Figure 1. Map of the study region. (a) Location of the Tyrma region. Permafrost boundary was drawn with reference to Shamov et al. (2014). (b) Elevation map of the Tyrma region. Areas enclosed by colored lines and numbers L1–L5 shows the catchment areas and the sampling sites of large river waters. (c) Detailed elevation map for the sampled small watersheds. Areas enclosed by black lines and numbers 1–19 show the catchment areas and the sampling sites of small river waters. Maps (b) and (c) were created by the authors using Quantum GIS based on a 30 m resolution digital elevation model (DEM) provided by Japan Aerospace Exploration Agency (JAXA).