7 th GEOSS Asia Pacific Symposium GEOSS AWCI Parallel Session: 26-28 May, 2014, Tokyo, Japan Inter-linkage case study in Pakistan Snow and glaciermelt runoff modeling in Upper Indus Basin of Pakistan Maheswor SHRESTHA *Researcher, Department of Civil Engineering, University of Tokyo, JAPAN
Indus Basin - Resources Nexus Snow/Glacier Source: Rasul, PMD Indu ndus Water ter Trea eaty ty 1960 1960 Source: WAPDA
Indus Basin - Resources Nexus Rainfall : Middle-Lower Indus Snow/Glacier : Upper Indus Climate Change: How the equilibrium of this nexus will be affected ?
Modeling system Which model? Land Use and Land Cover Map of Indus Basin (Cheema and Bastiaanssen, 2012) Tropical – Arctic, Dry – Wet, Low-High elevation Variety of Landuse Physics Based Distributed Hydrological Model Snow/Glacier-Soil-Vegetation- Rainfall induced flow (Land/Snow/Glacier/Forest) Atmosphere-Transfer Snowmelt induced flow (Land/Glacier/Forest) (SSVAT) schemes in land Glacier melt induced flow surface and hydrologic models Combination of All
Hydrological Model Water and Energy budget based distributed hydrological model with improved snow and glacier schemes (WEB-DHM-S) Shrestha et al., 2010, 2012, 2013 Clean Glacier Snow over Bare Land One layer Snow physics R lw ε c σ T c α c .R sw 4 R sw Debris Covered Glacier Empirical albedo Glaciers Covered Snow /water with Snow Canopy ( α c , δ c , ε c ) T c (1- ε c )R lw ε c σ T c 4 α s δ c R sw δ c. R sw σ T sn(Z3) 4 SW transmittance Snow Soil Snow over Forest region Clean/Debris Covered Glacier
# 6 Upper Indus Basin (200700 km 2 ) Grid size: 1 km 72° 74° 76° 78° 80° 82° 38° 38° Upper Indus Basin China 36° 36° 34° 34° Tarbela Dam Pakistan 32° 32° India Indus River Glacier : About 22000 km 2 30° 30° 72° 74° 76° 78° 80° 82° HUNZA Karakoram Sub-basins DEM High : 7647 Low : 406 Himalaya
# 7 Hunza Basin (13733 km 2 ) Data Set Gauge Data – WAPDA Max/Min air temperature Precipitation Total solar radiation APHRODITE gridded precipitation data (25 km) Global Land Data Assimilation System (GLDAS) data (25 km) Specific Humidity Shortwave radiation Wind speed Glacier Cover data ICIMOD (Bajracharya et al., 2011)
# 8 Hunza Basin Snow/Glacier Cover Area Snow/Glacier State simulation (2001-2002) L Sno Clea Sno De Sno January 1 May 9 July 12 September 14 1 2 3 4 5 6 (a) Spatial distribution of snow cover area (2003-2004) MODIS Model MODIS Model (b) Areal extent of snow cover 1.0 Snow Cover Area (in fraction) MODIS MODEL January 1 November 9 0.8 Absolute BIAS 0.6 0.4 0.2 May 9 March 5 0.0 8-Oct 24-Oct 9-Nov 25-Nov 11-Dec 27-Dec 9-Jan 25-Jan 10-Feb 26-Feb 13-Mar 29-Mar 14-Apr 30-Apr 16-May 1-Jun 17-Jun 3-Jul 19-Jul 4-Aug 20-Aug 5-Sep 21-Sep (c) Pixel-by-Pixel Analysis September 13 July 11 Legend: Land, Snow, Cloud
# 9 Hunza Basin Daily Discharge Validation Calibration Snow & glacier melt contribution = 80-85 % (50-60% snowmelt) Rainfall contribution = 15-20%
# 10 72° 74° 76° 78° 80° 82° 38° 38° Upper Indus Basin China Upper Indus Basin (200700 km 2 ) 36° 36° 34° 34° Tarbela Dam Pakistan Grid size: 1 km 32° 32° India Indus River 30° 30° 72° 74° 76° 78° 80° 82° Snow Cover Area 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.
# 11 Indus Basin (200700 km 2 ) Daily Discharge Daily Discharge Long-term simulation 1980-2012 is ongoing with the use of JRA55 dataset.
# 12 Climate Change Issue on Bias correction of Snowfall in Large scale Reanalysis Data Long-term Past Coarse Snowfall data GCM • Bias ??? Precipitation • Bias Correction Distributed Snow Estimate Function and Glaciermelt Model Future GCM Obs vs Sim Snow Precipitation cover and Runoff Correct Access Impacts on Reanalysis Water resources, Food, Energy Data via various Modelling tools
# 13 Summary & Outlook 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 !!
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