Snow and Glacier Changes in the Upper Indus Basin

Transcription

1 Snow and Glacier Changes in the Upper Indus Basin Tobias Bolch Department of Geography, Universität Zürich, Switzerland Funding: DFID (ICIMOD-Indus), ESA (Glaciers_cci), T. Bolch et al. 1/36 Indus Basin and Subbasins T. Bolch et al. 2/36 1

2 Length Changes of Glaciers in Himalaya Karakoram Bolch et al. (2012) Hewitt (2011) T. Bolch et al. 3/36 Length Changes of Glaciers in Karakoram T. Bolch et al. 4/36 2

3 Length Changes of Glaciers in Karakoram 1969 Corona Image Glaciers_cci 2014 T. Bolch et al. 5/36 Arun Co Ice Avalanche Thanks to F. Paul T. Bolch et al. 6/36 3

4 Arun Co Ice Avalanche T. Bolch et al. 7/36 Arun Co Ice Avalanche Thanks to A. Kääb, Oslo T. Bolch et al. 8/36 4

5 Arun Co Ice Avalanche Thanks to T. Lide, T. Yao ITP T. Bolch et al. 9/36 Area Changes of Glaciers in Karakoram Area Changes in Central Karakoram Minora et al. (2016), PPG Area Changes in Upper Shyok Valley (NE Karakoram) Bhambri et al. (2013), TC T. Bolch et al. 10/36 5

6 Mass Balance Data of Himalaya Himalaya: Available mass balance data until Spring 2012 Bolch et al. (2012), Science T. Bolch et al. 11/36 Geod. Mass Balance Data of High Asia Elevation difference using ICESat Data Kääb et al. 2015, TC T. Bolch et al. 12/36 6

7 Geod. Mass Balance Data of High Asia Mass Balance using ICESat Data Neckel, Kropacek, Bolch, Hochschild (2014), Environ Res. Lett. T. Bolch et al. 13/36 Geod. Mass Balance Data of Karakoram Karakoram /10 based on SPOT and SRTM data ± 0.18 m w.e. a ± 0.14 m w.e. a -1 Gardelle et al. 2013, TC T. Bolch et al. 14/36 Gardelle et al. 2013, TCD 7

8 Study Region Altay Northern Tien Shan Northern Pamir Central Tien Shan Hunza Valley/ Karakoram Langtang Himal Central Tibetan Plateau Khumbu Himal Sikkim Himalaya T. Bolch et al. 15/36 Study Region Hunza Valley Glacierized area ~ 3600 km² Batura Gl. Khurdopin Gl. Hispar Gl. Run-off station T. Bolch et al. 16/36 8

9 RS Data for DEM Generation Data Time Res. Data/ DEM (m) Footprint/Coverage Air Photos Corona KH-4, KH-4A/B Since ~ s 1970s < 1 - > 5 / ~ 5 20 Small 2-8 / ~20 x 180 km Hexagon KH9 1970s 4-12 / x 240 km KFA-1000/MK /90s 2-15 /10-40 SRTM1/SRTM3 Feb /90 global ASTER since / x 60 km Cartosat -1, ALOS, SPOT 5 TanDEM-X, Plejades etc. since / x x 60 km since ~2010 from 0.5 m / < 10 T. Bolch et al. 17/36 Method: DEM differencing But DEM differencing is not straight forward Original DEMs, e.g. Cartosat KH4B -> Tilt, Shift, Voids -> Careful co-registration necessary -> Further challenges: Volume to mass conversion Radar penetration Bolch et al. 2008, J. Glac. Pieczonka et al. 2011, ISPRS Nuth and Kääb 2011, TC Gardelle et al. 2012, J. Glac. Huss 2013, TC Pieczonka & Bolch 2015, GPC T. Bolch et al. 18/36 9

10 AST14DMO ( ) SRTM1 (~1999) Merge of 10 ASTER DEMs SRTM1 (30 m res.) Geod. Mass Balance Hunza Valley Mean elevation change: +1.7 m Radar Penetration ~ 2.4 m Density 850 kg m -3 Batura Gl.: ± 0.26 m w.e. a -1 Mass Budget: All glaciers: ± 0.21 m w.e. a -1 Non-surge type: ± 0.20 m w.e. a -1 Surge type: ± 0.30 m w.e. a -1 Khurdopin Gl.: ± 0.22 m w.e. a -1 Hispar Gl.: ± 0.22 m w.e. a -1 Bolch et al. (2016) T. Bolch et al. 19/36 Geod. Mass Balance Hunza Valley T. Bolch et al. 20/36 10

