9.3
SIMULATION AND STOCHASTIC FORECASTING OF WATER CYCLE COMPONENTS IN CENTRAL ASIAN ALPINE BASINS Vladimir B. Aizen*, Elena M. Aizen (University of Idaho, U.S.A.) Valeriy A. Kuzmichenok Water Resources and Hydropower Research Institute, Kyrgyzstan)
ABSTRACT: To estimate modern condition of river runoff
Hypothetical climate-change scenarios in Tien
in Tien Shan alpine basins and to forecast its variability in
Shan modeled as a stepwise progression predict an
relation with global and regional climate changes, the
increase in air temperature of 1.8ºC - 4.4ºC (i.e., on
mean of the major water cycle characteristics (air
о average 3 С) and precipitation at 0.94 to 1.54 times (1.2
temperature, precipitation, evapotranspiration and river
times) during the XXI Century, which will lead to a
runoff) have been simulated using data from 212 hydro-
increase of river runoff by 1.047 times. If we assume
meteorological stations and 304 precipitation gauges.
that precipitation remains constant and air temperature
The mean evapotranspiration was calculated using data
о increases by 5 С, river runoff in central Asia can
on air temperature, precipitation, and the topography
decrease 0.66 due to increased evapotranspiration by
aspects (including type of vegetation). The findings were
1.24 times.
simulated over Tien Shan relief using rectangular coordinates of the equivalent cone projection with
1. INTRODUCTION
standard parallels using 1:500 000 scale 100 m grid
The water-issue problems that occur during times of
resolution Digital Elevation Modal that covers 800 000
persistent drought [Agrawala et al., 200] are extremely
knotted points. Applicable GIS-based distributed River
important for central Asia. With the total population
Runoff Models were implemented in regional conditions
reaching 100,000,000 at the end of the 1990s, water
and tested in two Tien Shan basins, taking into account
demand is increasing while the supply is potentially
glacial
decreasing. central Asia is the world’s largest closed
melt,
forest
and
irrigated
areas.
The
2
parameterization between measured and simulated
drainage basin, with area of more than 5,000,000 km
runoff occurred by least square method with discrepancy
receive and retain at least 10% of the western external
approximation
multiple
atmospheric moisture [Kuznezova, 1984; Aizen and
parameters: annual precipitation, snow and glacial runoff
Aizen, 1997]. Despite the presence of large deserts and
and first-derivative of previous year river runoff. The
prairies with very low precipitation and extremely dry
mean square discrepancy between measured and
climates, central Asian mountains hold one of the
simulated runoff was in accordance with root-mean-
greatest concentrations of perennial snow and ice in the
square error of measured runoff ranging from 8% to 12%.
mid-latitudes and constitute a vital source of water for
The level of calculated evapotranspiration revealed the
more then seven thousand lakes with a total area of
same order as the river runoff.
2 445,400 km including the Caspian, Aral, Balkhash, Issik
_____________________________________________
Kul and Lobmor lakes [Aizen, 2003]. However, in last
1
Corresponding author address: Vladimir B. Aizen,
few decades, the gradual desertification of central Asia
Department of Geography, College of Science, P.O. Box
has observed [Vaganov, 1998; Voropayev, 1997,
443025,
Glantz, 1999]. There are approximately 30,000 glaciers
using
Moscow,
ID
linear
functions
83844-3025,
with
U.S.A.;
e-mail:
2 with a total area of 25,000 km in central Asia [Haeberli,
[email protected]
1995] that have been receding since the middle of the
1
19th century, with 12% that have already disappeared
where H is elevation of a grid point; X and Y are
[Aizen and Aizen, 1997; Aizen et al., 2004a].
orthogonal coordinates relative the central grid point.
