using observational data

Abstract

Tropical cyclone (TC) induced precipitation (TCP) over Japan is evaluated with the rain gauge observation based gridded dataset APHRO_JP. The TC-influenced frequency reaches a maximum in the Nansei Islands and decreases monotonically with latitude. On the other hand, the distribution of TCP indicates different characteristics from the one of TC-influenced frequency. The largest annual TCP, 500 mm yr -1 or more, occurs over eastern Kyushu (E-Kyushu), southern Shikoku (S-Shikoku), and the eastern Kii peninsula (E-Kii), where it accounts for 15% or more of the total precipitation. The maximum daily TCP amounts to 200 mm d -1 in those three areas, which are all located on the eastern side of Japan and correspond to eastward or southeastward topographic inclines. A significant relationship is found between the amount of annual TCP and topographic incline, and the large amount of TCP concentrates in the eastward or the southeastward inclines. The extreme daily TCP once every 50 years is also evaluated. The extreme daily TCP is estimated to be 500 mm d -1 comparable to the climatological annual TCP in E-Kyushu, S-Shikoku, and E-Kii. These three areas appear to be the most hazardous part of Japan in terms of TCP.