5:15 PM - 7:15 PM
[MIS12-P13] An assessment of meteorological and snow environment in Northern Japanse Alps region based on the in-situ observation
Keywords:Mountainous region, Snow cover
In the cryosphere, a global warming effect is significant, particularly in the Japanese alpine region, which is located in the relatively warm temperate zone of the mid-latitudes. This region is one of the areas where the snow environment is highly variable, including the snowfall amount and snow covered period. Consequently, the implementation of meteorological and cryospheric observations in this region has revealed the effectiveness of assessing the impact of climate change on the cryosphere. The necessity for continuous environmental monitoring is now essential.This presentation will report on the actual conditions of the snow environment and the surface energy balance using in-situ meteorological observation data collected since 2014 in the Kamikochi area, which is located in the subalpine zone of the Japanese mountains.
An automatic weather station was installed at an elevation of 1490 m in the Kamikochi area of the Northern Japanese Alps, and observations were made of air temperature, relative humidity, wind direction and speed, air pressure, down/up-ward shortwave radiation, down/up-ward longwave radiation, and snow depth. In this study, September was defined as the start of the year, and hourly data from September 2015 to May 2023 was analysed.
The positive degree day (PDD [K day]) was calculated for the period from January to April after the 2015/16 season, and the average PDD was 163.3 (±77.0; 1σ). Statistically significant (greater than 1σ) years were 2016, 2022, and 2023, while 2017, 2019, and 2020 were small.The snow covered period was also calculated in the same way, and the average was identified as 162.6 (±21.1) days. The snow covered period in 2018/19 winter was found to be statistically significantly longer, at 207 days, while the period in 2022/23 winter exhibited a low PDD, with a snow cover period of 140 days. The findings indicated that the snow covered period was comparatively short in the 2022/23 winter season, characterised by a high PDD, and prolonged in the 2018/19 winter season, marked by a low PDD. This observation suggests the presence of a negative correlation between the PDD and the snow cover period.
In the temperate cryosphere, even minor fluctuations in temperature can exert substantial influence on the snow environment. In the future, it will be important to analyse the relationship between temperature, surface energy balance, and snowmelt amount in more detail in order to understand the actual state of environmental change in the temperate cryosphere.
An automatic weather station was installed at an elevation of 1490 m in the Kamikochi area of the Northern Japanese Alps, and observations were made of air temperature, relative humidity, wind direction and speed, air pressure, down/up-ward shortwave radiation, down/up-ward longwave radiation, and snow depth. In this study, September was defined as the start of the year, and hourly data from September 2015 to May 2023 was analysed.
The positive degree day (PDD [K day]) was calculated for the period from January to April after the 2015/16 season, and the average PDD was 163.3 (±77.0; 1σ). Statistically significant (greater than 1σ) years were 2016, 2022, and 2023, while 2017, 2019, and 2020 were small.The snow covered period was also calculated in the same way, and the average was identified as 162.6 (±21.1) days. The snow covered period in 2018/19 winter was found to be statistically significantly longer, at 207 days, while the period in 2022/23 winter exhibited a low PDD, with a snow cover period of 140 days. The findings indicated that the snow covered period was comparatively short in the 2022/23 winter season, characterised by a high PDD, and prolonged in the 2018/19 winter season, marked by a low PDD. This observation suggests the presence of a negative correlation between the PDD and the snow cover period.
In the temperate cryosphere, even minor fluctuations in temperature can exert substantial influence on the snow environment. In the future, it will be important to analyse the relationship between temperature, surface energy balance, and snowmelt amount in more detail in order to understand the actual state of environmental change in the temperate cryosphere.