A climatological study of the strongest local winds of Japan “Inami‐kaze”

Abstract

This study examines the meteorological and climatological features of the Inami‐kaze in the Tonami Plain, the strongest local winds in Japan. The plain faces the Sea of Japan on the north side, while the remaining three sides are surrounded by high mountain ranges. An interview survey to local residents and the distribution of windbreak trees both indicate that the Inami‐kaze is localized to a surprisingly small region near the Inami town (about 6 km parallel to the mountain ridge and 3 km perpendicular to it), at the base of a very small saddle‐like topography in the mountain ridge. Wind statistics with a dense observation network during 2006–2014 (28 Inami‐kaze events) supports the above finding. Indeed, the wind speed is mostly (95%) below 11 m/s at the Tonami town, just 5 km away from the Inami town, while the Inami‐kaze (≥15 m/s) blows at the Inami town. Such a spatial pattern should be formed as a result of downslope windstorm with hydraulic jumps, which is indicated from the internal Froude number change across the mountain (0.9 at the upstream, 1.4 at the mountain top, and 0.3 at downstream). The required synoptic atmospheric condition for the Inami‐kaze is the pressure pattern “extratropical cyclone in the Sea of Japan.” The sufficient condition is the SSW–SSE wind (≥25 m/s) or south wind (around 20 m/s) at the 800‐pressure level over the mountain chain, indicating the allowed directional window is very narrow. On the other hand, the Inami‐kaze has an aspect of foehn. While the Inami‐kaze occur, the potential temperature at the Inami town tends to be higher by 4.7 K on average than in the windward plain on the Pacific Ocean side.

Thermodynamics and airstreams of a south foehn event in different Alpine valleys

“…These winds exhibit archetypal characteristics, as they are warm, dry, and often gusty in nature. Their frequent occurrence is recognised in various regions of the world, among them being the Chinook in the western United States (Glennf, 1961), the Puelche in Chile (Beusch et al ., 2018; Montecinos et al ., 2017), and the Inami‐kaze in Japan (Koyanagi and Kusaka, 2020). Their socio‐economic impact has been stated in terms of increased risk for wildfire ignition and spread (Sharples et al ., 2010) or infrastructural damage and a risk for aviation (Richner and Hächler, 2013).…”

Balancing Accuracy and Efficiency of Atmospheric Models in the Northern Adriatic During Severe Bora Events

“…Additionally, severe bora events are known to strongly impact a great number of human activities in the coastal Adriatic regions (Biolchi et al., 2019; Davolio et al., 2015; Kozmar et al., 2012; Lepri et al., 2017; Niziol et al., 1995; Radić et al., 2003; Stocchi & Davolio, 2017). Bora‐like orographically driven severe windstorms are also found all around the world (e.g., Burlando et al., 2017; Hanesiak et al., 2013; Koletsis et al., 2009; Koyanagi & Kusaka, 2020; Shestakova & Moiseenko, 2018; Tollinger et al., 2019) and the first comprehensive research of the Adriatic bora was performed by Japanese researchers (Yoshino, 1976) due to similarities with their own local events.…”

Mesoscale and local‐scale climatology of extreme temperature events in Niigata, Japan

“…Takane et al (2014) revealed that the most severe ETE cases occurred after the development of the "whale-tail" pressure pattern, four or more consecutive days of clear skies were formed, and foehn warming occurred. It is noteworthy that the foehn winds causing ETEs in this area are weak winds, unlike foehns in other regions (Mori and Sato, 2014;Koyanagi and Kusaka, 2020;Kusaka et al, 2021).…”