Moreover, during the last 50 years, most the
There were 9 knotted points at each grid including one
measured increases in precipitation and glacier melt
central point with the weight of ‘10’, four site points with
were not associated with a synchronous rise river
the weight of ‘1’ and four diagonal points with weight of
runoff in low reaches while the central Asian lake
‘0.707’. Index of orientation (P0) and angle of orientation
levels have dropped, which suggests an increase of
(O) were computed by equation 4:
water loss to evapotranspiration and possibly as percolation to the ground aquifers that result in
2 2 1/2 cosU = 1/(1 + a2 + a3 )
(2)
progressive droughts and aridization. More than one-
tg(E + dE) = a2/a3
(3)
third of the lakes with surface areas between 1 and 5
Po = cosO = cosUcos(F-δ0) + sinU {cosα
2 km have disappeared [Aizen et al., 1997a; Aizen et
[tgFcos (F-δ0) - sinδ0secF]},
(4)
al., 2003]. Currently, available general circulation models suggest that the summertime increase in
where dE is approach of meridians in the equivalent
diurnal temperatures in central Asia is likely to be
conical projection, which is the function of latitude; F is
significantly greater than that in other regions [IPCC,
latitude of knocked point; δ0 – declination of sun in local
II, 2001]. Therefore, a further decline in central Asian
noon of summer solstice (23,°5); α is astronomical
water resources is expected. It is likely that increased
azimuth of projection on horizontal surface orthogonal to
temperatures will cause further deglaciation and loss
vector surface.
of snow-covered areas, which could increased
evaporation
and
aridization
result in of
sub-
2.2. Simulation of the long-term mean water cycle
mountain and plain areas. In several regions of
characteristics (i.e., air temperature, precipitation,
central Asia, threshold conditions exist for irreversible
evapotranspiration and river runoff) were based on
desertification. However, there had not been any
meteorological,
precise estimation on the modern state of water cycle
glaciological information [Glazirin et al., 1993; Applied
components and consequent changes in river runoff.
Reference Book on Climate, 1989; Reference Book on
The main objective of the presented research is
Climate 1966-1969]. The data are a part of the Central
simulating, estimating, and predicting the water cycle
Asian Database (CADB), which is being developed at
components in central Asian basins.
the University of California Santa Barbara and the
topographic,
hydrological
and
University of Idaho, Moscow. The findings were 2. DATA and METHODS
simulated over the Tien Shan relief using orthogonal
2.1. Topography: The basis of the Tien Shan
coordinates of the equivalent cone projection with
topography was Digital Elevation Model (DEM)
standard parallels using a 1:500,000 scale with 100-m
developed with resolution of 741 m (24”) along
grid resolution of the Digital Elevation Model that covers
meridians, 721 m (31”) along parallels and 1m along
800,000 knotted points. The accuracy in determining the
elevation. The piecewise-smooth patch of the surface
station coordinates was less 0.1-0.5 km.
was
used
to
determine
the
coefficients
of
approximation (ai) (eq.1), angle of slope (U) (eq.2)
2.2.1. Digital Model of Mean Air Temperatures (DMMAT)
and exposition (E) (eq.3) of macro-slope for each
(monthly and annual): Triangulation Irregular Network
grid-point:
(TIN) with 176 triangles was developed based on data from 108 meteorological stations. The optimization 2
2
H = a1 + a2X + a3Y + a4 XY + a5 X + a6Y ,
(1)
method of random set triangulation [Kuzmichonok, 1990]
2
was implemented using the criteria of minimum angles
in pare of contiguous triangles taking into account the
Figure 1. Triangulation Irregular Network and meteorological stations used in simulation of air temperature over the central and western Tien Shan.
topography (Fig. 1). The distribution of stations via
are located below 2500 m (Fig. 3). Hence, all
latitude, longitude, elevation and periods of air temperature observations is shown at the Fig. 2.
Table 1. Parameters of determining the monthly,
Monthly and annual air temperature changes via
seasonal and annual mean air temperatures. r is
elevation were computed based on data from 212
correlation coefficient; m is mean square error of
stations using the least square method (eq. 5, Fig.3).
approximation and mb is mean square error in determining the b coefficient (i.e., altitudinal gradient
T = a + bH,
(5)
of air temperature changes).
where T is air temperature at station located at H, km,
Months Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Winter Spring Summer Autumn Year
elevation; a and b are empirical coefficients (Table 1). 2.2.2. Digital Model of Annual Mean Precipitation (DMAMP): Spatial distribution of precipitation in the Tien
Shan
basins
were
studied
in
numerous
investigations [Getker, 1985; Bakirov 1988; Aizen et al., 1995a,b; 1997b]. However, significant regional spatial and altitudinal variability of precipitation complicate mathematical simulation of precipitation distribution
with
high
resolution
(micro-scale).
