Early work on the
water balance of the Caspian Sea was based on annual water balance models. The models
developed in these previous studies reproduce water levels extremely well, but since any
measures to mitigate sea level rise will be operated seasonally, recent studies have
concentrated on modelling the water balance of the sea on a monthly basis.
The new water balance model has four basic options:
to compute a water balance closure error assuming that all
components of the water balance have been estimated by other means;
to compute evaporative losses as the dependant variable in the
balance;
to compute sea levels, given a set of inputs of inflow,
evaporation and precipitation on the sea, and a sink relationship for the Kara-Bogaz-Gol;
to compute inflows to the Kara-Bogaz-Gol
Results
It is estimated that half the recent changes detected in the water balance of
Caspian Sea region may be attributable to decreasing rates of evaporation. It seems that
there may be some warming of the temperature in the southern part of the sea and a cooling
over the northern region but these changes amount to only less than half a degree in the
summer. Generally, there is some overall warming in the winter.
Reports of increased cloud cover over the sea have not been
confirmed and there is no evidence for this being responsible for decreasing sea
evaporation over the last 30 years.
Mean monthly inflows to the Caspian Sea as modelled
Implied sea evaporation from water balance
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