Contemporary and prognoses changes of snowiness and glaciation

Contemporary and prognoses
changes of snowiness and
glaciation in zone of runoff
formation and their probable
impact on water resources of
Central Asia
by
Igor Severskiy
Institute of Geography, Kazakhstan
Tien Shan, Dzhunghar Alatau, Pamirs
Dzhunghar
Alatau
Tien Shan
Hissar-Alay
Pamirs
Tien Shan
Hissar-Alay
Pamirs
The main aspects of the project in close
connection with problem of climate
change. Taking into account the results of
our research I have to say that spread
opinion about significant impact of human
activity on climate does not reflect the real
changes in climate. The main basis for this
mistake is two reasons as minimum.
The city landscape considerably
distorts the natural climate. This
is well seen on satellite images
made during the night in a warm
range. Towns can be sharply
distinguished on such images
using the temperature field.
Each small or large populated
center is seen on the general
temperature background of a
satellite image as a high
temperature spot with clearly
outlined boundaries. The
difference in the temperatures
of a town and its surroundings
for large towns may reach 5-6°C.
Astana
23.01.0
3
21.02.03
20.03.03
02.04.0
3
13.05.03
23.06.03
12.07.0
3
24.08.03
08.09.03
11.10.0
3
21.11.03
Sizes, configuration and
position of a thermal spot in
relative to meteorological
station can considerably
change not only from month to
month, but also within a week.
The degree of distortions of
natural fields of climatic
characteristics is determined
by the position of a
meteorological station in
relation to the borders of a
thermal spot, sources of
thermal pollution etc. Probably
it is the main reason of the big
difference in rates of warming,
even within small areas.
Greatest difference between temperature inside and
outside the thermal spot versus the area of the
thermal spot
F,km2
700,0
600,0
500,0
400,0
300,0
200,0
100,0
0,0
0,0
2,0
4,0
6,0
8,0
10,0
Δt°C
Change of mid-annual temperature
averaged on the territory of Kazakhstan
(1936 – 1996).
t,C
12
y = 0,0086x - 8,9255
10
8
6
4
2
0
1930
1940
1950
1960
1970
1980
1990
2000 year
Change of glaciation area on the northern
slope of Zailiiskiy Alatau ( 1955 - 1990)
Authors
Area of glaciation
km2
Mean annual rate of reduction of
glaciation area
km2
Yrs
1955
Cherkasov 271,2
Vilesov,
Uvarov
272,8
1979
%
1990
1951979
1979- 1955 1955- 1979 19551990
- 1979
- 1990
1990
1990
228,2 204.7
1.80
2,14
1.90
0,66
0.94
0.70
229,0 203,5
1,82
2,32
1.98
0,67
1,01
0,72
Change of glaciation area on the northern
slope of Zailiiskiy Alatau (1955 – 1990)
Authors
Area of glaciation, km2
1955
1975
1979
1990
Mean annual rate of reduction of
glaciation, %
1955 1955 1975 1975 1979 19561975 1979 1979 1990 1990 1990
-
1
271,2 240,4 228,2 204,7 0,57
0,66
1,27
0,99
0,94
0.70
2
287,3 -
0,85
-
-
1,01
0,83
3
287,3 240,4 228,2 204,7 0,83
0,86
1,27
0,99
0,94
0,82
229,0 203,5 -
Note: 1-Cherkasov 2- Vilesov, Uvarov ;
3- obtained for study
Изменение темпов сокращения площади
оледенения Заилийско--Кунгейской ледниковой
системы.
Сокращение площади
Период
Средний
год
периода
км2
%
% в год
1955-1975
1965
46,9
16,32
0,82
1955-1979
1967
59,1
20,57
0,86
1975-1979
1977
12,2
5,07
1,27
1975-1990
1983
35,7
14,85
0,99
1979-1990
1985
23,5
10,30
0,94
1990-1999
1995
16,48
8,05
0,89
Изменение суммарной площади ледников
Джунгарской ледниковой системы за период с 1956 по
1990 гг.
Темп сокращения, площади ,%/год
Район, бассейн реки
1956-1972
1972-1990
1956-1990
Южный склон Джунгарского
Алатау
1,239
1,175
1,082
Бассейн реки Каратал
1,123
0,846
0,895
1,342
0,603
0,884
0,662
0,859
0,715
1,185
0,854
0,924
Бассейны рек Биен, Аксу, Лепса
Бассейны рек Тентек, Ыргайты
Джунгарская ледниковая система
в целом
Change of ice volume of glaciers of ZailiiskiyKungei glacial system (1956 -1990).