Furthermore, the main existing meteorological stations
3
r -.71 -.77 -.89 -.94 -.95 -.96 -.94 -.92 -.90 -.89 -.82 -.75 -.74 -.94 -.94 -.88 -.90
A -1.07 1.98 9.11 16.98 22.74 27.50 29.89 28.07 22.20 14.86 7.51 2.25 1.02 16.27 28.49 14.86 15.17
b -4.18 -4.59 -5.21 -5.68 -6.03 -6.53 -6.30 -5.75 -5.12 -4.70 -4.57 -4.44 -4.40 -5.64 -6.19 -4.79 -5.26
m 4.0 3.7 2.5 1.9 1.8 1.9 2.2 2.3 2.4 2.3 3.1 3.7 3.8 2.0 2.1 2.5 2.4
mb .29 .26 .18 .14 .13 .14 .16 .16 .17 .17 .22 .27 .27 .14 .15 .18 .17
available data related to estimations of precipitation
and
were applied including 304 meteorological stations
precipitation were estimated using in-situ glaciological
[Applied
measurements [Dikikh and Mikhailova,1976; Aizen
Reference
Reference
Book
Book
on
on
Climate
Climate,
1989;
1966-1969];
23
328
high
altitudinal
points
where
annual
1985; Kotlyakov, 1988; Makarevich, 1985 Glazirin et al.,
precipitation gauges (CADB), 103 interpolation points
1993].
Figure 2. Distribution of meteorological stations in Tien Shan (ms) with air temperature observations.
60
20 10 0
40 20
40 20 0 0
68 70 72 74 76 78 80 82 Longitude (E)
42
38
40
0 Latitude (N)
80
2000 Altitude (m)
4000
160
60
Number ms
120
40 20 0
40 1981
1971
Year of observations
1961
1951
1941
1931
1921
1911
1901
0
90
1891
10 30 50 70 Number years of observations
80
1881
N umber m s
60 Number ms
Number ms
30
36
Number мs
40
Table 2. An example of long-term mean of summer air temperature (Tse.l. ) and annual precipitation (P) at the elevation of glaciers’ equilibrium line (H e.l.). Glacier Tuyksu Golubina Kara-Batkak Sari-Tor Inylchek Abramova
2
S, km 3.8 9.4 4.5 3.3 223.6 22.8
He.l., m 3830 3840 3770 4260 4500 4260
Tsel.°С 2,23 2,29 3,03 -0.,46 -0,72 2,54
P,mm 989 954 1037 728 643 1000
Data from [Kotlyakov, 1988; Makarevich, 1985] [Aizen 1985; Aizen an Aizen, 1997; CADB] [Dikikh and Mikhailova,1976 ] [Duyrgerov et al., 1992] [Dikikh and Dikikh, 1985 ; Aizen et al., 1997c] [Glazirin et al., 1993]
Assuming that annual amount of precipitation (P) is
The annual precipitation has been calculated at the
a function of summer average air temperatures (Tse.l)
height of equilibrium line of each Tien Shan glacier
at the elevation of equilibrium line location. To develop
using data from the USSR and China Glacier
the P/Tse.l relationship (eq.6) data from six Tien Shan
Inventory [Catalogue USSR glaciers, 1970 – 1978;
and Pamiro- Alai glaciers (Table 2) were used. Mean
Glacier Inventory of China, 1986 a;b;c; 1987]. The
square error of approximation was 21 mm.
elevations of equilibrium line for each glacier were further corrected using a method of ‘concentric
P = 99.5 Tse.l + 744.1,
(6)
vicinities’
[Kuzmichonok,
1993].
TIN
with
1454
triangles (Fig. 4) was developed based on data from
4
758 sites where annual mean precipitation data were available.
