[M-IS11] Mountain Science

[MIS11-P04] Formation of cold air lake and cold air drainage in the Mumaya Basin, Central Japan

*Akihiko SASAKI¹, Motoshi Nishimura², Toru Awazawa^3,4, Keisuke Suzuki^3,5 (1.Department of Geography and Environmental Studies, Kokushikan University, 2.National Institute of Polar Research, 3.Research Center for Mountain Environment, Shinshu University, 4.W Summit Co., Ltd., 5.Omachi Alpine Museum)

Keywords:cold air lake, cold air drainage, meteorological observation, radiation cooling, intermontane basin

The Mumaya area in Takayama City, northern Gifu Prefecture, is known as an area where low temperatures are often recorded in the Chubu region. The Mumaya Basin is a small basin of about 0.5 km², along the Mumaya River. The basin located at an altitude of 1000-1020 m and surrounded by hills about 300 m in relative height. The daily minimum temperature of lower than -20°C have been recorded in the past 45 years. These low winter temperatures are thought to be due to the accumulation of cold air from radiation cooling at the basin floor, but also from cold air flows from the surrounding hills. Cold air outflow along the Mumaya River valley after the formation of the cold air lake is also considered. The presenters have installed meteorological stations at the basin bottom of Mumaya to observe air temperature and humidity, wind direction and speed, radiation budget, atmospheric pressure and precipitation, and installed thermometers along the Mumaya River and around the basin to observe air temperature. This presentation will discuss the formation process of cold lakes in the Mumaya Basin using these meteorological data.