Region,
river
basin
Ice volume ,km3
Mean annual rate of
reduction of glaciation ,
%
Yrs
1956
1975
1
(6.6)
4.34
1.8
2
(6.7)
6.22
0.38
3
(13.2)
11.34
8.83
8.43
4
16,04
16.96
13.73
12.76
(42.5)
38.86
Total
1979
1990
19551975
0.70
19751979
19791990
19551990
5.53
0.41
1.03
4.76
0.64
0,58
0.45
1- Southern slope of the Kungei Ala-Too range; 2- Chon-Kemin river
basin; 3- Northern slope of the Zailiiskiy Alatau range; 4- Chilik river basin
Change of ice volume of glaciers of Dzhunghar glacial system
(1956-1990)
Region, river
basin
Ice volume , km3
Mean annual rate of
reduction of glaciation, %
Years
1956
1972
1990
19561972
19721990
1956
1990
Southern slope
11,1
8.12
6.14
1.68
1.36
1.32
Karatal river
basin
9,8
8.05
6.83
1.12
0.84
0.89
Biyon, Aksu,
Lepsy river
basins
14,3
12.1
10.03
0.96
0.95
0.88
Tentek,
Yrgaity river
basins
Total
4,3
3.94
3.25
0.52
0.97
0.72
39.5
32.2
26.25
1.16
1.03
0.99
Change of rate of glaciation area reduction on the northern slope
of Zailiiskiy Alatau (1955-1990)
Deviation of annual sum of precipitation from the mean (19601990) in Zailiiskiy (1) and eastern part Terskey Alatоо (2)
Х,mm
300
,
200
100
0
-100
-200
-300
-400
1960
1
2
1970
1980
1990
Years
2000
h, sm.
80
а
60
row 1
row 2
row 3
40
20
0
years
1960 1965 1970 1975 1980 1985 1990 1995 2000
50
h, sm.
б
40
row 1
row 2
row 3
30
20
10
0
years
1960 1965 1970 1975 1980 1985 1990 1995 2000 2005
h, sm.
50
40
в
row 1
row 2
row 3
30
20
10
0
years
1960 1965 1970 1975 1980 1985 1990 1995 2000 2005
Changes of mean
decadal height of
snow cover in
February and
corresponding
liner trends
Tuyuksu glacier
Cumulative specific net mass
balance of Tuyuksu glacier
Cumulative
net
balanse
[mm]
CUMMULATIVE SPECIFFIC NET BALANSES
2000
0
-2000
-4000
-6000
-8000
-10000
-12000
-14000
-16000
-18000
-20000
1957
1962
1967
1972
1977
1982
Time [Years]
1987
1992
1997
2002
Surface height changes of the open part of the
Tuyuksu glaciers (1958-1998)
•During the 40
years Tuyuksu
glacier has
receded 1 km and
had lost 41
million m3 of ice.
Total reduction of
thickness of ice at
the end of the
tongue of the
glacier has
exceeded 45 m
(marked in red).
On the most part
of the glacier the
loss of thickness
of ice was from 5
up to 15 m
(orange, yellow).
•F
o
r
4
0
y
e
a
r
s
T
u
y
u
k
s
u
g
l
a
Surface height changes of the open part
of the Tuyuksu glaciers (1958-1998)
•At the same time,
in a considerable
part of the
accumulation zone
the mass balance
was positive. The
thickness of new
accumulation layer
was from 5 to 25 m.
Changes in the glacial runoff in basins of Southern
.
slope of Dzhungarskiy Alatau in 1956-90
River
Chorgos
Area of
a basin,
km2
Total
runoff,
Q, 106
m3
Glacial runoff, Qл
1956
1990
106 м3
Qл/Q,
%
106 м3
Qл/Q,
%
1310
508
97
19,1
71
14
96
39
16
41
15
38,5
144
80
31
38,8
23
28,8
92
21
2
9,5
1
4,8
Usek
1130
562
136
24,2
100
17,8
T o t a l ,
average
2772
1210
282
23,3
210
17,4
Chizhin
Tyshkan
Burchan
Change of glacial runoff of the Usek river
180
160
150
140
y = -1.0129x + 2114.6
130
120
110
100
90
80
70
60
50
__________ __________ _______
___.1. __________ ____ _. ____
_____ ______
1996
1994
____
__________ ____ __ ______ ___
1995
1993
1992
1991
1990
1989
1988
1987
1986
1985
1984
1982
1983
1981
1980
1979
1978
1977
1976
1975
1974
1973
1972
1971
1970
1969
1968
1967
1966
1965
1964
1963
1962
1961
1960
1959
1958
1957
1956
40
1955
__________ ____, 1000000 ___._
170
In spite of the considerable degradation
of glaciation the annual runoff did not
change during the last decades,
therefore we suppose an existence a
certain compensating mechanism. If the
temperature rises such a mechanism can
be more and more effective in runoff
formation due to the thawing of
underground ices, including those
accumulated in perennial permafrost.
