Presentation on theme: "Role of High Mountains in Climate and Water Cycle over Dry Regions of Central Asia Vladimir Aizen University of Idaho, U.S.A."— Presentation transcript:
Role of High Mountains in Climate and Water Cycle over Dry Regions of Central Asia Vladimir Aizen University of Idaho, U.S.A.
Amur Yenisey Ob Sirdarya Amydarya Tarim Ili > 1,000,000km 2 mountainous area over 1,000 m 45,000 km 2 glacierized area ~ 80,000 km 2 frozen ground area > 3,000 km 3 fresh water stored in the glaciers > 200 million water consumers Source: Dolgushin, 1989; Gorbunov, 2001; Kotlyakov, 1996 > 1,000,000km 2 mountainous area over 1,000 m 45,000 km 2 glacierized area ~ 80,000 km 2 frozen ground area > 3,000 km 3 fresh water stored in the glaciers > 200 million water consumers Source: Dolgushin, 1989; Gorbunov, 2001; Kotlyakov, 1996 Karakorum 80% freshwater originated in mountains 40% seasonal snow 25% from glaciers ~5% from permafrost
MONGOLIA C H I N A KAZAKHSTAN AFGHANISTAN TURKMENISTAN UZBEKISTAN KYRGYZSTAN TAJIKISTAN No glacier – no life in the central Asia dry lands!
Источник: Фото Л. Браун
winterspring summer autumn
Altai Tien Shan Pamir Takla Makan G o b i Kara Kum Kizil Kum Myuyn Kum Dasht-e Margow Qaidam Total annual number of dust storms observed at ten central Asian stations. Days Source: Weihong Qian, et al., JC, 2001
The increase in air temperature can be one of the main factor of dry land and hydrological cycle instability Source: Carbon Dioxide Information Analysis Center (CDIAC); Lugina et al Air temperature, C
Ann air temperature, o C Ann precipitation, mm Sibrian Altai ( , 12 stations): air temperature increased at low elevations more (0.3 o C yr -1 ) than at high elevations (0.01 o C yr -1 ). Precipitation decreased at low elevations and increased at high elevations (3.8mm yr -1 ), notably in spring months. Tien Shan ( , 18 stations): air temperature increased at low elevations (0.02 o C yr-1) more than at high elevations. Precipitation have insignificant increasing trend over the entire Tien Shan. Pamir ( , 4 stations): air temperature increased at low elevations (0.03 o C yr -1 ) and 0.01 o C yr -1 at high elevations over 3,000m a.s.l. Precipitation increased at low elevations (0.08mm yr -1 ) and particularly at high elevations of western and central Pamir (8.1mm yr -1 ), notably in winter months
Snow covered areas by 1,000m isohyps over the Tien Shan for the last twenty years reconstructed by surface observational, AVHRR and MODIS data Duration of snow melt from the date of maximum snow cover to date of its disappearance reduced on 30 days during the last twenty years, equal 138 days in Snow melt 30 days faster then 20 years ago. The decrease of snow cover is not linear process. Further decrease of snow covered areas may be accelerated due to reduced snow covered area and consequently lesser of heat input necessary for snow melt. ten days AVHRR data calibrated with surface observational data eight days MODIS data
Interaction between the general circulation of the atmosphere, the meridional gradient of global air temperature, and snow covered area in Eurasia A B
Altai, Tien Shan, Pamir, Karakoram and Kunlun are the major mountain ridges of dry central Asia that maintain high volume of snow and ice, the main sources of water in this region 5.2% 11.1% 4.2% 17.1% 11% 19.2%
Aksiirak glacierized massif 182 glaciers 427 km 2 glacierized area (aerial photogrammetry 1943) glaciers km 2 glacierized area 4.2% area reduction (aerial photogrammetry 1943/1977) glaciers km 2 glacierized area 8.7% area reduction (aerial photogrammetry 1977/ASTER 2003) Akshiirak glacierized massif, Central Tien Shan Source: Aizen, and others, AG, 2006
~ Petrova Glacier termini, Akshiirak glacierized massif (65.33 km 2, from 1869 to 2007 this glacier retreated on 3 km) Petrova Glacier termini, Akshiirak glacierized massif (65.33 km 2, from 1869 to 2007 this glacier retreated on 3 km) Source: Aizen, and others, AG, 2006
Akshiirak glacial surface change between 1977 and 2000 evaluated by aerial photogrammetry and SRTM data Source: Aizen, et al., Annals of Glaciology, m decrease in glacier surface 9.6 km 3 ice-volume reduction since 1943
The Tien Shan High Mountains experimental Lidar station. Deviations from long-term average (background) of reverse aerosol scattering coefficients in layer of Stratospheric Aerosol (15-30 km). The background value over central Asia is 1.56 · Altai Kuwait India Pakistan Lop Nor Aerosols: impact snow and glacier surface albedo change intensity of snow/ice melt and near surface heat exchange contaminate atmosphere and water quality increase or decrease global air temperature
Source: Aizen, Marchenko, NSF annual report, 2000 Measured mean annual ground temperatures at different depths at the Tien Shan meteorological station (3614 m). Permafrost: impacts In mountainous areas, thawing permafrost increases risk of landslides and rock falls and has impacts on infrastructure. Permafrost in Tien Shan has degraded over the past 40 years and is projected to decrease by 20-30% in this century.
glaciers: impacts Shrinkage of glaciers leads to ice instability and formation of ice and debris dams, resulting in more flooding, debris flows ice and avalanches.
lakes: impact Merzbacher Lake Issik Kul LakeAral Lake In river basins with small glacierized areas, increase of glacier melt has already led to a decline in river discharge that partly explain the wastage of large Central Asian lakes. more than one-third of glacial lakes with surface areas between 1 and 5 km 2 have disappeared in central Asia
Earlier, synchronous snow and glacier melt changes regime of river runoff causing hydrological instability, spring cloudburst flooding, and protracted period of glacier melt, which temporary increase river discharge but facilitate quick glacier recession. snow peak in mid 1980th glacier melt glacier and snow melt peak since mid 1980th rivers: impact
Alpine climate and environmental changes impact and consequences - earlier disappearance of seasonal snow cover, shrunk of the glaciers, and alpine permafrost (particularly from the middle of 1970th) - increase evaporation accelerate desertification at lowlands intensify of dust storms and aerosol loading to atmosphere increasing near surface heat balance and regional and global air temperatures - extend snow and glacier ablation period and land-soil instability causes change frequency and magnitude of natural hazards - change central Asian hydrological cycle - lack of surface and ground water decrease water quality causes salinization and decline of agricultural production - increase of mortality rate and people migration.
We need more research and information high-elevation meteorological monitoring integrative ice-core ground- based and remote sensing data analysis during the last 30 to 50 years high-elevation atmospheric dust-aerosol monitoring alpine ice-core paleo-climate and environmental analysis atmosphere - land surface (alpine terrain) interactive analysis and modeling