An investigation into abnormal dry-cold weather at the Kurobe headstream area of the Northern Japan Alps in August 2018: An example for estimating alpine-rocky desert climates

Abstract

In high mountainous areas, clouds appear and there is occasionally heavy rain, but it flows out and dries up quickly. Vegetation is rare due to the dry and cold conditions. In this paper, we introduce a method for estimating mountainous weather using the example of abnormally cold and dry conditions in the Northern Japan Alps. We conducted a survey on foot from 17-20 Aug 2018, and could reasonably evaluate the local weather or climate in the high mountains by chance observations and various data of characteristic midsummer weather. An inversion layer was observed at about 2000 m on 17-18 Aug at the Wajima Aerological Observatory, and a temperature gap was discerned at 1350-2330 m. On 17 Aug, cold, dry and rather strong winds of 13.5 m/s from the north affected the 1500-3000 m layer during the day, and the minimum air temperature at Tarodaira (2330 m) was -0.8°C at night. On 18 Aug, minimum air temperature was -2.8°C with cold-dry weak winds at Tarodaira, and -4.0°C with frost at an elevation of 1900-2300 m in the Yakushisawa basin of the Kurobe headstream area. An analysis of sensible local climate is introduced as the first step toward an estimation method for mountainous climates.