تحليل سري زماني تراز آب درياي خزر با استفاده از داده هاي ماهواره هاي ارتفاع سنجي

Caspian Sea Level Time Series Analysis Using Satellites Altimetry Data

In this paper annual and small duration time series of Caspian Sea level fluctuations were modeled using Topex/Poseidon and Jason- 1 altimetry data by statistical methods from September 1992 to September 2007" To take into consideration crossover points of ground tracks, Caspian Sea covered with seven crossover passes. By means of principal component analysis technique, seven time series converted into one series. The Caspian sea level changes showed rising at the rate of +13.7 cm/yr between January 1993 and June 1995. However, by June 1995, the sea level started to drop abruptly, a trend was still observed in January 2001. From middle 1995 to March 1996 the rate of the Caspian Sea level drop was -34.0 cm/yr, and later it decreased a rate -29.3 cm/yr (June 1996- April 1997). From July 1998 to January 2001 rate of sea level decrease was-5.7 cm/yr. From January 2001 to March 2007 the sea level was rising at the rate of+5.5 cm/yr. With comparison of altimetry and level gages data in several stations we could observe high correlations. Correlation between altimetry and level gages data in Anzali, oil stokes station and mean of three stations in north part of Caspian Sea (Machachkala, Krasnovodsk and fort- Shevchenko) was 95.6,97.3 and 77.3 percent respectively.