Modeling Long-Term Dynamics of River Flow in the Lena River Basin Based on a Distributed Conceptual Runoff Model

A new version of a conceptual climate model of river runoff was used to calculate daily and monthly hydrographs for the Lena R. basin with the use of MERRA reanalysis data and data on runoff from R-ArcticNet archive over a 32-year period (1980–2011). The optimization of model parameters and corrections to precipitation allowed the authors to obtain a good quality of the calculated runoff hydrographs and to reveal a trend in the long-term runoff dynamics over the historical period since 1985 to 2011. The period 1985–2011 shows an abrupt increase in the surface air temperature, an increase in precipitation in the Arctic region since the mid-1980s, in particular, in the Lena River basin. The climate changes have led to changes in the hydrological regime of the river basin, and the question of assessing the long-term dynamics of water discharges over this period, in particular, using the conceptual model, gains in importance.