Snow and glaciermelt runoff modeling in Upper Indus Basin of Pakistan
Maheswor SHRESTHA*Researcher, Department of Civil Engineering,
University of Tokyo, JAPAN
7th GEOSS Asia Pacific SymposiumGEOSS AWCI Parallel Session:
26-28 May, 2014, Tokyo, Japan
Inter-linkage case study in Pakistan
Indus Basin - Resources Nexus
Indus Water Treaty 1960 Source: WAPDA
Snow/GlacierSource: Rasul, PMD
Indus Basin - Resources Nexus
Snow/Glacier : Upper Indus
Climate Change:
How the equilibrium of this nexus will be affected ?
Rainfall : Middle-Lower Indus
Modeling systemWhich model?
Tropical – Arctic,Dry – Wet, Low-High elevationVariety of Landuse
Land Use and Land Cover Map of Indus Basin (Cheema and Bastiaanssen, 2012)
Physics Based Distributed Hydrological ModelRainfall induced flow (Land/Snow/Glacier/Forest)Snowmelt induced flow (Land/Glacier/Forest)Glacier melt induced flowCombination of All
Snow/Glacier-Soil-Vegetation-Atmosphere-Transfer(SSVAT) schemes in land surface and hydrologic models
Hydrological ModelWater and Energy budget based distributed hydrological model withimproved snow and glacier schemes (WEB-DHM-S)
Shrestha et al., 2010, 2012, 2013
One layer Snow physics
Empirical albedo
Snow over Bare Land
Soil
Snow /water
Rswαc.Rsw
(αc,δc,εc )
δc.RswαsδcRsw
Rlw εcσTc4
(1-εc)Rlw εcσTc4
Canopy
Tc
SWtransmittance
σTsn(Z3)4
Snow
Snow over Forest region
Clean Glacier
Debris Covered Glacier
Clean/Debris Covered Glacier
Glaciers Covered with Snow
Upper Indus Basin (200700 km2)Grid size: 1 km
# 6
82°
82°
80°
80°
78°
78°
76°
76°
74°
74°
72°
72°
38° 38°
36° 36°
34° 34°
32° 32°
30° 30°
Pakistan
India
China
Indus River
Upper Indus Basin
Tarbela Dam
DEM
High : 7647
Low : 406
Karakoram Sub-basinsHUNZA
Himalaya
Glacier : About 22000 km2
# 7
Data Set
Gauge Data – WAPDAMax/Min air temperaturePrecipitationTotal solar radiation
APHRODITE gridded precipitation data (25 km)
Global Land Data Assimilation System (GLDAS) data (25 km)
Specific HumidityShortwave radiationWind speed
Glacier Cover dataICIMOD (Bajracharya et al., 2011)
Hunza Basin (13733 km2)
Hunza Basin Snow/Glacier Cover Area
# 8
Snow/Glacier State simulation (2001-2002)
January 1 May 9 July 12 September 14
Legend: 1 2 3 4 5 6
1: Land, 2: Clean glacier, 3: Debris
4: Snow over clean glacier, 5: Snow over debris, 6: Snow over land
(b) Areal extent of snow cover
0.0
0.2
0.4
0.6
0.8
1.0
8-O
ct
24
-Oct
9-N
ov
25
-Nov
11
-Dec
27
-Dec
9-J
an
25
-Jan
10
-Feb
26-F
eb
13
-Mar
29
-Mar
14
-Apr
30
-Apr
16
-May
1-J
un
17
-Jun
3-J
ul
19
-Jul
4-A
ug
20
-Aug
5-S
ep
21-S
epSn
ow
Co
ver
Are
a (i
n f
ract
ion
)MODIS
MODEL
Absolute BIAS
(c) Pixel-by-Pixel Analysis
LandSnow over Land
Clean glacierSnow over clean glacier
Debris covered glacierSnow over debris glacier
LandSnow over Land
Clean glacierSnow over clean glacier
Debris covered glacierSnow over debris glacier
LandSnow over Land
Clean glacierSnow over clean glacier
Debris covered glacierSnow over debris glacier
(a) Spatial distribution of snow cover area (2003-2004)
MODIS Model MODIS Model
November 9 January 1
March 5 May 9
July 11 September 13 Legend: Land, Snow, Cloud
Hunza Basin Daily Discharge
# 9
Snow & glacier melt contribution = 80-85 % (50-60% snowmelt)Rainfall contribution = 15-20%
Calibration Validation
Upper Indus Basin (200700 km2)Grid size: 1 km
# 10
82°
82°
80°
80°
78°
78°
76°
76°
74°
74°
72°
72°
38° 38°
36° 36°
34° 34°
32° 32°
30° 30°
Pakistan
India
China
Indus River
Upper Indus Basin
Tarbela Dam
Simulation results follows the seasonal variation of snow cover represented by the MODIS
However, large discrepancies were observed while performing pixel-pixel analysis, mainly due to the uncertainty in spatial distribution of APHRODITE precipitation.
Snow Cover Area
Indus Basin (200700 km2) Daily Discharge
# 11
Long-term simulation 1980-2012 is ongoing with the use of JRA55 dataset.
Daily Discharge
Climate ChangeIssue on Bias correction of Snowfall in Large scale
# 12
Long-term
Snowfall data
???
Past
GCM Precipitation
Bias Correction
Estimate Function
Future
GCM
Precipitation
Access Impacts on
Water resources, Food, Energy
via various Modelling tools
Reanalysis Data
• Coarse
• Bias
Distributed Snow
and Glaciermelt
ModelObs vs Sim Snow
cover and Runoff
Correct
Reanalysis
Data
Summary & Outlook
# 13
A Comprehensive Modeling system has been established which can
simulate the Snow processes and Glacier processes and Forest snow
processes simultaneously in a basin scale. The model has been well
implemented in the Upper Indus Basin.
Validation of the model in Upper Indus basin will be carried out
following long term simulation (30 yrs). Finally, impact of climate
change will be assessed.
Inter-linkage of variability in flow of upper Indus basin to the lower
region will be addressed. Impact on irrigation, energy and socio-
economic parameters will be studied through regional cooperation
among different institutions and agencies.
Thank you !!
