Changing Climate, Landcover and Water Resources in the Mountains of Central Asia over the last 60 years

Vladimir Aizen and Elena AizenUniversity of Idaho

• Population grows• Agricultural and industrial expansion/demand

1900 – 15M

2000 – 150M

Estimation of actual water resources of Central Asia and their changes for the last 60 years

- Climate- Seasonal snow cover- Glaciers

Water resources of Central Asia probability forecasting

The Goal

Data:Long-term surface observational data (air temperature, precipitation, annual datesof snow appearance and disappearance), large scale topographic maps, aerialphotographs, and assimilated remote sensing information. (Corona, Hexagon KH-9,Landsat, Aster, SRTM and MODIS)

Methods: - Differences in averages (d= AVE1973-03 - AVE1942-72) for two thirty-year periods 1973-2003 (AVE1973-03) and 1942-1972 (AVE1942-72) and T-test at 20% for precipitation and 10% for air temperature level- Linear trends (α) for two periods (α1942-72 and α1973-03); coefficients of determination, F tests, at 80% for precipitation and 90% for air temperature level of significance- Acceleration in changes for the last thirty years: a = α1973-03 - α1942-72; same significance as for the linear trends- Differences in standard deviations for two periods (dstd = std1973-03- std1942-72) and T-test at 20% for precipitation and 10% for air temperature level. - Geographically Weighted Regression (GWR) spatial interpolation method to interpolate spatial gaps in the meteorological data - Georeferenced and orthorectified image processing and spectral analysis

Some latest publications on climate changes in Central Asian

RegionNumber stations

PeriodResoluti

onResults

Authors

Tien Shan200 > 4000 m

110 1940-1991

MonthlyAir temperature +0.01C/yrPrecip.+1.2 mm /yr<2000m

Aizen, et al., 1997

Central Asia35-50N 75-120E

321951-1990

SummerMongolia and northern China

negative trendYatagai &

Yasunari, 1995

Tajikistan800-4000 m

41930-1991

AnnualAir temperature +2.2C and +0.4C/yr

Осадки+0.05 - 0.25 mm/yr<1000 m+1.82 - +5/37 >2000 m

Finaev, 1995

Central Asiaplains and foothills

26 +501891-1991

Annual and

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 Asia68 - 3614 m

39- 45N 62-78E21

1879-2001

AnnualGrowth of air temperature+ 0.027 C /yr

Giese et al., 2007

Xinjiang 91979–1999

SummerSuccessive droughts for 3 summers(1997-99) at northern China

Xu, 2001

CLIMATE

8450

3828

1812117

0 100

<500500-1000

1000-15001500-20002000-25002500-30003000-3500

>3500m

Number of stations

23

111

117

Beginning of observations 1855-1900

1901-1941

1942-1952

Major period of observations: 1942-1972 and1973-2003

251 meteor-stations used in our analysis Differentiation by climatic regions

Number of stations by elevations

Difference in 30-year averages of annual (A) and summer (B) air temperature(ΔT = AVE1973-2003 – AVE1942-1972)

0.00.10.20.30.40.50.60.70.8

Ara

l-Cas

pean

des

erts

Wes

tern

Pam

irE

aste

rn P

amir

Alta

i-Say

anN

orth

ern

Tien

Sha

nW

este

rn T

ien

Sha

nIs

sik

Kul

Cen

tral T

ien

Sha

nIn

ner T

ien

Sha

nE

aste

rn T

ien

Sha

nK

azak

hsta

n st

eppe

Mon

golia

Tarim

dTan , C

0.00 0.50 1.00

-135 -1000

1000 -2000

2000 -3000

> 3000

dTan , C

H, m

Difference by altitudinal zones, оС

Difference by regions, оС

A

B

,oC

,oC

0.65oC thirty year difference

0.64oC thirty year difference

-0.03

-0.02

-0.01

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

Ara

l-Cas

pean

des

erts

Wes

tern

Pam

ir

East

ern

Pam

ir

Alta

i-Say

an

Nor

ther

n Ti

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han

Wes

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Tie

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an

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l

Cent

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Shan

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r Tie

n Sh

an

Kaza

khst

an s

tepp

e

East

ern

Tien

Sha

n

Mon

golia

Tari

m

aTan

aTs

°C

0.00 0.01 0.02 0.03 0.04

-135 - 1000

1000 - 2000

2000 - 3000

> 3000

aTs

aTan

aT°C

Acceleration of changing annual (aTan) and summer (aTs) air temperatures in Central Asia by regions and altitudes for the last 30 years

