Oslo Science Conference, Oslo, Norway, June 8-12, 2010

Deterministic-stochastic modelling as a potential tool for the assessment of climate change impacts on hydrological regime in polar regions

Olga Semenova

The deterministic-stochastic approach can be used for effective quantifiable probabilistic evaluation of the effects of climate change on permafrost and runoff regimes. Here the deterministic model distinguish between the processes in permafrost landscapes with different soil, vegetation, and snow properties, while the stochastic model provide stochastic meteorological input and a framework to link global climate models in a changing environment with the land surface components. 
The Deterministic-Stochastic Modelling System (DSMS) developed in the State Hydrological Institute is applied. The DSMS consists of two elements: a deterministic model of runoff formation processes called “Hydrograph” and the Stochastic Model of Weather (SMW). SMW provides simulated meteorological input for the Hydrograph model (daily precipitation sequences, average daily temperatures, and relative humidity at different points within river basin) taking into account temporal and spatial correlations between meteorological elements and characteristics of their annual variability according to evaluated parameters or the climate scenarios.
The results of the DSMS application to the Lena River basin in retrospective mode will be presented. The assessment of the DSMS performance was done independently for the deterministic and the stochastic components. Using simulated runoff hydrographs, the probability distribution curves of daily flow, annual mean, maximum and minimum flows were obtained and compared with the observed ones. The results have shown that the output of such a modelling system is reliable in comparison to observational data.
The next step will be the application of the DSMS using IPCC climate change scenarios with particular emphasis to the change of the annual, seasonal and extreme runoff distribution from a probabilistic point of view.
permanent link to this abstract: http://hydrograph-model.ru/abstract.php?mode=external&id=17