Glacier changes in the Western Karakoram Himalaya

1. Glacier changes in the Western Karakoram Himalaya Bibi S. Naz 03/10/2009

2. Source: IPCC Report 2007 Atmospheric CO2 (ppm) Law Dome ice core Etheridge et al (1999) Time (100 years) Global climate change

3. Changes in the precipitation pattern :IPCC Report (2007) • Precipitation has significantly increased (+) in eastern North and South America, northern and central Asia and northern Europe • There has been decline (-) in precipitation in the Mediterranean, some regions in southern Asia, southern Africa and Sahel Source: http://www.unep.org.

4. Global Glacier changes In 1999, a report by the Working Group on Himalayan Glaciology (WGHG) of the International Commission for Snow and Ice (ICSI) indicated that glaciers in the Himalayas are receding faster than in any other part of the world and may disappear by the year 2035 Dyurgerov and Meier (2005).

5. Glacier Changes in Himalaya Glaciers in Karakoram Mountain Range http://www.atmos.washington.edu/2009Q1/111/ATMS111%20Presentations/Folder%203/HughesS_BedionesJ.pdf Source: Hewitt, 2005

6. Glacier environment in the Karakoram Zone of maximum precipitation, 5,000-6,000 m asl, entirely within glacier accumulation zone --- and 2,500 m or more higher than in eastern Greater Himalaya of Nepal Source: Hewitt, 2005

7. Glacier and climate change in the Karakoram • The area come under the influence of two distinct weather systems: • Westerly circulation and cyclonic storms in winter- two-third of high altitude snow accumulation occurs in winter. • Summer monsoon- other one-third of snow fall occurs in summer. • Trends in temperature and precipitation since 1960 • Increase in winter precipitation. • Decrease in summer mean and minimum temperature- may be due to summer storms. • No increase in summer precipitation • Increase in winter temperature- less critical for high-altitude glaciers.

8. Glacier changes impact • Snow and glacier melt is the primary input to the discharge of many rivers • Billions of people living downstream depends on these water source • Short- and long-term effects on the hydrology of Himalaya rivers (flooding & drought) • Agriculture • Drinking water • Hydropower • Sea level

9. Problem statement • Few field studies; • The common type of glacier changes reported, is terminus retreat (from remotely sensed data); • Less significant than changes in ice thickness (debris-covered glaciers); • Lack of extensive weather data (remote rugged terrain);

10. Objectives • Quantify glacier mass balance of major glaciers in the Karakorum Himalaya Region using measurements of ice mass changes and areal extent of glaciated area from remotely sensed data; • Assess the effect of glacial fluctuations on annual discharge of major rivers; • Predict the impacts of future climate change on contribution from snow and glacier melt runoff to the total discharge of the rivers.

11. OBJECTIVE-1: QUANTIFICATION OF GLACIER CHANGES IN THE WESTERN KARAKORAM HIMALAYA REGION • Data sources • Landsat images (classification of glaciers into different zones) • Elevation data ( SRTM and ICESat) 16-8-2002 23-08-2002 16-7-2001 16-9-1999 16-8-2002 30-9-2001

12. Atmospheric correction • Correction applied to Digital Numbers of images to remove or reduce the influence of atmospheric conditions due to scattering and absorption by gases and aerosols particles. • The scattering mechanisms are: • 1) transmittance, 2) path irradiance, and 3) sky irradiance • Two types of methods: • 1) Relative • Image-based dark object subtraction (DOS) • Relative normalization • 2) Absolute • needs vertical distribution of water vapor, ozone content, aerosol content or visibility, horizontal Pixel values of low reflectance areas near zero such as deep shadows, or clear water are subtracted from image to correct for atmospheric path radiance.