Acceleration by regions, оС Acceleration by altitudinal zones, оС

-4-202468

10121416

Ara

l-Cas

pean

des

erts

Wes

tern

Pam

irEa

ster

n Pa

mir

Alta

i-Say

anN

orth

ern

Tien

Sha

nW

este

rn T

ien

Shan

Issi

k Ku

lCe

ntra

l Tie

n Sh

anIn

ner T

ien

Shan

Kaza

khst

an s

tepp

eEa

ster

n Ti

en S

han

Mon

golia

Tari

m

dPan,km3

-30.0

-25.0

-20.0

-15.0

-10.0

-5.0

0.0

5.0

10.0

15.0

Ara

l-Cas

pean

des

erts

Wes

tern

Pam

irEa

ster

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mir

Alta

i-Say

anN

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Tien

Sha

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Shan

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k Ku

lCe

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l Tie

n Sh

anIn

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ien

Shan

Kaza

khst

an s

tepp

eEa

ster

n Ti

en S

han

Mon

golia

Tari

m

dPan,mm

-20 0 20

-135 - 1000

1000 - 2000

2000 - 3000

> 3000

dPan, km3

-20 -10 0 10

-135 - 1000

1000 - 2000

2000 - 3000

> 3000

dPan, mm

Differences in 30-year averages of annual precipitation (ΔPan= avePan1973-2003 – avePan1942-1972)over Central Asia

Difference in annual precipitation by regions, mm

Difference in annual precipitationby area of regions, km3Average weighted altitudinal

difference in annual precipitation by area, km3

Average weighted altitudinal difference in annual precipitation, mm

, mm

Surplus in annual precipitation 355 km3

0

10

20

30

40

50

60

70

80

90

1930194019501960197019801990

Annual and decadal total particle concentration

0.0E+00

1.0E+05

2.0E+05

3.0E+05

4.0E+05

1910192019301940195019601970198019902000Year

Conc

(num

/mL)

Overall decadal trends show the high dust loading for the 1960’s and 70’s, with maximum dust loadingapparent for the 30’s and that is in accordance with results from 154 Chinese stations on maximumfrequency of dust weather for the mid-1960’s (Qian et al; Sun et al., 2002) and the lowest in the 90’s to beone-fifth that of the 60’s.

-25

-20

-15

-10

-5

0

5

Ara

l-Cas

pean

des

erts

Wes

tern

Pam

ir

East

ern

Pam

ir

Alta

i-Say

an

Nor

ther

n Ti

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han

Wes

tern

Tie

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an

Issi

k Ku

l

Cent

ral T

ien

Shan

Inne

r Tie

n Sh

an

Kaza

khst

an s

tepp

e

East

ern

Tien

Sha

n

Mon

golia

Tari

m

dPs, mm

-12

-10

-8

-6

-4

-2

0

2

Ara

l-Cas

pean

des

erts

Wes

tern

Pam

ir

East

ern

Pam

ir

Alta

i-Say

an

Nor

ther

n Ti

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han

Wes

tern

Tie

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an

Issi

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l

Cent

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r Tie

n Sh

an

Kaza

khst

an s

tepp

e

East

ern

Tien

Sha

n

Mon

golia

Tari

m

dPs, km3

-15 -10 -5 0

-135 - 1000

1000 - 2000

2000 - 3000

> 3000

dPs,mm

H, m

-15 -10 -5 0

-135 - 1000

1000 - 2000

2000 - 3000

> 3000

dPs,km3

H, m

Differences in 30-year averages of summer precipitation (ΔPs= avePs1973-2003 – avePs1942-1972) over Central Asia

Difference in average weighted summer precipitation by regions, mm

Difference in average weighted summerprecipitation by area of regions, km3

Altitudinal differences in average weighted summer precipitation, mm

Altitudinal differences in summer

precipitation by area, km3

, mm

Difference in 30 -year averages of winter precipitation(ΔPw = AVE1973-2003 – AVE1942-1972)

