ИСТИНА

The ECOMAG regional hydrological model was setup to assess possible impact of climate change on the hydrological regime of two great Arctic drainage basins: Lena and MacKenzie. We firstly assessed the reliability of the hydrological model to reproduce the historical streamflow series and analyse the hydrological projections from the climate change scenarios. The impacts were assessed in three 30-year periods: early- (2006-2035), mid- (2036-2065) and end-century (2070-2099) using an ensemble of five GCMs and four Representative Concentration Pathways (RCP) scenarios. Extreme hydrological characteristics (specified as runoff volume above the assigned streamflow thresholds) were derived from the simulated streamflow series. Then we assessed the extreme characteristics’ uncertainty, which is caused by the GCM’s and RCP’s variabilities. We finally estimated signal-to-noise ratio in order to separate the deterministic signal from the stochastic noise cased by the scenario uncertainty. We found that the uncertainty interval becomes larger and the signal becomes undetectable against the background of the noise, when the projection’s time horizon increases and the assigned streamflow threshold rises. The present work has been carried out within the framework of the Panta Rhei Research Initiative of the International Association of Hydrological Sciences (IAHS)