岡山大学理学部地球科学教室 Acta Medica Okayama 1340-7414 20 1 2013 2004年10月後半の台風23号に伴う日本列島での広域の降水（台風18号と比較して） 13 24 EN Ai Satake Kuranoshin Kato Yoshinori Mori Yasuhiro Goda Shoichiro Ikeda Osamu Tsukamoto 10.18926/ESR/52166 Rainfall distribution in the Japan Islands associated with the approach of Typhoon No.23 around 20 October 2004 (referred to Ty0423, hereafter) showed considerably different features from those in late summer of this year. The present study examined the detailed rainfall features around the Japan Islands brought by Ty0423 and the atmospheric processes based on the operational observation data by the Japan Meteorological Agency (JMA), comparing with those in association with Ty0418 around 7 September 2004. During the stage when Ty0423 was approaching or landing on the western part of the Japan Islands, the areal mean precipitation from Kyushu to Kanto District attained much larger than that for Ty0418, with wider extension of the area with the large amount of precipitation. It is interesting that, although the intense rainfall was observed only at the upstream side of the mountain range from Kyushu to Honshu District for Ty0418 except for the area near its center, strong rainfall with 10~30 mm/h persisted in wider regions from the western to the eastern part of the Japan Islands, resulting in the considerably large total rainfall for Ty0423. As for the case for Ty0423, the surface front with stable frontal surface was located just to the east of the Ty0423 center just before its landing at the Japan Islands. Thus, the huge moisture inflow mainly in the eastern region from the typhoon center seems to be redistributed widely over the Japan Islands area associated with the large-scale convergence around the stable frontal surface. In late October, the colder air associated with the high pressure system in the eastern Siberia can cover the northern part of the Japan Sea area as the seasonal march. Such basic field might be favorable for sustaining the synoptic-scale front just around the southern coast of the Japan Islands, even when the strong southerly wind invades associated with the typhoon approach there. No potential conflict of interest relevant to this article was reported.

岡山大学理学部地球科学教室 Acta Medica Okayama 1340-7414 19 1 2012 地上梅雨前線の南方の九州における 線状降水帯の集団の維持について （2001年6月19日頃の事例解析） 39 50 EN Yasuhiro Goda Kuranoshin Kato Osamu Tsukamoto 10.18926/ESR/49212 A case study on persistent appearance of the ensemble of precipitation bands in the warm sector of the Baiu front in Kyushu District, the western part of Japan around 19 June 2001 was performed based on the operational observational data. Around 00UTC (09JST) 19 June when the Baiu front on the surface weather map was still located about a few 100kms to the north of Kyushu, the number and the total area of the meso-β or γ-scale line-shaped precipitation bands increased around Kyushu rapidly. These precipitation bands had been sustained there and gradually gathered each other to change into the Baiu frontal precipitation zone extending from the northern Kyushu to Seto-Naikai (Seto Inland Sea) around 09UTC (18JST) 19 June (the intense rainfall zone was still located in the warm sector of the Baiu front). Until ~09UTC (18JST) 19 June, the moist air flow with the latently unstable stratification had been sustained around Kyushu corresponding to the low-level southerly wind toward the surface Baiu front to the north of Kyushu. This large-scale situation would contribute greatly to the maintenance of the ensemble of the line-shaped precipitation bands in the warm sector of the Baiu front. No potential conflict of interest relevant to this article was reported.