-10

-5

0

5

10

15

Ara

l-Cas

pean

des

erts

Wes

tern

Pam

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ster

n Pa

mir

Alta

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orth

ern

Tien

Sha

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ien

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anIn

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ien

Shan

Kaza

khst

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tepp

eEa

ster

n Ti

en S

han

Mon

golia

Tari

m

dPw, mm

-202468

1012

Ara

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pean

…W

este

rn P

amir

East

ern

Pam

irA

ltai-S

ayan

Nor

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Inne

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n Sh

anKa

zakh

stan

ste

ppe

East

ern

Tien

Sha

nM

ongo

liaTa

rim

dPw, km3

-5 0 5 10 15 20

-135 - 1000

1000 - 2000

2000 - 3000

> 3000

dPw, km3

-5 0 5 10

-135 - 1000

1000 - 2000

2000 - 3000

> 3000

dPw, mm

Difference in average weighted winter precipitation by regions, mm

Difference in winterprecipitation by area of regions , км3

Difference in average weightedwinter precipitation by elevation, mm

Difference in winter precipitation by elevations, km3

, mm

-3

-2

-1

0

1

2

3

4

Ara

l-Cas

pean

des

erts

Wes

tern

Pam

ir

East

ern

Pam

ir

Alta

i-Say

an

Nor

ther

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han

Wes

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Tie

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an

Issi

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Cent

ral T

ien

Shan

Inne

r Tie

n Sh

an

East

ern

Tien

Sha

n

Kaza

khst

an s

tepp

e

Mon

golia

Tari

ma, mm yr-1

-2 0 2 4 6

-135 - 1000

1000 - 2000

2000 - 3000

> 3000

a, mm yr-1

H, m

Acceleration of changing annual precipitation for the last 60 years (Δ = SLOPE1973-2003 – SLOPE1942-1972)

Annual acceleration by regions

Annual acceleration by altitudes

, mm

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.

SEASONAL SNOW COVER

Tien Shan, number of days with snow 2000-2001

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

Tien Shan, number of days with snow 2006-2007

GLACIERSSome recent publication on Central Asia glacier changes

Authors Regions Period Data and methods Area of glacier recession, km2

Khromova , etal., 2003

Akshiirak, Inner Tien Shan

1977-2001 Map 1977, ASTER image 406.8-93.6 (-23%)

Vilesov and Uvarov, 2001

Zailiiskiy Alatau’N. Tien Shan

1955-1990 Aerial photography 287.3-81.8 (-29%)

Bolch, 2006 Zailiiskiy AlatauN. Tien Shan

1979-1999 1:100000 maps, Landsat ETM 198.37-34.2 (-17.3%)

Niederer et al.2008

Sokuluk River basin, N. TienShan

1963-1986 1:25,000 maps, KFA1000 satellite photo 31.7-4.2 (-13.3%)

1986-2000 Landsat ETM+ 27.5-4.7 (-17.1%)

Ye et al. 2005 Glacier № 1Urumqi R. basinE. Tien Shan

1962-2003 Maps 1962, 1964, 1986, 1992, 1994, 2000 and 2001

1.94-0.24 (-12.4%)

Narama et al.,2006

Terskei AlatooN. Tien Shan

1971-2002 Corona , Landsat ETM+ 245-18 (-8%)

Liu et al., 2006 Aksu R. basinC. Tien Shan

1963-1999 Maps 1:100000, Landsat TM и ETM 176-58.6 (-3.3%)

Kaidu R. basin,C. Tien Shan

1963-2000 33-38.5 (-11.6%)

Aizen, et al. 2007 Akshiirak,Inner Tien Shan

1977-2003 Aerial photography, ASTER 406.835.15 (-8.6%)

Glacier covered area recession during the last 30 years:

• Тянь-Шань -709 км2 (-7.1%)• Алтай -86 км2 (-6.2%)

1973

2003

8.3% 12%4,6% 6.5%3%

Atbashi glacierized area, Inner Tien Shan, -5.6% area reduction for the last 30 yearsSeptember 2003 September 1973

Borohoro glacierized area, Eastern Tien Shan, -5.7% area reduction for the last 30 yearsSeptember 2003 September 1973

