People of central Asia totally depend on seasonal People of central Asia totally depend on seasonal snow and glacier melt water. Without snow and snow and glacier melt water. Without snow and

glaciers, central Asia will dry out.glaciers, central Asia will dry out.

Is Central Asia really exsiccated?Is Central Asia really exsiccated?Vladimir and Elena Aizen, Arzhan SurazakovVladimir and Elena Aizen, Arzhan Surazakov

University of IdahoUniversity of Idaho

• From ancient to modern irrigation systems• Agricultural and industrial expansion• Population grows

Objective: What is the past century climate and water resources changes in central Asia?

Data: Long-term observational data and assimilated remote sensing information. Aerial (1943), remote sensing data (Corona, Hexagon KH-9, Landsat, Aster, SRTM and MODIS – collection 4-5)

Methods: • Thiessen’s spatial averaging/polygon method to interpolate gaps in meteorological data.

- differences in averages for two thirty-year periods 1972-2002 &1942-1972 T-test at 20% for precipitation and 10 % for air temperature level

- linear trends for the same periods. Coefficients of determination, F tests at 80% for precipitation and 90% for air temperature level of significant

- acceleration in changes for the last thirty years is difference in trends- differences in standard deviations and coefficient variations two thirty-year

periods. • Geographically weighted regression (GWR) method for spatial interpolation of precipitation (P) and temperature (T) data. The optimal size of the kernel is 30 neighbors

• Imagery processing

Region area№ of stat.

Period Resol. Conclusion Authors

(Tien Shan200 to > 4000 m

110 1940-1991 monthlyTemp. +0.01C/yr

Prec.+1.2 mm /yr l<2000mAizen, et al., 1997

Central Asia35-50N 75-120E

32 1951-1990 summer At SE Mongolia & N China negative trend Yatagai & Yasunari,

1995

Tajikistan800-4000 m

4 1930-1991 yearTemp . +2.2C /60 yr and +0.4C HE

Preci. +0.05 to 0.25 mm/yr <1000 m+1.82to +5/37 >2000 m

Finaev, 1995

Central A sia plains and foothills

26 +50 1891-1991year

summer

Steady positive trend in air temperature. Decrease of total river runoff and increase in its variability for 1962-

91 comparing for 1931-60

Konovalov, 2003; Konovalov &Williams, 2005

Central Asia 68 - 3614 m

39- 45N 62-78E21 1879-2001 year

Temp. + 0.027 C /yr Giese et al., 2007

Northern China 9 1979–1999 Winter Successive droughts for 3 summers (1997-99) at northern China

Xu, 2001

Recent research on climate changes over the Central Asia

Caspian Sea

Aral Sea Balkhash

90°E

90°E

80°E

80°E

70°E

70°E

60°E

60°E50°E

50°N45°N

45°N40°N

40°N35°N

Caspian Sea

Aral SeaBalkhash

100°E

90°E

90°E

80°E

80°E

70°E

70°E

60°E

60°E50°E

55°N

50°N45°N

45°N40°N

40°N35°N

Altai-Sayan

Aral-Caspean deserts

Central Tien Shan

Eastern Pamir

Eastern Tien Shan

Inner Tien Shan

Issik Kul

Kazakhstan steppe

Mongolia

Northern Tien Shan

Tarim

Western Pamir

Western Tien Shan

264 Central Asian hydro-meteorological stations used for analysis

Number of stations by elevations

Main periods of observations 1942-1972and 1973-2003

Central Asia by climatic zones

Caspian Sea

Aral SeaBalkhash

90°E

90°E

80°E

80°E

70°E

70°E

60°E

60°E50°E

50°N45°N

45°N40°N

40°N

35°N

0 2.19

Caspian Sea

Aral Sea Balkhash

90°E

90°E

80°E

80°E

70°E

70°E

60°E

60°E50°E

50°N45°N

45°N40°N

40°N

35°N

0 1.89

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

A B

Caspian Sea

Aral Sea Balkhash

90°E

90°E

80°E

80°E

70°E

70°E

60°E

60°E50°E

50°N45°N

45°N40°N

40°N

35°N

-0.1 0 0.22

Caspian Sea

Aral Sea Balkhash

90°E

90°E

80°E

80°E

70°E

70°E

60°E

60°E50°E

50°N45°N

45°N40°N

40°N

35°N

-0.1 0 0.5

Acceleration in changes of annual (A) and summer (B) air temperature for the last 30 years (Δ = SLOPE1973-2003 – SLOPE1942-1972)A B

