Transcript Analysis of the hydrophysical processes of the Aral sea

Analysis of the hydrophysical processes of the
Aral sea dessicationon on the basis of the
historical data and numerical modelling
Ac. O.F.Vasiliev, Prof. V.I.Kuzin,
Prof. V.I.Kvon
Institute of Water & Environmental Problems
Institute of Computational Mathematics &
Mathematical Geophysics
SD RAS, Novosibirsk
PROJECT: REBASOWS, INTAS 01-0511
The rehabilitation of ecosystem and bioproductivity of
part water body of the Aral Sea under conditions of water
scarcity
• Research Goal:
• Forecast of the future Aral Sea water and salt balance
under different scenarios of water inflow to the Aral
coastal zone;
• Definition of sustainable ecological profile of close water
body and selection of the strategy of possible ecosystem,
biodiversity and bioproductivity restoration in the part of
the Aral Sea
• Teams:
• Austria (2), Uzbekistan (2), Russia (1)
Amu Darya, Syr Darya basins
Aral Sea Basin XX Cent.
Flow
(km3),
Level
(m),
Area
(103 km2)
80
8
70
7
60
Irrigated
Land
6
50
Area
5 Irrigated
Level
40
4
30
3
Flow
20
2
10
1
0
1930
1940
1950
1960
1970
1980
1990
0
2000
Land
(106 ha)
Hydrological changes in the Aral Sea basin
Degradation of Hydrologic System of the Aral Sea Basin
Runoff (km3/year)
Total
At mouth (in past)
Rivers
Length
km
Basin Area
(km2)
Amu Darya
2 620
465x103
79,5
42
Syr Darya
3 078
462x103
37,2
14
Σ=116,7
Σ=56
THE ARAL SEA BEHAVIOUR
Large Aral
1960
1985
1987
2000
Level (m)
53,50
41,95
40,19
33,50
Surface Area (km2)
68478
44382
40297
19071
Volume (km3)
1093
475
414,1
131
Aral Sea basin runoff and Aral Sea Inflow
(1989 – 2000)
130
120
Basin Runoff
Aral Inflow
110
Runoff and Inflow (km3)
100
90
80
70
60
50
40
Amount
being used
for Irrigation
30
20
10
0
1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000
Satellite image of the Amu-Dar’ja, Syr-Dar’ja Dealtas ( Resurs-01, 1995)
Environment: The Aral Sea was once the fourth biggest inland sea in
the world. With abundant fish resources, and a busy shipping trade
between its northern port of Aralsk and the river ports of the AmuDarja, some as far distant as Tajikistan, the Sea provided a healthy
livelihood for several hundred thousand people. The Aral Sea surface
was 66,100 square kilometers with an average depth of 16,1 meters
and a maximum depth of 68 meters. Salt content was 10 g/l. Then in
the sixties, the flow of water into the Sea began to drop alarmingly.
Upstream irrigation schemes, for the growing of rice and cotton,
consumed like a sponge more than 90 per cent of the natural flow of
water from the Tian Shan mountains. As a result the Sea's surface
area declined. 27,000 square kilometers of former sea bottom became
dry surface. About 80% of water volume was lost. The sea level
declined 14 meters. Salt concentration increased. Today, an
estimated 200,000 tones of salt and sand are being carried away by
wind and discharged within a radius of 300 km every day. Because of
the dying out of the sea as well as the usage of large areas for
military and space centers, important climatic changes have taken
place. During the last ten years these changes have become
especially visible. The salt polluted air is carried away by the wind
from the now dried-up salt lakes and former sea bottom
Image of the Aral Sea region from the satellite, 1998
Irrigation net of the Amu Dar’ja (8000 channels & collectors)
Land use in the Amu Dar’ja delta (cotton-yellow, rise-green)
Phenology in the Amu-Dar’ja Delta
Bathymetry of the Aral Sea, 1960, 1997
Main events:
 1960 - intensification of the Amu Darja, Syr Darja water use for
irrigation purposes
 1989 - separation of the Northern and Central Aral basins
 2000 - connection of the Lazarev, Vozrogdenija islands with mainland
and formation of single Peninsula which separate the Western (deep) and
Eastern (shallow) basins with connection only in the northern part
Resulting:
- Aral sea level height decreased from 53 m to 31.5 m (Baltic
system);
- Aral Sea lost 80% of water volume;
80% of sea surface;
- salinity increased from 10 to 20-50 g/l.
Possible Ways for rehabilitation of the Aral Sea:
-Reducing the 70% of Amy Darja water amount for irrigation
which will increase the Aral Sea level to 38.5 m (unrealistic);
- Separation of the Western and Eastern parts and keep only one of
them with reducing 30-40% water for irrigation.
Chronology of the dessication of the Aral Sea
The dessication of the Aral sea from 1995 to 1996
1995
1996
Difference
Concequences of the Aral Sea dessication
Climatic consequences
Mesoclimatic
changes (increase of
continentality)
Ecological / economic
consequences
Health consequences
Degeneration of the
delta ecosystems
Increase of serious
diseases( e.g. cholera,
typhus, gastritis, blood
cancer)
Total collapse of the Increase of respiratory
Increase of salt and
fishing industry
system diseases
dust storms 2 mln t/y
(originally 44 th. t/y) (asthma, bronchitis)
Shortening of the
vegetation period
Decrease of
productivity of
agricultural fields
Birth defects and high
infant mortality
Health: The drying-up of the Sea, and the salt and dust laden
air, have had a damaging effect on the health of the people,
and the animal and plant life as well. The introduction of
pesticides into the rice and cotton fields, and the seepage of
the residues back into the rivers, has heavily contaminated the
water for those communities living along the banks of the
rivers flowing into the Sea. This has further aggravated
people's health. Diseases like anemia, cancer and
tuberculosis, and allergies are frequent. Many children are
born with defects. Also in the years since the first project was
implemented, there has been a continued increase in Typhoid
fever, viral hepatitis, TB, and throat cancer in many areas as
high as three times the national average. All of these
complaints can be attributed either to the reduction in quality
and quantity of water resulting from the drying up of the Aral
Sea of the spread of toxic dusts and deterioration of the
regional climate resulting from the Aral Sea disaster.
Climatic temperature 1960-1990, January (top), June (bottom)
International cooperation and projects
- Climatic changes in Aral Sea region - Copernicus Grant
(Uzbekistan, Bulgaria, Germany, Ukraine)
- Development of a GIS for optimization of land and water use in the
Amu-Darja Delta (sponsored by NATO Science Division Affairs);
- Program of developing of water resources allocation tools for use in
the Aral Sea basin - Center for Research in Water Recourses of Texas
University in Austin (funded by US Agency for International
Development);
- Central Asia Center (John Hopkins)
Central Asia Regional Water, Environment and Energy
Agreements
Framework Agreements:

