Distribution of Surface Features of Snow Cover in Mizuho Plateau

Studies have been made of surface features such as the sastrugi, the dune and the glazed surface which represent stages of deposition-erosion process of the snow surface of the ice sheet. A descriptive method is established on the surface features and surface conditions from a standpoint of these stages of genetic process. Surface features are genetically classified into three categories; depositional form, erosional form, and long-term hiatus form which is widely distributed as a glazed surface and is related closely to the absence of annual layers. The present paper describes the first attempt to discuss the characteristics of these surface features and their significance in the surface condition and snow stratigraphy. Prevailing wind systems of Mizuho Plateau related to erosion and deposition processes are analyzed from the directional aspect of the surface features. It is found from the analysis that the one- and two-wind systems are related to the depositional and erosional processes and that a variation of wind system can almost correspond to that of surface condition. Mizuho Plateau can be divided into four regions on the one hand on the basis of the regional characteristics of the surface condition which is related closely to the mass budget mechanism of each region. Mizuho Plateau can be divided, on the other hand, into three regions on the basis of the regional characteristics of the mass balance. It can be estimated that their boundaries exist at 1800m and 3000-3200m in elevation above sea level