Surface height changes of the buried
part of Tuyuksu glaciers (1958-1998)
• Total loss of ice
volume of the
buried part of
the glaciers is
equivalent to 20
% of the total
loss of ice of the
open part of the
Tuyuksu
glaciers.
•In other words, the volume of
water formed out of thawing of
the buried part of glaciers was 20
% of the total runoff formed at
the expenses of thawing of the
open part of these glaciers. This
is very considerable value which
were not taken in consideration
yet in water balance calculation.
This volume is enough for
compensation of runoff losses
due reduction of glaciation area
Volume of water formed out of thawing of perennially
frozen ground at the Small Almatinka river basin (1973
– 1996)
Interval Belt area, Volume of
of
thousan
thawing
height,
ds of m2
ice,
m a.s.l.
thousan
ds of m3
3200-3500
2027,0
395,3
Volume of
water
(under icy
ability of
30%),
thousands of
m3.
316,2
>3500
3240,7
1069,4
855,5
Total
5267,7
1464,7
1171,8
The volume of water originated from
thawing perennial permafrost is only
about 6 % of annual runoff of Tuyuksu
glaciers during 40 years. Thus, the
major compensation of runoff is
produced not by the of thawing
perennial permafrost but by the
thawing of buried glaciers and rockglaciers.
Thus, the water provided by the buried
glaciers and rock glaciers compensate the
greatest part of the runoff loss due to the
decrease of the ablation area and stabilizing
the runoff. Because the resources of
underground ice are comparable with ice
resources of the modern terrestrial
glaciation it is possible to assume that even
in case of continuation of the intensive
degradation of glaciation the runoff during
nearest decades will not be considerably
changed.
Conclusion
1.Significant warming shown by
meteorological records does not
reflect the real climatic changes,
but is rather the result of
anomalies accumulated through
time in the natural temperature
field recorded under the warming
influence of urban territories.
2. Present-day warming reflects the
trend in natural cyclic climate
variations and the role of the
anthropogenic component in this
process is not as large as it is usually
supposed. So, there is not enough
evidence to expect the predicted
warming of 2-4 degrees C for the near
future.
3. At the same time, it is evident
that the air temperature in
Central
Asia
is
slowly
increasing. The indirect proof of
this process is the considerable
reduction of glacier resources
of the mountains of Central
Asia (more than 35% during the
last 40 years).
4. Glacier resources in the Tien Shan
are decreasing at the rate of 0.82 (area
of glaciers),1.0% ( volume) per year
during the last 50 years .
The common opinion about the
inevitability of glacier disappearance in
Central Asia mountains cannot be
accepted as an axiom. Taking into
account stability in precipitation and
especially in snow resources, one can
suppose that glaciers in this region will
not disappear during this century.
5. In spite of considerable reduction
in glacier resources, the runoff of
the main rivers has not changed
during the last decades which is
evidence of a certain compensating
mechanism. Such a mechanism
could be related to the water inflow
from underground melted ice.
6. The forecast for the near future
of significant decrease of water
resources
connected
to
the
anthropogenic warming is hardly
possible. Therefore there are not
sufficient reasons to fear the
significant climate warming, the
corresponding diminution of the
water resources, and connected
economic losses.
In view of cyclic character of natural changes
of a climate, reduction of the rates of glaciation
degradation in the Tien Shan and Gissaro-Alai
in the 1980s- 1990s and considerable mass
increase in the feeding zone of Tuyuksu
glaciers group in the period from 1958 to
1998, it is possible to assume, that in the
foreseeable future the modern stage of
degradation of glaciation may replaced on
opposite sign.
Moreover, 14 large glaciers, which in
the last decade of the XX century
started to move down, were
discovered in Central Karakorum.
During the period from 1990 to 2001
tongues of some glaciers moved
forward at a distance from 150 m to
2.5 km, with 5-50m thickening in the
lower and middle parts of ablation
zone [Hewitt K., 2005].