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 Source: Rasul, PMD Snow/Glacier Indus Water Treaty 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 Rainfall induced flow (Land/Snow/Glacier/Forest) Snowmelt induced flow (Land/Glacier/Forest) Glacier melt induced flow Combination of All Snow/Glacier-Soil-Vegetation- Atmosphere-Transfer (SSVAT) schemes in land surface and hydrologic models
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 Debris Covered Glacier Glaciers Covered with Snow One layer Snow physics Empirical albedo Snow over Bare Land α c.r sw Snow /water Canopy (α c,δ c,ε c ) R sw R lw ε c σt c 4 T c (1-ε c )R lw ε c σt c 4 α s δ c R sw δ c. R sw σt sn(z3) 4 Clean/Debris Covered Glacier SW transmittance Snow Soil Snow over Forest region
# 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 Tarbela Dam 34 Pakistan 32 32 Indus River India 30 30 Glacier : About 22000 km 2 72 74 76 78 80 82 Karakoram DEM HUNZA Sub-basins 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-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 Snow Cover Area (in fraction) # 8 Hunza Basin Snow/Glacier Cover Area Snow/Glacier State simulation (2001-2002) Land Snow over Land Land Clean glacier Snow over Land Snow over clean glacier January 1 May 9 July 12 September 14 Legend: 1 2 3 4 5 6 (a) Spatial distribution of snow cover area (2003-2004) 1: Land, 2: Clean glacier, 3: Debris MODIS Model MODIS Model 4: Snow over clean glacier, 5: Snow over debris, 6: Snow over land Land Snow over Land Clean glacier Snow over clean glacier Debris covered glacier Snow over debris glacier Clean Snow November 9 January 1 1.0 0.8 0.6 (b) Areal extent of snow cover MODIS MODEL Absolute BIAS 0.4 March 5 May 9 0.2 0.0 July 11 September 13 Legend: Land, Snow, Cloud (c) Pixel-by-Pixel Analysis
# 9 Hunza Basin Daily Discharge Calibration Validation Snow & glacier melt contribution = 80-85 % (50-60% snowmelt) Rainfall contribution = 15-20%
# 10 72 74 76 78 80 82 Upper Indus Basin (200700 km 2 ) Grid size: 1 km Snow Cover Area 38 38 Upper Indus Basin China 36 36 34 Tarbela Dam 34 Pakistan 32 32 Indus River India 30 30 72 74 76 78 80 82 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 Coarse Bias Long-term Snowfall data??? Past GCM Precipitation Distributed Snow and Glaciermelt Model Obs vs Sim Snow cover and Runoff Bias Correction Estimate Function Future GCM Precipitation Correct Reanalysis Data Access Impacts on Water resources, Food, Energy 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 socioeconomic parameters will be studied through regional cooperation among different institutions and agencies. Thank you!!