Long-term modelling of runoff formation processes at remote mountainous
permafrost basin using historical data of short-term special
observations (Suntar-Khayata Ridge, Eastern Siberia).
Abstract
The study investigates the possibility to parameterize a hydrological
model for remote high-altitude permafrost basin based on the data of
historical short-term observations conducted in 1957-1959 at the
Suntar-Khayata research station (Eastern Siberia) and simulate the
changes of runoff observed in recent decades in the region. The
Hydrograph model is applied as it has the advantage of using observed
physical properties of landscapes as its parameters. The developed
parametrization of the goltsy landscape is verified by the results of
simulations of variable states of snow and frozen ground. Continuous
simulations of streamflow with daily time step are conducted for the
period of 1957-2012 at the Suntar River basin (area 7680 km2, altitude
828-2794 m) with average and median values of Nash-Sutcliff criteria
reaching 0.58 and 0.67 respectively. The results of simulations have
shown that the largest part of runoff (about 70%) is formed in the
high-altitude area which takes only 44% of the Suntar River basin area.
Simulated series of streamflow reproduce the patterns of recently
observed changes, including the increase of low flow, by magnitude of
trends and their change period, suggesting that the increase of the
increase of liquid precipitation share in autumn months due to air
temperature rise can be important factor of streamflow changes in the
region. The data presented in the paper are unique for the vast
mountainous parts of North-Eastern Eurasia which play important role in
general climate circulation. The results indicate that if the assessment
of hydrological model parameters is based on observation data instead of
calibration, the models can be used in the tasks of studying the
response of river basins to climate change with more confidence.