Numerical simulation study of the effects of foehn winds on white head incidences in Yamagata Prefecture, Japan

Abstract

Numerous studies have elucidated that white heads and chalky rice are caused by hot, dry and strong winds at night. However, these studies have only used synoptic weather charts and near‐surface observation data to confirm the role of foehn in white head occurrences. This study used a high‐resolution three‐dimensional numerical weather prediction model to show that strong foehn effects induced a significant number of white heads in rice in Yamagata Prefecture, Japan. The model accurately predicted and represented the location and timing of the observed white heads, occurring only in a limited area (87.1 ha) on the southwest side of Mt. Chokai during the nighttime. Specifically, the simulated nocturnal FTP (transpiration forcing) continuously exceeded 30 at that location. This high FTP was caused by high temperature (>24°C), strong wind speed (>8 m s−1) and low humidity (<65%) caused by the strong foehn winds descending over the southwest slope of the mountain. In the other areas, FTP did not exceed 30 because either wind speed, water vapour deficit or both were insufficiently high.

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

“…Furthermore, they affect agricultural production in foehn regions. Whereas foehn winds are found to promote white head occurrence on Japanese rice plantations (Asano and Kusaka, 2021), anecdotic evidence indicates that they are beneficial for wine production in Alpine foehn valleys (Walker and Ruffner, 1998). Recently, foehn flows have also been attributed a key role for surface melt on the Larsen C Ice Shelf in Antarctica (Elvidge et al ., 2020) and in northeast Greenland (Mattingly et al ., 2020).…”

Editorial: Atmospheric processes and applications in urban, coastal and mountainous terrain

“…Thomas et al (2021) evaluate the ability of three global reanalysis data sets (ERA-Interim, ERA5 and MERRA-2) to reproduce wind observations in different coastal regions of Mexico for wind resource assessment, highlighting lower performance in regions characterised by complex coastal topography. Asano and Kusaka (2021) show how simulations with the WRF model can be applied to support agricultural practices, evaluating the damaging impact of foehn wind, a typical and well-known mountain phenomenon, on rice crops in Yamagata Prefecture (Japan). Another typical mountain phenomenon, that is, dynamic airflow channelling, is analysed by Sato and Kusaka (2022) in the valley-like topography of the Kitakami Basin (Japan).…”

Future changes of the extreme high‐temperature events influenced by foehn winds in Niigata, Japan

“…Takane and Kusaka (2011) and Nishi and Kusaka (2019) showed that foehn winds were predominant during the historical ETEs (inferred from maximum temperature records) that occurred in the Kanto Plain, located on the Pacific side of Japan (Figure 1). ETEs occurring in the plains located in the Sea of Japan are also related to foehn winds (Asano & Kusaka, 2021; Ishizaki & Takayabu, 2009; Kusaka et al, 2021; Nishi et al, 2019; Nishi et al, 2022). Nishi et al (2019) showed that the nighttime ETE on 23 August 2018 in Niigata, which is the largest city on the Sea of Japan coast, was influenced by both foehn winds and urban heat‐island effects.…”