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Is Central Asia really exsiccated? Vladimir and Elena Aizen, Arzhan Surazakov University of Idaho. People of central Asia totally depend on seasonal snow and glacier melt water. Without snow and glaciers, central Asia will dry out. From ancient to modern irrigation systems
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Vladimir and Elena Aizen, ArzhanSurazakov
University of Idaho
People of central Asia totally depend on seasonal snow and glacier melt water. Without snow and glaciers, central Asia will dry out.
Objective: What is the past century climate and water resources changes in
Central Asia by climatic zones
Number of stations by elevations
Main periods of observations 1942-1972
Differences in 30-year averages of annual (A) and summer (B) air temperature
(Δ = AVE1973-2003 – AVE1942-1972)
Average weighted differences between annual, annual-maximum & summer means temperatures (1973-2003 and 1942-1972) for climatic regions
Average weighted differences annual, annual-maximum and summer means of air temperatures (1973-2003 and 1942-1972) for altitudinal belts
Acceleration in changes of annual (A) and summer (B) air temperature for the last 30 years
(Δ = SLOPE1973-2003 – SLOPE1942-1972)
Differences in 30-year averages of annual precipitation (Δ = AVE1973-2003 – AVE1942-1972)
(A) altitudinal distribution of central Asia areas (S, km2), (B) average weighted differences in annual precipitation for the periods from 1973- 2003 and 1942-72 (Δ, km3 )
Altitudinal distribution of average weighted differences of annual precipitation for the periods from 1973- 2003 and 1942-72(b) (Δ, km3) by climatic regions
(Δ = AVE1972-2002 – AVE1942-1972)
Acceleration in changes of annual precipitation Δ = SLOPE1972-2002 – SLOPE1942-1972)
Accelerating altitudinal changes of precipitation for the last 30 years compared to the previous 30 years , Acc = Sl1972-2005 - Sl1942-1972, mm
Accelerating changes by region of precipitation for the last 30 years compared to the previous 30 years , Acc = Sl1972-2005 - Sl1942-1972, mm
Overall decadal trends show the high dust loading for the 1960’s and 70’s, with maximum dust loading apparent for the 30’s and that is in accordance with results from 154 Chinese stations on maximum frequency of dust weather for the mid-1960’s (Qian et al;Sun et al., 2002) and the lowest in the 90’s to be one-fifth that of the 60’s.
The seasonal snow covered area in Tien Shan decreased by 15%
approximately 120 000 km2
Tien Shan, number of days with snow 2006-2007
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 it’s disappearance reduced on 30 days during the last twenty years, equal 138 days in 2007. Snow melt 30 days faster then 20 years ago. The decrease of snow cover is not linear process.
ten days AVHRR data calibrated with surface observational data
eight days MODIS data
1,617 km2 (-10.1%) glacier area reduction during the last thirty years in Tien Shan
K A Z A K H S T A N
C H I N A
Aksiirak glacierized massif
182 glaciers; 427 km2 glacierized area (aerial photogrammetry 1943)
182 glaciers; 406.8 km2 glacierized area; 4.2% area reduction
(aerial photogrammetry 1943/1977)
178 glaciers; 371.6 km2 glacierized area; 8.7% area reduction
(aerial photogrammetry 1977/ASTER 2003)