FLOODPLAIN TALIK WIDTHS IN RELATION TO RIVER CATCHMENT AREAS AND CHANNEL TYPES
V.M. Mikhailov
North-Eastern Permafrost Research Station, Portovaya str. 16, Magadan, 685000, Russia
Keywords: permafrost, floodplain taliks, talik width, river catchment areas, river channel types, remote decryption methods
Abstract
Data on the width of floodplain taliks in river valleys of the mountainous areas of the northeastern part of Russia and in some adjacent areas of the Far East were gathered and organized. The investigated region extends from the Arctic coast to the southern limits of the continuous permafrost area. To assess the talik width, the satellite images (possessing high resolution) of Google Earth and previously established landscape features were used. The catchment areas at downstream ends of the chosen 340 representative river sections varied from less than 10 to more than 200 000 km2, talik widths - from 41 to 4100 m. The rivers were subdivided into 4 channel types according to the degree of its branching based on the previous studies confirming that the floodplain taliks were formed only by braided rivers on coarse-grained alluvium. The studied sites are generally evenly distributed both over the territory and according to the selected channel types. The changes in talik widths from marginal coastal to the central continental basins in relation to the river types are discussed in this paper. The parameters of the empirical power-law dependence of the talik width on the catchment area of the river are calculated. The obtained results assess a variation of the melting zone width within a given river catchment area and determine the most probable minimum value of this parameter. In future, the approaches used, in combination with the field research, will contribute to the improvement of remote decryption methods.
|