Agreement Between the Republic of Kazakhstan , the
Republic of Kirgyzstan, the Republic of Uzbekistan, the Republic
of Tajikistan and Turkmenistan On Cooperation in the Field of
Joint Water Resources Management and Conservation of Interstate
Sources
Types of models which are planning to use
• Integral Aral Sea models (bulk models on the basis of the
•
•
•
•
•
conservation lows for mass and salt);
Quasi-two dimensional model integrated by the width of
the basin (x-z coordinate);
Tree dimensional thermo-hydrodynamic model;
Chemical processes integrated model;
Biological model,
Coupled regional climatic Central Asia atmosphere-Aral
Sea model.
Simulation of the Amu Darja inflow for 20 years km3 (top),
Simulation of the Amu Darja mineralization g/l (bottom)
25
20
15
Опт.вариант
10
Сущ.тенденция
5
0
1
2
3
4
5
6
7
8
9 10 11 12 13 14 15 16 17 18 19 20
30
25
Опт.вариант
20
Сущ.тенденция
15
10
1
2
3
4
5
6
7
8
9 10 11 12 13 14 15 16 17 18 19 20
Modeling of hydrodynamic, hydrophysical and hydrochemical
processes
The 3D ICM&MG Aral Sea circulation model
There are two versions of the Aral Sea circulation model developed in the
Laboratory of the Mathematical Modeling of the Hydrosphere of ICM&MG SD
RAS. The models differ in the method of the vertical levels distribution: the
sigma-coordinate model and the z-coordinate model.
The authors of the models are Prof. V.I.Kuzin, Dr. E.N.Golubeva.
An essential difference in the bottom relief of the Western and Eastern parts of the
Aral Sea causes some difficulties in the simulation with the unique version of the
vertical grid. Thus, in the Western Part of the Sea, z-coordinate multilevel model is
more preferable.
The sigma-coordinate model will be used for the Eastern Part. In the present
version of the model, two parts have no connection between themselves.
At the first stage, z-coordinate version of the model was adopted for the Western
Part of the Aral Sea what is in agreement with one of the scenarios of the project.
The numerical model has a horizontal grid with 500*500 m resolution.
The vertical non-uniform grid is used (35 levels for the maximum depth).
General features of the models are as follows:

Mathematical model is based on the complete “primitive” nonlinear
equations of the thermo-hydrodynamics of the ocean;

Temperature and salinity distributions are calculated;

The models have a possibility to include the calculation of
pollutants;
 The interaction with the atmosphere is realized via the upper mixed
layer with the possibility to include the ice formation;

The models have a possibility to include inflows and outflows from
the basin;
 The models are based on a combination of the finite element and
splitting methods;

The triangulated quasi-regular B-grid is used in the models, which
enables one to easily change the configuration of basin;

The models differ in the method of the vertical levels distribution:
the sigma-coordinate model and the z-coordinate model.
T
Aral Sea bathymetry At the level 31.5 m (left), Western Part (right)
Left:
a)The vertical cross-section of the Aral Sea along the latitude;
в) schematic representation of the sigma-coordinate grid;
с) schematic representation of z-grid.The depth is given in meters.
Preliminary experiment. Velocity field at a depth of 3 m (center), 9 m (right).
depth (m)
0
20
100
40
a)
depth (m)
depth (m)
60
0
1
2
3
4
5
6
7
8
0
1
2
3
4
5
6
7
8
0
50
100
150
200
250
300
100
90
350
90
80
80
70
70
60
b)
0
50
100
150
60
50
200
50
40
40
30
30
20
c)
0
50
100
150
20
10
200
0
10
0
10
20
30
40
0
0
10
20
30
40
50
Conclusions:
• Processes in the Aral Sea region during the last 40 years is one of the
•
•
•
•
most drastic example of of the possible consequence of man-induced
environmental changes
The Aral Sea dessication changed the regional climate and initiate the
problems in ecology, agriculture, fishery, industry, health and social
conditions;
For the rehabilitation of the Aral Sea the level should be increased
from 31.5 m to 38.5 m, or western and Eastern basins should be kept
separately;
Recommendation to Central Asia Governments can be done on the
basis of the use of the multi-objective water resource models of
different levels: integral Aral Sea models, hydrological optimization
models, quasi-2D models, 3D Aral Sea models, coupled Aral region
regional climatic-sea models, biological models etc.;
Solution of the Aral Sea problem can be found only on the basis of the
Agreement on the Water Resources Management between the Central
Asia States.