Characteristics of runoffs in subarctic river basins; a comparison between Alaska and Hokkaido
Dates
Year
2013
Citation
Chikita, Kazuhisa A., 2013, Characteristics of runoffs in subarctic river basins; a comparison between Alaska and Hokkaido: Journal of Japanese Association of Hydrological Sciences, v. 42, no. 3, p. 131-146.
Summary
According to the Koppen -Geiger climate classification, Hokkaido and central to southern Alaska are located at near southrn and northern borders of the subarctic region, respectively. River basins in Hokkaido and Alaska receive similar climatological and hydrological conditions of summer to autumn rainfall, winter snowfall and spring snowmelt. Here, hydrological characteristics of the Saromabetsu river basin (area, 277.0 km super(2)) and the Oikamanai river basin (area, 62.0 km super(2)) in Hokkaido are compared with those of the Tanana river basin (area, 6.6310 super(4) km super(2)) in Alaska. Hourly time series of river discharge, Q, and suspended sediment concentration, C, in runoff events offers the relationship between Q and C [...]
Summary
According to the Koppen -Geiger climate classification, Hokkaido and central to southern Alaska are located at near southrn and northern borders of the subarctic region, respectively. River basins in Hokkaido and Alaska receive similar climatological and hydrological conditions of summer to autumn rainfall, winter snowfall and spring snowmelt. Here, hydrological characteristics of the Saromabetsu river basin (area, 277.0 km super(2)) and the Oikamanai river basin (area, 62.0 km super(2)) in Hokkaido are compared with those of the Tanana river basin (area, 6.6310 super(4) km super(2)) in Alaska. Hourly time series of river discharge, Q, and suspended sediment concentration, C, in runoff events offers the relationship between Q and C for the three river basins. The C to Q relation for the Tanana and Saromabetsu rivers exhibited the clockwise hysteresis, while that for the Oikamanai river basin furnishes the counterclockwise hysteresis during rainfall runoffs. The counterclockwise loop suggests that the throughflow under the basin slope erodes and transports soil particles. The runoff analysis was conducted by the tank model to simulate daily discharge time series of the Saromabetsu and Tanana rivers in snowmelt and glacier-melt seasons, respectively. Optimizing the tank parameters for discharge time series of a certain year, the simulations for snowmelt and glacier-melt runoffs in the other years were reasonable with the root mean square error at 7.6 to 17 % of observed discharge and the Nash-Sutcliffe efficiency coefficient at 0.45 to 0.97. The high applicability of the tank model is probably caused by the consideration of water storage in snow and glaciers, and by each similar hydrological condition of initial soil water content and initial englacial water storage in the snowmelt and glacier-melt seasons.
