Caspian Sea water level fluctuation: comparison between ground Measurement and altimetry M Bolgov R Mammedov J-F Crétaux M. Bergé-Nguyen A. Kouraev
Destruction of a coastal zone in northern coast of Azerbaijan as a result of rise of a sea level.
Caspian Sea level fluctuation problem Peculiarities of the variability of the Caspian Sea level The variability of the Caspian Sea level can be classified on cycles: • Geological period, • Historical period, • Yearly change, • Seasonal change.
Variability of the Caspian Sea level for historical period: 1-Historical period, 2-Average tendency its, 3-Frequency of repetition, 4-Average tendency, 5-Level maximum, 6-Level minimum.
Annual levels of the Caspian Sea measured in the Baku post. 1-measured level, 2- tendencies of changing. In the framework seasonal changing level is shown.
Reasons for changes in sea level Geological factors Anthropogenic factors Hydroclimatic factors
Water mass balance estimation The balance of water in the Caspian Sea is determined by the following contributory factors: 1) surface river flow into the sea; 2) precipitation over the surface of the sea; 3) underground flow into the sea; 4) evaporation from the surface of the sea; 5) outflow into the gulf of Kara-Bogaz-Gol. The first three factors constitute additions to and the last two, subtractions from, the water stock of the Caspian DV/dt = (Runoffrivers - RunoffKBG) + (Gi-Go) +(P-E)
Altimetry on the Caspian sea and Kara Bogaz Gol Gulf • This concerns three main components: • Calculation of decadal Caspian Sea and KBG level variation and comparison with in-situ measurements • Estimation of water mass balance of each water bodies, based on coupled altimetry-climatological data • Study of ice regime in the north of Caspian sea from combination of active (altimetry) and passive (radiometry) microwave data
Study of CSL from altimetry + Digital Bathymetry Map
Global agreement with remaining local discrepancies (70 mm in 1995) Errors in altimetry ~15 mm/yr Possible uncertainty in the global lake level deduced from terrestrial gauges to investigate
4 December 1972 29 September 1987 Change of the area of gulf Gara-Bogaz-Gol Mamedov (1996) presents the following relationship (attributed to Sheremetievskoi): where, QKBG = annual inflow to the KBG (km3), H = average annual sea level at Baku (cm), QC = annual inflow to the Caspian Sea (km3).
+ DV/dt = Runoff (Caspi->KBG) – (E-P)*Surface(t)
Geographycal distribution of annual CSL variation deduced from 10 years (1993-2002) Of Topex / Poseidon data and average seasonal variation Annual Amplitude (m)