Caspian Sea

Aral Sea Balkhash

90°E

90°E

80°E

80°E

70°E

70°E

60°E

60°E50°E

50°N45°N

45°N40°N

40°N

35°N

-120 0 54

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

Caspian Sea

Aral Sea Balkhash

90°E

90°E

80°E

80°E

70°E

70°E

60°E

60°E50°E

50°N45°N

45°N40°N

40°N

35°N

-40 0 42

Caspian Sea

Aral Sea Balkhash

90°E

90°E

80°E

80°E

70°E

70°E

60°E

60°E50°E

50°N45°N

45°N40°N

40°N

35°N

-67 0 56

Differences in 30-year averages of winter (A) and summer (B) precipitation (Δ = AVE1972-2002 – AVE1942-1972)

A B

Caspian Sea

Aral Sea Balkhash

90°E

90°E

80°E

80°E

70°E

70°E

60°E

60°E50°E

50°N45°N

45°N40°N

40°N

35°N

-8.5 0 9.2

Acceleration in changes of annual precipitation Δ = SLOPE1972-2002 – SLOPE1942-1972)

Accelerating changes by region of precipitation for the last 30 years compared to the previous 30 years , Acc = Sl1972-2005 - Sl1942-1972, mm

Accelerating altitudinal changes of precipitation for the last 30 years compared to the previous 30 years , Acc = Sl1972-2005 - Sl1942-1972, mm

Annual and decadal total particle concentration

0.0E+00

1.0E+05

2.0E+05

3.0E+05

4.0E+05

1910192019301940195019601970198019902000

Year

Co

nc (

nu

m/m

L)

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.

Tien Shan, number of days with snow 2000-2001

Tien Shan, number of days with snow 2006-2007

The seasonal snow covered area in Tien Shan decreased by 15% approximately 120 000 km2

Snow covered areas by 1,000m isohyps over the Tien Shan for the last twenty years reconstructed by surface observational, AVHRR and MODIS data

0

20

40

60

80

snow cover, %

1987 2000 2001 2002 2003 2004 2005 2006 2007199919981997199619951994199319921991199019891988

ten days AVHRR data calibrated with surface observational data eight days 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.

Glacier area change

- 3.5 % - 14.1%

K A Z A K H S T A N

C H I N A0 50 150 km

1,617 km2 (-10.1%) glacier area reduction during the last thirty years in Tien Shan

Aksiirak glacierized massif182 glaciers; 427 km2 glacierized area (aerial photogrammetry 1943)

19431977182 glaciers; 406.8 km2 glacierized area; 4.2% area reduction (aerial photogrammetry 1943/1977)

2003

178 glaciers; 371.6 km2 glacierized area; 8.7% area reduction(aerial photogrammetry 1977/ASTER 2003)

Inner Tien Shan areaInner Tien Shan area

2003 2002199519771956194318691800

Petrov Glacier

Conclusion

• Statistically significant difference in means of annual and seasonal precipitation and air temperature for two 30-year periods was observed at more than 73 (precipitation) and /93% (air temperature) of 264 stations

• The last 30-years average precipitation has decreased on 0.1% of average compared with previous 30-years

• The last thirty year deficit of precipitation income was -62 km3 that is about 6 % from total 1,048 km3 volume Tien Shan glaciers

• The most significant deficit in precipitation income observed at the alpine regions and Kazakhstan steppes during summer season

• Acceleration in decrease of precipitation for the last 30 years for all central Asia

• Increased precipitation in winter at low altitudes, at Aral-Caspian and Tarim basin deserts, western and even Eastern Pamir

• Increased annual air temperatures for the last 30 years on 0.68°C by increased summer air temperatures

• Total central river runoff have decreased on 4% in all central Asia

• Snow covered areas shrunk by 15% and glacier covered area by 10% over the last 30 years