11 Geod. Mass Balance Hunza Valley Cartosat-1 (2010) SRTM1 (~1999) Khurdopin Glacier: ASTER-SRTM: ± 0.21 m w.e. a -1 CARTO-SRTM: ± 0.13 m w.e. a -1 T. Bolch et al. 21/36 SRTM1 (~1999) Hexagon KH9 (1974) Merge of 2 KH9 DEMs Geod. Mass Balance Hunza Valley Mean elevation change: -2.3 m Radar Penetration 2.4 m Density 850 kg m -3 Batura Gl.: ±0.10 m w.e. a -1 Mass Budget: All glaciers: ± 0.09 m w.e. a -1 Non-surge type: ± 0.08 m w.e. a -1 Surge type: ± 0.10 m w.e. a -1 Khurdopin Gl.: ± 0.09 m w.e. a -1 Hispar Gl.: ± 0.08 m w.e. a -1 Bolch et al. (2016) T. Bolch et al. 22/36 11

12 Longitudinal profiles of surface elevation changes for selected glaciers for the two periods T. Bolch et al. 23/36 Geod. Mass Balance Siachen Glacier Mass Changes of Siachen Glacier (2007 Cartosat-1 DEM vs. 1999/2000 SRTM DEM) -0.03± 0.21 m w.e. a -1 Agarwal, Bolch et al. (in rev.), J. Glac. T. Bolch et al. 24/36 12

13 Siachen Glacier Area changes Agarwal, Bolch et al. (in rev.), J. Glac. T. Bolch et al. 25/36 Snow cover: MODIS coverage Gafurov et al. (2012) T. Bolch et al. 26/36 13

14 Snow cover: Cloud filling Data: NSIDC Snow Products from MODIS Terra and Aqua Cloud Cover Cloud removal: 1. Combine Terra and Aqua images from the same day 2. Temporal Filtering: Use pixel from day before/after 3. Spatial Filtering: Replace pixel with dominant class of neighbouring pixels Snow Cover Hasson et al. (2014) T. Bolch et al. 27/36 Snow cover Mean daily snow cover and its variability over the period for the different subbasins. Hasson et al. (2014) T. Bolch et al. 28/36 14

15 Snow cover variability Annual snow coverage Seasonal trends in snow coverage Hasson et al. (2014) T. Bolch et al. 29/36 Late Summer Snow Line Median elevation of glaciers and inter-annual variability of the end-of-summer regional SLA zone Hasson et al. (2014) T. Bolch et al. 30/36 15

16 21/12/2016 Glacier Change Langtang Valley Surface Velocity Surface Elevation Change Ragettli, Bolch, Pellicciotti (2016), TC T. Bolch et al. 31/36 Suitable data for Geod. Mass Balance Pleiades Cartosat-1/2 T. Bolch et al. 32/36 16

17 Ice-debris Complexes Occurrence of ice-debris complexes Corona KH4 Hexagon KH9 Pléiades T. Bolch et al. 33/36 Ice-debris Complexes T. Bolch et al. 34/36 17

18 Exiting and New Glacier Measurements Status 2012 Many new measurements were established during the recent years Bolch et al. 2012, Science T. Bolch et al. 35/36 Conclusions Declassified KH-9 Hexagon data are suitable to assess glacier elevation changes since the 1970s. We show that glaciers in Hunza valley are in balance at least since the 1970s. Hence, no additional run-off due to glacier mass loss as it is the case in many other Himalayan catchments. However, our study area covers only parts of the Upper Indus Basin and uncertainties are significant. Extended in-situ and geodetic measurements as well as modelling are needed to fully understand the past and predict the future of the glaciers. Emphasis need to be given to surge-type glaciers. Recent high resolution stereo data is very promising for geodetic mass balance assessments. T. Bolch et al. 36/36 18

19 Thank you very much for your attention! T. Bolch et al. 37/36 Geod. Mass Balance Hunza Valley T. Bolch et al. 38/36 19