N um ber m s and ps
100
Number years of observations
1981
1971
0 1961
10 20 30 40 50 60 70 80 90
4000
200
1951
0
2000 Altitude (m)
300
1941
50
0
400
1931
100
100 80 60 40 20 0
Longitude (E)
1921
150
68 70 72 74 76 78 80 82
1911
36 37 38 39 40 41 42 43 Latitude (N)
1901
0
1891
50
100 80 60 40 20 0
1881
100
N umber ms and ps
150
N um ber m s and ps
N um ber m s and ps
N um ber m s and ps
Figure 3. Distribution of meteorological stations (ms) and gauges (ps) measured precipitation over the Tien Shan.
Years
Figure 4. Triangulation Irregular Network and all observational sites used in simulation of annual precipitation over the Tien Shan.
2.2.3. Digital Model of Annual Mean Potential
annual potential evaporation (E*,m) using annual mean
Evaporation (DMAMPE): The amended Ivanov’s
air temperatures (T C) and annual precipitation (P,m)
method [Ryazanceva, 1965] was used to estimate the
data instead of relative humidity, and topography (H, km)
5
instead
of
atmospheric
pressure.
from
[Ryazanceva,
of
(Table 2). The water losses for irrigation were estimated
1965;
as additional evaporation from the irrigated lands under
Sevast’yanov and Smirnova, 1986] were used to get
the long-term annual mean of 300 mm. Simulation of
approximation of potential evaporation (equation 7)
annual river runoff was occurred for the period from
using least square method. Mean square error of
1957 to 1993. Water balance components were
annual approximation was 97 mm.
calculated for each map knocked points related to the
measurements
Data
basins. The mean square residual between simulated ∗
3,0889
E =[0,00005581(27,24 + T)
3 and measured annual runoff was 0.54 km under mean
]⋅[0,7956 +
0,3279⋅H
]⋅[0,3622+0,00483⋅P-0,9043]
0,1155⋅H⋅e
3 square variability of 0.054 km for the first basin and
(7)
3 3 respectively 0.148 km and 0.083 km for the second
2.2.4.
Digital
Model
of
Annual
basin.
Mean
Evapotranspiration was based on DEM (2.1), DMAMP (2.2.2) and DMAMPE (2.2.3) and Digital mapping of
3.2. Optimization of simulation. To optimize simulated
forest and irrigated areas in scale of 1:500 000 with
water
accuracy of 0.25 km [Forest, 1986]. Mean annual
between discrepancy in calculated - measured runoff
evaporation
and different parameters were computed (Table 4). The
(E)
for
each
knocked
point
was
balance
components
correlation
coefficients
most significant correlation is related to precipitation
calculated through equation (8):
amount for the current year, because the simulated E = (P∨E*)[0.625(2.6578-ch
1.0625
model based on limited number of precipitation sites,
U) + 0.2264thC -
which do not present real distribution of precipitation at
(0∨0.7955)]/{1 + 0.9016P0.9409/[E* + 0.0884(P0 0.94)]
0.5561 0.7307
}
,
the basin. Another important parameter that significantly
(8)
correlated with calculate-measured runoff discrepancy is the first derivative from annual river runoff for the
-1 where C is a mean surface flexion, km ; Po index of
pervious year. Obviously, in the years with low water,
orientation; ∨ is logical OR operation; ch is hyperbolic
the river runoff is replenished from the ground aquifers
cosine; th is hyperbolic tangent; P∨E minor; 0∨0.7955
but during the years with abundance of water the river
meaningful coefficient if the knocked point is related
runoff replenishes the ground aquifers. The river runoff
to forested area.
discrepancy
was
approximated
by
different
combinations parameters presented in Table 4. The
3. RESULTS
residual accuracies of approximation are presented in
3. 1. The validation of simulations occurred in two
Table 5. These assessments revealed the most
Chon Kemin River sub-basins (Table 3). The mean
reasonable approximation is linear function with annual
annual runoff was calculated as a difference between
precipitation (Pi), glacier mass balance (Bi), river runoff
annual volume of precipitation and annual volume of
' (R0) and its first derivative (R0 ) for the conducting
evapotranspiration. The hydrological gauges were
previous and current years. The applying corrections
located in the rocky canyons and therefore we may
(∆Ch.
assume that ground and under-channel water flow are
1,2;
eqs. 9 and 10) (Fig. 5) have decreased the
mean square errors of annual river runoff simulation by
minimal. The annual variability in glacier mass
2.5 times (Fig. 6) and, the mean square discrepancy
balance and annual water loss for irrigation were
between measured and simulated runoff was in
taken into account. We also made an assumption that
accordance with root-mean-square error of measured
Chon Kemin Basin glaciers’ mass balance is equal to
runoff ranging from 8% to 12%. Cumulative corrections
mass balance measured on the Tuyksu Glacier
to the values pointed, that at the beginning of 70
6
th
intensive depletion of aquifers has been occurred
(Fig. 5b).
