Shigeki Murakami

High correlation between winter precipitation and air temperature in heavy-snowfall areas in Japan

Abstract Long-term data of winter air temperature and precipitation were analyzed and the correlation between them investigated in order to identify the factors influencing snow reduction during the recent warmer winters in the heavy-snowfall areas in Japan. A high negative correlation between winter precipitation and air temperature was identified in the heavy-snowfall areas on the Sea of Japan side in the center of the main island (Honshu). It was confirmed that precipitation is mainly caused by cold winter monsoons, and thus correlates to a large extent with air temperature in these areas. The precipitation decrease can be considered an effective factor for the recent reduction in snow as well as the snowfall to precipitation ratio. This should be taken into account for a better prediction of snow reduction in relation to global warming.

Difference in snowmelt processes between an opening and three Japanese cedar stands

Abstract Snowmelt was measured on a daily basis for 17 days at the open site and 18 days at three Japanese cedar sites with canopy closure of 17.8% (cedar stand A), 5.2% (B) and 2.4% (C) in April. Measured daily snowmelt at each site was reproduced by heat-balance calculation with an accuracy of <±1 mm w.e. From 1st April to the date of snow disappearance net radiation accounted for 88.4, 43.0, 32.7 and 34.2% of total snowmelt energy at the open site, the cedar stands A, B and C, respectively. The ratio of sensible and latent heat to total snowmelt was 33.1–37.9 and 25.9–29.4%, respectively, at three cedar stands. The ratios of sensible and latent heat increased over time in accordance with the rise in temperature at all cedar sites. They became large on a daily basis when air temperature and/or wind speed were high. Wind speed is dependent on morphology around each site that also dictated snowmelt.