Role of Glaciers and Snow Cover in Rivers Discharge and LCLU Changes over Central Asia and South Siberia
Vladimir
Aizen, University of Idaho, aizen@uidaho.edu
(Presenting)
Elena
Aizen, University of Idaho, eaizen@uidaho.edu
Arzhan
Surazakov, University of Idaho, asurazakov@vandals.uidaho.edu
Roland
Geerken, Yale University, roland .geerken@yale.edu
Genadiy
Nosenko, Institute of Geography, RAS, Russia, gnosenko@mail.ru
Stanislav
Nikitin, Tomsk State University, Russia, santvp@mail.tsu.ru
Alexander
Finaev, Institute of Water Problem, Hydropower and Ecology, Tajikistan, foker@list.ru
Valeriy
Kuzmichenok, Institute of Water Resources and Hydropower, Kyrgyzstan, iwp@istc.kg
The central Asia glaciers (Altai, Tien Shan and Pamir) cover 30,627km2 and comprise approximately 3,133km3 of fresh water. Seasonal snow cover and glaciers of central Asia are supplying water and generate river flow vital not only for the millions of people living downstream, but also for forestry, agriculture, industry, and urban areas in adjacent lowlands. The human activity has been identified as contributing to land degradation.
The first results showed that Altai glaciers shrank by 7.2% for the last 60years, precipitation increased by 3.2mm yr-1. The main cause of glacier recession in Altai was the growth in spring/summer air temperatures (0.03oC yr-1). In Tien Shan glacier glaciers shrank by 10.1% during the last 30 years. The glacier recession increased by three times between 1977 and 2003 in comparison with 1943-1977. The duration of snow melt from the date of maximum snow cover to the date of it’s disappearance reduced by 30 days and was equal to 138 days between 1987-2007. The snow covered area in the Tien Shan decreased by 15%. Simulation of the current glacier state and forecast of potential impact of climate change estimated that, an increase in air temperature of 1oC at ELA must be compensated by 100 mm increase in precipitation at the same altitude to maintain glaciers in their current state. An increase in mean air temperature of 4oC and precipitation by 1.1 times of the current level that is predicted for the 21st century may uplift ELA by 570m. The number of glaciers, glacier covered area, glacier volume, and glacier runoff are predicted to be 94%, 69%, 75%, and 75% of current values. The maximum glacier runoff may reach as much as 1.25 times current levels while the minimum will likely equal zero. While the Tien Shan glacier area decreases continuously, at the last decade the annual river discharge is growing mainly due to precipitation increase. In Pamir at elevations over 3000m annual precipitation increased by 8.1mm yr-1 for the last 17 years.
Increasing river runoff and intense irrigation caused wide-spread salinization processes, leading up to 50% losses in arable lands in central Asia.
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