Three Local Winds that Blow on the Tonami Plain

  • Takuma KOYANAGI, 2015: Three Local Winds that Blow on the Tonami Plain .

Abstract


In this study, climatological characteristics of three local winds — “Shogawa-arashi,” “Inamikaze,” and “Iou-oroshi” — found in the Tonami Plain, which locates in Toyama Prefecture, were statistically investigated. First, these three local winds were defined referring local materials in Tonami Plain, the interview to people living there. Then, in which season and time zone, and in what type of synoptic atmospheric pressure field these winds occur, respectively, were investigated. As the results, the following things are revealed: Shogawa-arashi occurs mainly through fall and early winter (October through December) and almost only in the night time and this wind occur mainly when the high atmospheric pressure covers Japan; Inamikaze occurs almost only in spring (March through May) and fall (October and November), and it occurs when low atmospheric pressure locates in the west part of the Sea of Japan; Iou-oroshi occurs mainly in spring (April) and early winter (December). The latter two winds were revealed to occur both in day and night. Next, Locality of the three winds was investigated by comparing the observed wind direction and speed data in three observation station in the Tonami Plain. As a result, Shogawa-arashi and Inamikaze was founded to blow only near the entrance of the Shogawa River Valley and in Inami-Shogawa, respectively, while Iou-oroshi didn’t show obvious locality. Inamikaze is considered to be strengthened by topographic effects. Finally the tendency of temperature and humidity when these three winds occur, respectively, were investigated. As a result, Shogawa-arashi showed a tendency to dry up the air. Inamikaze showed a tendency to both warm up and dry up the air, which meets the characteristic of foehn. On the other hand, Iou-oroshi didn’t show the obvious characteristics. Iou-osohi is likely to be driven by topograshic effect.

Keywords: local wind, Tonami plain, foehn, topographic effect, pressure distribution