Characteristics of Local Wind “Matsubori Kaze” and Its Wind Damage

Abstract

The strong easterly wind formed in the valley of the Aso somma is known as “Matsubori Kaze”. This local wind causes wind damage in this region. Therefore, the characteristics of this local wind and its wind damage to barley were investigated. Meteorological observations were carried out at Aso region from April 9, 1999 to May 31, 2000 and from April 1 to May 31, 2001, and the damage to barley was investigated at harvest in 1999, 2000 and 2001.
The airflow over mountains is formed in Aso somma under conditions of stable stratification and the prevailing southeastly wind speed was over 10m/s at the level of about 850hPa. The airflow over mountains converges in the valley of Aso somma, creating a strong wind with a speed over 10m/s. It is thought that this strong wind is “Matsubori Kaze”.
“Matsubori Kaze” removes the awn of barley, thus obstructing the ripening of the grain by eliminating photosynthesis by the awn. In 1999 “Matsubori Kaze” blew at early stage of ripening removing the awn of barley. Thousand grain weight of barley decreases by 10 to 20% when compared with the leeward zone where there was no wind damage in 1999. “Matsubori Kaze” negatively affects barley in this region.