Changes in The Climatic Regime on The Caspian See Regions over The Past Century

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Changes in The Climatic Regime on The Caspian See
Regions over The Past Century Nikolay
Sidorenkov1 and Valentina Shveikina2
1Hydrometcentr of Russia, Bolshoi Predtechenskii
per. 11-13, Moscow, 123458, Russia
e-mail sidorenkov_at_mecom.ru
2Water Problems Institute of the Russian Academy
of Sciences
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ABSTRACT A unique database of the
Hydrometcentr of Russia is used to determine
characteristic periods of changes in the air
temperature, annual sums of precipitation, and
cloudiness over the Caspian Sea region. The
analysis of the above data series using the
integrated (cumulative) curves showed good
agreement between fluctuations of meteorological
elements and the atmospheric circulation epochs.
It is shown that the correlation between
these epochs and the Earth rotation regimes may
be used for the assessment of the state and
tendencies of change in the climatic regime in
the Caspian Sea basin.
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Figure 1. Changes in mean annual air temperature
(top) and annual sums of precipitation (bottom
curve), both averaged over the area of the Volga
basin
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Figure 2. Integrated (cumulative) sums of
anomalies of circulation form frequency C'
(bottom), annual sum of precipitation R/
(middle), and mean annual air temperature T'
(top)
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Figure 3. Synchronous changes in the length of
day (solid curve) and the integrated (cumulative)
sum of anomalies of circulation form frequency C'
(dashed curve)
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Figure 4. Changes in the Caspian sea level in
1891-2005
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Figure 5. Changes in the Caspian sea level (top)
and the cumulative sum D of the discharge water
through the Volgograd dam (after calculation
(D/2-100) km3) (bottom) in 1891-2005  
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Conclusion  It is found that the sea level
rise, started in 1978, was due to the circulation
epoch change in 1972. The new epoch was
remarkable for a low frequency of the circulation
form C and a high frequency of the form E. Onset
of this epoch favoured to an increase in R, O,
and T and decrease in the wind speed. Due to
this, the runoff of the Volga increased and the
evaporation from the sea surface decreased, both
causing the sea level rise. A delay in the sea
level response to the changed circulation regime
is due to the process inertia. The climatic
epoch that began in 1973 will probably end in the
nearest years, and a new climatic epoch will
begin. The climate change and the subsequent
change of the Caspian Sea water balance sign are
expected in 20073 years. The sea level rise will
last up to 20103 years and after that it will
start to drop up to 2045 5 years.