’ ∆ Ch. 1 = 0.21417 + 0.96925⋅P – 0.06544⋅B – 1.31472⋅R0 – 0.68618⋅R0 ’ ∆ Ch. 2 = 0.08261 + 1.20798⋅P – 0.07770⋅B – 0.94741⋅R0 – 0.76925⋅R0
(9) (10)
Table 3. Parameters of Chon Kemin River basins with river runoff measurements at the mouse (Ch. 2) and at Karagailibulak R. (Ch. 1) Parameters 2 Area (km ) Perimeter (km) Mean elevation (m) Mean slope (grad) -1 Mean curvature of surface(км ) Mean exposition о Mean annual air temperature ( С) Mean annual precipitation (mm) Mean annual potential evaporation (mm) Mean annual evapotranspiration (mm) without melioration loss Mean annual river runoff (mm) 3 Mean annual volume of runoff (км ) Mean humidification (P/E*) 2 Glacier covered areas (km ) 2 Lake areas (km ) 2 Rock areas (km ) 2 Areas of water-logged ground (km ) 2 Forest areas (km ) 2 Bush covered areas (km ) 2 Garden covered areas (km ) 2 Meliorated areas (km )
Ch. 1 1037.33 193.99 3412 12.6 -0,00123 0.915 -3.6 809 719 379 430 0.446 1.17 134.01 0.48 49.30 0.50 13.65 0.97
Ch. 2 1815.31 307.97 3006 12.2 +0,00049 0.915 -1.9 729 771 392 337 0.612 1.00 135.67 0.76 69.46 0.77 68.90 4.77 0.60 66.27
Table 4. Correlation coefficients between calculated –measured discrepancies and different parameters
Parameters Ti Pi Bi Ri-1 Ri-1+Ri-2 Ri-1+Ri-2+Ri-3 Ri-1+Ri-2+Ri-3+R-i-4 Ri-1+Ri-2+Ri-3+Ri-4+Ri-5 R0 (li) ' R (li) R0 (sq) '' R0 (sq) Pi-1 Pi-2 Pi-3 Pi-4 Pi-5 Pi-1+Pi-2 Pi-1+Pi-2+Pi-3 Pi-1+Pi-2+Pi-3+Pi-4 Pi-1+Pi-2+Pi-3+Pi-4+Pi-5 P0 (li) ' P (li) P0 (kv) '' P0 (kv)
Ch. 1 -0.19 0.76 0.09 -0.15 -0.14 -0.02 -0.08 -0.05 0.57 0.71 0.20 0.45
7
Ch. 2 -0.25 0.82 0.29 -0.27 -0.35 -0.25 -0.32 -0.29 0.48 0.76 0.12 0.47
Ch1+2 -0.13 0.50 0.20 -0.21 -0.23 -0.13 -0.17 -0.14 0.40 0.74 0.12 0.46 -0.21 -0.10 -0.03 -0.10 -0.03 -0.18 -0.11 -0.12 -0.09 0.17 0.73 0.01 0.48
Table 5. Residual mean square errors (km3) of approximating the discrepancy in annual runoff Parameters P B R0 ' R0 '' R0 P B P R0 ' P R0 '' P R0 B R0 ' B R0 '' B R0 ' R0 R0 '' R0 R0 ' '' R0 R0
Ch. 1 0,075 0,115 0,095 0,082 0,104 0,061 0,073 0,068 0,072 0,095 0,082 0,103 0,049 0,059 0,070
Ch. 2 0,085 0,142 0,130 0,096 0,131 0,081 0,084 0,074 0,082 0,126 0,093 0,124 0,064 0,087 0,074
Ch. 1+2 0,115 0,130 0,122 0,089 0,118 0,115 0,115 0,085 0,106 0,120 0,088 0,115 0,072 0,095 0,072
Parameters P B R0 ' P B R0 '' P B R0 ' P R0 R0 '' P R0 R0 ' '' P R0 R0 ' B R0 R0 '' B R0 R0 ' '' B R0 R0 ' '' R0 R0 R0 ' P B R0 R0 '' P B R0 R0 ' '' P B R0 R0 ' '' P R0 R0 R0 ' '' B R0 R0 R0 ' '' P B R0 R0 R0
Ch. 1 0,061 0,059 0,061 0,048 0,058 0,064 0,049 0,059 0,070 0,049 0,046 0,058 0,057 0,048 0,049 0,046
Ch. 2 0,080 0,073 0,079 0,064 0,079 0,067 0,063 0,085 0,073 0,061 0,059 0,079 0,067 0,061 0,060 0,057