Djungarskiy Alatau glacierized area, Northern Tien Shan -8.0% area reduction for the last 30 years

September 2003 September 1973

Aksiirak glacierized massif

182 glaciers

427 km2 glacierized area

(aerial photogrammetry 1943)

19431977182 glaciers

406.8 km2 glacierized area

4.2% area reduction

(aerial photogrammetry 1943/1977)

2003178 glaciers

371.6 km2 glacierized area

8.7% area reduction

(aerial photogrammetry 1977/ASTER2003)

Inner Tien Shan

2003 2002199519771956194318691800

Petrov Glacier

To maintain Central Asian glaciers at the current state, the increasing summer airtemperature at the ELA (TsELA) (equilibrium line altitude) must be offset by acorresponding increase in annual precipitation. For example, the glaciers of Tien Shanwill not retreat if an increase in mean summer air temperature on 1.0 ºC atELAcoincides with an increase of annual precipitation of 100 mm atELA.

PELA = 0.0995TsELA + 0.7441

R2 = 0.980.6

0.7

0.8

0.9

1.0

1.1

-1 0 1 2 3 4 TsELA

PELA, m

Glaciers exist while ELA is below the upper boundary of GCA (glacier covered area) inthe basin. This chain can be diagrammed as follows: climate → ELA → Glacierdimensions/configuration, and, ultimately, glacier ice volume.

Forecasted decrease in number of glaciers (K), glacier covered areas (S) andvolume (V) relatively to current glacier covered area under theELA moving up

Both models forecast that significant glacier degradation begins when ELA is increased by 600 m . The Central Asia GCA may shrink to about half of the current state if ELA increases another 1000 m. The number of glaciers could decrease by 40% and glacier volume by 60%.

The annual runoff of the major Tien Shan rivers is on average 67 km3 yr-1, which includes glacial melt of about 14 km3 yr-1 (20%)

For the last thirty years (1973-2003), the long-term mean runoff on average increased by 2% compared with previous thirty years, while thirty year mean in annual maximum runoff decreased by 5% of average

RIVER RUNOFF

Relative changes of the last thirty year annual mean (dQan/Qan) and maximum (dQmax/Qmax) river runoff in comparison to sixty year averages, % , and changes in dates of maximum river runoff (ddQmax).

%

Differences in 30-year averages of annual (dQan) and glacier (Qgl) river runoff (a) and their relation (b).

a b

Significant temporal and spatial changes have occurred in Central Asia in the inter-annualsurface water distribution between upper, middle, and lower river reaches, while annualrunoff did not changed significantly.

Precipitation and potential evaporation have similar ranges.

1957 1961 1965 1969 1973 1977 1981 1985 1989 1993

Years

Laye

r w.e

., m

m

Precipitation Runoff

-1000

100

300

500

700

900

1100

1997 2001 2005

Potential Evaporation

Average computational river runoff , precipitation and potential evaporation for the Tien Shan region during last 50 years

0.3

0.8

1.3

1.8

2.3

T T+1 T+2 T+3 T+4 T+5

E/Ec,P/PcR/Rc, E*/E*c

Sir Dar'ya P/PcE/EcR/RcE'/Ec'

Ratios between predicted by 2100 and current river runoff (R/Rc), evapotranspiration(E/Ec), potential evaporation (E*/E*c) under predicted changes of air temperature (Tc+d;d=1,2,…5°C) and precipitation (mPc, m=0.9; 1, 1.1, …1.5) for the Sir Dar’ya R. basin.

The Magicc&ScenGen Global Climatic Model (IPCC, 2001) scenarios considered that annual average air temperature in Central Asia by 2100 increases between 1.8 and 4.4°С and precipitation by 6% of current rate.

Rapid current decline of water resources in central Asia related to factors such as :

- (i) the rise of global and regional air temperatures

- (ii) shrinkage of seasonal snow cover and degradation of glaciers

- (iii) decrease of precipitation in the Alpine areas

- (iv) partitioning among snow and rain, evaporation fluxes

- (v) poor management of regional water resources.

The diminishing natural water storages significantly affect river runoff, lake levels, andgroundwater in aquifers, and contribute to progressive droughts that causesalinization and desertification in central Asia.

Conclusion