V.I. Kravtsova

Lomonosov Moscow State University, Faculty of Geography, Moscow, Russia



The Aral Sea degradation is one of the strongest nature and ecological catastrophes of XX century. Regular space surveys and operative mapping have allowed to watch multiyear and seasonal changes of the Aral Sea area, formation of landscapes at a former sea bottom, some specific features, so as salt storms and wind-induced surges, and their impact to surrounded area. Through many years Laboratory of Aerospace Methods at Department of Cartography and Geoinformatics, MSU, conducts the space monitoring of the Aral Sea and surrounded territories. Multitemporal space images (from Salut, MKS orbital stations, Resurs-F, Resurs-O, Terra satellites) have been used for compiling of sea coast line retreat maps for the whole period of sea degradation. The map, which shows 14 positions of Aral coast line in 1957-2003, has allowed to account sea area degradation. The Aral Sea area in September 2003 was  19370 km2, that is 29% from its area in 1961.

Due to regular observations during a year from Terra and Aqua satellites, images have shown seasonal changes in sea area; comparison of seasonal area variations with radioaltimetry measurements (from Topex/Poseidon and Jason satellites) discovers their good connection.  Accurate mapping and determination of sea area shows some seasonal regularities: growth of area in spring and the beginning of summer and very fast decreasing in autumn. Fluctuations of sea area show also the influence of working regime of dam in former Berg strait to humidity of the Northern-Eastern bay of the Big Aral Sea. Some specific input of Amudarya River waters into the Aral Sea was seen at images 1998, 2003, 2004, 2006. Moreover salt storms and wind induced surges have been fixed at space images in 2003 and mapped. Seasonal dynamics of ecosystems of former sea bottom and surrounding territories has been investigated by mapping with multiseasonal imagery. A series of seasonal landscape change maps has shown that the basic processes of a former sea bottom territory seasonal dynamics are connected to a regime of moistening and salinization, drying of a ground and formation and then destruction of salt crusts on the edge of the narrowed humidified strips. These processes are characterised on a series of maps, which show the main regularities of former sea bottom functioning.

The work was created by  Programme of Leading Scientific Schools, Grant8306.2006.5