Ch. 1+2 0,115 0,085 0,105 0,060 0,092 0,072 0,071 0,093 0,072 0,066 0,054 0,086 0,072 0,058 0,066 0,054
Figure 5 Corrections to the values of annual precipitation (Pi), mass balance (Bi), and river runoff for the previous year (Ri-1; R’i-1) in simulation of river runoff (a), and the cumulative values of corrections of river runoff for the previous year (b) in two Chon Kemin River basin (Ch.1, 2). a Ch.1
Corrections (km3) 0.4
Pi
Bi
Ri-1
0.2 0 -0.2 -0.4 -0.6 1957
1961
1965
1969
1973
1977
1981
1985
1989
1993
Years
a Ch. 2
Corrections (km3) 0.4 0.2 0 -0.2 -0.4 -0.6
1957
1961
1965
1969
1973 Years
8
1977
1981
1985
1989
1993
b
Cum. correction to the values (km3) 1.8 1.4 1 0.6
Chk1
Chk2
0.2 -0.2 1957
1961
1965
1969
1973 1977 Years
1981
1985
1989
1993
Figure 6. Measured, simulated and corrected annual river runoff in two Chon Kemin River basins.
Annual runoff (km3)
Ch. 1
0.9
Measured
0.8
Simulated
Corrected
0.7 0.6 0.5 0.4 0.3 0.2 1957
1961
1965
1969
1973
1977
1981
1985
1989
1993
Year
Ch. 2
Annual runoff (km3) 1.2 1.1 1 0.9 0.8 0.7 0.6 0.5 0.4 0.3 1957
1961
1965
1969
1973 1977 Years
1981
1985
1989
1993
3.4. Water balance components assessment.
from 1100 mm to 600 mm and simultaneous increase of
Changes in water balance components from 1957 to
potential evaporation up to 800 mm (Fig. 7) observed at
1995 shown on the Fig. 7 revealed no significant
th the beginning of 70 caused the observed depletion of
trend in their variability. Most variable characteristics
aquifer (Fig. 5b). Mean annual evapotranspiration a little
are precipitation and potential evaporation ranging
higher there than river runoff in basin almost for all
closed each other that pointed on stability of index of
period,
moisture in the basin equaled around 1.0 (i.e., 0.95,
precipitation (Table 8, Fig.7).
Table 8). Abrupt decrease in the annual precipitation
9
compounding
about
half
of
the
basin
Figure 7 Simulated and corrected water balance components the Chon Kemin R. (Ch.1) Layer w.e. (mm) 1300 1100 900 700 500 300 100
Precipitation
Potencial evaporation
Evapotranspiration
Loss for irrigation
Glacier mass balance
River runoff
-100 1957
1961
1965
1969
1973 1977 Years
1981
1985
1989
1993
Figure 8. Predicted changes in the current river runoff (R/Rc) (a) and index of moisture conditions (D=P/E*) in the Chon Kemin River basin under the different scenarios of climatic changes (T = Tc +dT; P = mPc). R and Rc are predicted and current river runoff; T and Tc are possible and
2.2 2
Index of moistur, P/E*
River runoff (share from present)
current air temperatures; P and Pc are predicted and current precipitation.
