KOHSHIMA Shiro Faculty of Science, Tokyo University of Technology, Associate Professor, 理学部, 助教授 (60183802)
OSADA Kazuo Solar-Terrestrial Environment Laboratory, Nagoya University, Research Associate, 太陽地球環境研究所, 助手 (80252295)
|Budget Amount *help
¥7,800,000 (Direct Cost : ¥7,800,000)
Fiscal Year 1996 : ¥800,000 (Direct Cost : ¥800,000)
Fiscal Year 1995 : ¥7,000,000 (Direct Cost : ¥7,000,000)
Impurities on the snow surfaces would decrease the albedo and accordingly accelerate the rate of melting significantly through their aggregation, which is one of the most important roles, in particular of solid impurities such as mineral and biological particles. It is of great importance to observe their optical characteristics in detail, and to analyze quantitatively the relations between the dynamic abundance of impurities, their optical role in terms of energy budget and rate of snow melt.
In this study, first of all, the role of mineral dust has been examined experimentally. It was found that the impurities tend to aggregate, as the melting proceeds, and the albedo increases resulting in retarding the rate of melting. In other words, the surface dust has an effect of negative feed back in snow melt. In case for glacier ice, the surface runoff of melt water accelerated the effect. This effect has been successfully incorporated in a snow melt model. For biological dust (snow algae), the effect of reproduction, which is a function of abundance of water, light and nutrient, make the process very complex. The conservation law does not hold in this case, when we look at the biomass only. It was not possible, therefore, to incorporate the process in the snow melt model. It was found, however, that the biological particles can be a good indicator for identifying annual layrs, which is of great use in ice core analysis.