13. Glacier Classification • Combination of Landsat bands 1-5, 7 and slope information from SRTM data were used in classification. • Maximum likelihood classification technique was used. • The images are classified into • Snow-covered ice • Clean ice • Debris covered areas • Water • Other terrain The assignment (‘classification’) of a pixel to a is made to particular class whose probability of occurrence at that point in spectral space is highest (‘most likely’)

14. Elevation data ( SRTM and ICESat) • The Ice, Cloud and Land Elevation Satellite (ICESat) launched in 2003 provides a globally-distributed elevation data set at 183-days repeat cycle. • Geoscience Laser Altimeter System (GLAS) utilizes laser pulses for measuring the heights of the surface with approax. 70 m resolution and at 170 m along-track spacing. • The Shuttle Radar Topography Mission(SRTM) product with 90 meter resolution was used as a reference DEM for computing elevation changes since February, 2000.

15. Elevation data ( SRTM and ICESat) • All available ICESat data over the glaciers from the spring acquisition campaigns were examined for the period of 2004-2008 • The elevation differences (ICESat - SRTM90) were computed for snow, ice and debris covered areas in eight sub-watersheds.

16. Accuracy of ICESat and SRTM • Errors related to steep slopes and rough topography for both ICESat and SRTM data • The surface changes estimation were only limited to areas with relatively low slopes. • noisy waveforms with many peaks are associated with steep slopes and rough topography • Radar penetration and sesonal snow difference: • Penetration of the radar signal into snow is another potential source of error.  No editing was done to account for SRTM snow penetration based on the assumption that the bias is relatively consistent for all the data points included in the analysis.

17. Preliminary results Data points on less than 10 degree slope All data points Snow- covered ice zone Clean ice zone

18. Preliminary results Snow- covered ice zone clean ice zone

19. Summary • Comparisons of elevation differences (ICESat - SRTM90) between years 2004-2008 shows an increase in elevation in the snow-covered ice zone (5000 - 6000m elevation). • In clean ice areas, there is a slight decrease in elevation relative to SRTM between 2004 and 2007, while the debris covered areas show no changes between 2004 and 2007. The statistical significance of these changes has not been assessed. • More positive elevation changes were seen on south east and south west facing slopes for snow covered areas than north facing slopes. A similar pattern is observed for ice covered areas where south and north western slopes show more positive changes. • This might be associated with two strong regional trends of precipitation in the Karakoram Himalaya i.e. the south and east facing slopes receive heavy precipitation due to monsoonal influence, while westerly winds give more precipitation to west and north facing slopes ( Young and Hewitt, 1990).

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21. OBJECTIVE-1:QUANTIFICATION OF GLACIER CHANGES IN THE WESTERN KARAKORAM HIMALAYA REGION Task-2: Estimation of changes in snow-covered glacier area using climate data from regional climate model and Landsat images. • Data sources: • Simulated climate data from regional climate model (estimate the boundary between accumulation and ablation zone using mass balance) • Total Solid Precipitation (each Year) – precipitation below zero degree celsius • Total melt – Degree-day method • Mass Balance = Total solid Precipitation (winter) – Total ice melt (summer) • Landsat images (Changes in snow-covered glacier area )

22. OBJECTIVE-2: ASSESS THE EFFECT OF GLACIAL FLUCTUATIONS ON ANNUAL DISCHARGE OF MAJOR RIVERS IN THE UIB (Nijssen et al, 2000), Adam et al, 2006, RegCM3 Climate Data VIC Model Objective-1 & Observed discharge data The Vegetation Continuous Fields (VCF) data from MODIS (500 m) Vegetation Point and Watershed Scale Model Calibration Soil properties ISRIC-WISE global dataset of derived soil properties & DEM derived Map Glacier extent Routing algorithm to simulate streamflow at watershed scale Objective-1

23. Prediction of long-term glaciers behaviour and their effects on streamflow variability by running the VIC model under future climate scenarios. OBJECTIVE-3: IMPACT OF FUTURE CLIMATE CHANGE ON WATER RESOURCES WITHIN UIB.

26. Waveform Analysis A waveform is digitally-recorded laser pulse which provides information on the elevation and distribution of distinct reflecting surfaces within the footprint. Adopted from Hoften et al., 2000