1.8 1.6 1.4 1.2 1 0.8 0.6 0.4 0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
1.5 1.4 1.3 1.2 1.1 1 0.9 0.8 0.7 0.6 0.5 0.4 0
0.5
Changes in air temperatures (0C)
1
1.5
2
2.5
3
3.5
4
4.5
5
Changes in air temperatures (0C)
m=0,8
m=0,9
m=1,0
m=1,1
m=1,2
m=1,3
m=1,4
m=1,5
m=0,8 m=1,2
m=0,9 m=1,3
m=1,0 m=1,4
m=1,1 m=1,5
3.5. Prediction of river runoff and index of moisture.
will be increasing, e.g., more than 1.25 times of the
Hypothetical climate-change scenarios in Tien Shan
present (Fig. 8a). Only in case if we assume boundary
modeled as a stepwise progression predict an increase in
conditions, e.g., increase in air temperature of 4.4ºC and
о
air temperature of 1.8ºC to 4.4ºC (i.e., on average 3 С)
decrease of precipitation 0.94, than the river runoff in Tien
and precipitation at 0.94 to 1.54 times (1.2 times) during
Shan basins may decrease respectively 0.62 times due to
the XXI Century, which will lead to a increase of river
increase evapotranspiration by 1.11 times (Table 6).
runoff by 1.047 times. Index of moisture would decrease
Index of moisture would decrease from 0.95 to 0.54 under
from 0.95 (present state) to 0.82. River runoff will not drop
the
o
even under the air temperature rise on 5 C if precipitation
closed
to
desertification.
10
threshold
conditions
of
irreversible
Table 6. Predicted water balance components under different scenarios of climate change. T is air temperature, Tc is current long-term mean air temperature; P is annual amount of precipitation, Pc is current long-term mean annual amount of precipitation T=Tc P=Pc·0.8
P= Pc·0.9
P= Pc·1.0
P= Pc·1.1
P= Pc·1.2
P= Pc·1.3
P= Pc·1.4
P= Pc·1.5
T, °C P, mm(km3) E*, mm D=P/E* E, mm(km3) R, mm(km3) R/Rc T, °C P, mm(km3) E*, mm D=P/E* E, mm(km3) R, mm(km3) R/Rc T, °C P, mm(km3) E*, mm D=P/E* E, mm(km3) R, mm(km3) R/Rc T, °C P, mm(km3) E*, mm D=P/E* E, mm(km3) R, mm(km3) R/Rc T, °C P, mm(km3) E*, mm D=P/E* E, mm(km3) R, mm(km3) R/Rc T, °C P, mm(km3) E*, mm D=P/E* E, mm(km3) R, mm(km3) R/Rc T, °C P, mm(km3) E*, mm D=P/E* E, mm(km3) R, mm(km3) R/Rc T, °C P, mm(km3) E*, mm D=P/E* E, mm(km3) R, mm(km3) R/Rc
-1.90 583(1.059) 773 0.754 393(0.715) 189(0.344) 0.625 -1,90 656(1.191) 772 0.850 413(0.750) 242(0.441) 0.802 -1.90 729(1.324) 770 0.946 426(0.773) 303(0.550) 1.000 -1.90 802(1.456) 769 1.042 433(0.787) 368(0.669) 1.216 -1.90 875(1.588) 768 1.139 437(0.794) 437(0.795) 1.444 -1.90 948(1.721) 767 1.235 438(0.795) 509(0.926) 1.682 -1.90 1020(1.853) 767 1.331 436(0.792) 584(1.061) 1.928 -1.90 1093(1.985) 766 1.427 433(0.787) 660(1.199) 2.179
T= Tc +1°C -0.90 583(1.059) 871 0.669 412(0.749) 170(0.310) 0.563 -0.90 656(1.191) 869 0.754 440(0.799) 216(0.393) 0.713 -0.90 729(1.324) 868 0.840 459(0.835) 269(0.489) 0.888 -0.90 802(1.456) 866 0.925 473(0.859) 328(0.597) 1.084 -0.90 875(1.588) 865 1.011 481(0.874) 393(0.714) 1.297 -0,90 948(1.721) 864 1.096 486(0.883) 461(0.838) 1.523 -0.90 1020(1.853) 864 1.182 487(0.886) 532(0.967) 1.758 -0.90 1093(1.985) 863 1.267 487(0.884) 606(1.101) 2.001
T= Tc +2°C 0.10 583(1.059) 977 0.597 424(0.771) 158(0.288) 0.523 0.10 656(1.191) 975 0.673 459(0.834) 196(0.357) 0.649 0.10 729(1.324) 973 0.749 487(0.885) 241(0.439) 0.798 0.10 802(1.456) 972 0.825 508(0.922) 294(0.534) 0.970 0.10 875(1.588) 971 0.901 522(0,949) 352(0,639) 1.162 0.10 948(1.721) 970 0.977 532(0.967) 415(0.754) 1.370 0.10 1020(1.853) 969 1.053 538(0.977) 482(0.876) 1.592 0.10 1093(1.985) 968 1.130 540(0.982) 552(1.004) 1.824
4. CONCLUSION The
major
water
T= Tc +3°C 1.10 583(1.059) 1092 0.534 432(0.786) 150(0.273) 0.496 1.10 656(1.191) 1090 0.602 472(0.857) 184(0.334) 0.607 1.10 729(1.324) 1088 0.670 507(0.920) 222(0.403) 0.733 1.10 802(1.456) 1086 0.738 535(0.972) 266(0.484) 0.879 1.10 875(1.588) 1085 0.806 557(1.012) 317(0.576) 1.047 1,10 948(1.721) 1083 0.875 574(1.042) 373(0.679) 1.233 1.10 1020(1.853) 1082 0.943 585(1.063) 435(0.790) 1.436 1.10 1093(1.985) 1081 1.011 592(1.076) 501(0.910) 1.653
T= Tc +4°C 2.10 583(1.059) 1216 0.480 439(0.798) 143(0.261) 0.474 2.10 656(1.191) 1213 0.541 480(0.873) 175(0.318) 0.579 2.10 729(1.324) 1211 0.602 519(0.943) 209(0.381) 0.692 2.10 802(1.456) 1209 0.663 554(1.007) 247(0.449) 0.816 2.10 875(1.588) 1207 0.725 584(1.061) 290(0.527) 0.958 2.10 948(1.721) 1206 0.786 608(1.104) 339(0.616) 1.120 2.10 1020(1.853) 1205 0.847 626(1.138) 394(0.715) 1.300 2.10 1093(1.985) 1204 0.908 640(1.162) 453(0.824) 1.497
T= Tc +5°C 3.10 583(1.059) 1348 0.432 446(0.810) 137(0.249) 0.453 3.10 656(1.191) 1345 0.488 488(0.887) 167(0.305) 0.554 3.10 729(1.324) 1343 0.543 528(0.960) 200(0.364) 0.662 3.10 802(1.456) 1341 0.598 566(1.029) 235(0.427) 0.776 3.10 875(1.588) 1339 0.653 602(1.093) 272(0.495) 0.899 3.10 948(1.721) 1338 0.708 633(1.150) 314(0.570) 1.037 3.10 1020(1.853) 1336 0.764 659(1.197) 361(0.656) 1.191 3.10 1093(1.985) 1335 0.819 680(1.235) 413(0.751) 1.364
Shan relief using rectangular coordinates of the cycle
characteristics
and
equivalent cone projection with standard parallels and
components (air temperature, precipitation, potential
1:500,000 scale Digital Elevation Model with 100-m grid
evaporation, evapotranspiration, and river runoff)
resolution of that covers 800,000 knotted points.
were digitized through developed simulation over Tien
11
Digitized account
evapotranspiration
air
temperature,
model
took
precipitation,
into
evapotranspiration with consecutive intensifying of re-
and
evaporated moisture precipitated in mountains that
topography (angle, exposition, curvature of a surface).
relatively
Applicable GIS-based distributed River Runoff Model
temperature.
should
suppress
the
increase
in
air
was implemented in regional conditions testing in two sub-basins of the Chon Kemin R. basin, using method
4. ACKNOWLEDGEMENTS
of transition from large to smaller geographic units
This research was supported by NSF grant ATM –
(downscale information transfer) taking into account
0233583.
glacier mass balance, forest covered lands and
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