5_Glacier_IGARSS11_Eineder.ppt

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  • Show position, size History, Larsen A ice shelf break up in Jan 1995 Speedup from 2-3 m/s to 6 m/s in 1995 Why Drygalski Glacier? Have new X-Band TerraSAR-X in 2007 Research, what can be done Fast flowing glacier, accelerated since 1995 What? Show what can be done w.r.t. Velocity tracking 3D Surface mapping Accuracy analysis
  • Schwimmt in unteren 10 km vermutlich auf
  • Einsinken bis zu 10 cm / Tag + Tidenhub!!
  • B <
  • Massiv außer Balance seit 1995. Starkes Ausdünnen durch Massendivergenz.
  • 5_Glacier_IGARSS11_Eineder.ppt

    1. 1. GLACIER FLOW AND TOPOGRAPHY MEASUREMENTS WITH TERRASAR-X AND TANDEM-X M. Eineder 1 ) , W. Abdel Jaber 2) , D. Floricioiu 1) , H. Rott 3) , N. Yague-Martinez 1) 1) German Aerospace Center, 2) Technische Universität München, 3) Universität Innsbruck IGARSS 2011
    2. 2. Drygalski Glacier, Antarctica From: Rott et al. EUSAR 2008
    3. 3. Drygalski Glacier after Collapse of Larsen A Photo: H. Rott
    4. 4. TerraSAR-X and TanDEM-X Observations Preliminary TanDEM-X DEMs TS-X 11 day intervall series TS-X 3 repetitions 11 day intervall Stripmap mode, nominal resolution < 3 m
    5. 5. Video of 2007-2008 Time Series (30 Frames) <ul><li>Maybe zooms to different interesting spots </li></ul>
    6. 6. Velocity Analysis Method <ul><li>11 day intervalls </li></ul><ul><li>Incoherent (amplitude) image correlation technique </li></ul><ul><ul><li>Use of geocoded standard products, 1.25 m spacing, 1.3 looks </li></ul></ul><ul><ul><li>2D shift measurement </li></ul></ul><ul><ul><li>Absolute displacement  no tie-points, no phase ambiguity </li></ul></ul><ul><ul><li>Chip size 256 2 pixels (320m) 2 </li></ul></ul>Speckle Feature
    7. 7. Velocity Estimation – Systematic Errors (Bias) <ul><li>Orbit error </li></ul><ul><li>Timing error </li></ul><ul><li>Atmosphere </li></ul><ul><li>Solid Earth tides </li></ul>See Eineder et al., Imaging Geodesy—Toward Centimeter-Level Ranging Accuracy With TerraSAR-X, IEEE TGRS 2010
    8. 8. Velocity Estimation – Random Errors <ul><li>Feature correlation: </li></ul><ul><li>DEM error: </li></ul><ul><li>Total = random + systematic error: </li></ul>
    9. 9. Average Three-Year Velocity Map 0.0 6.0 [m/d] 5 km A C
    10. 10. Temporal Velocity Profile at Point A (Terminus) Linear fit 2007-2010: -0.166 md -1 a -1 Linear fit 2007/2008: -0.336 md -1 a -1 Summer Winter Summer Winter Summer Winter  Significant seasonal variations and decelleration
    11. 11. Temporal Velocity Profile at Point C Summer Winter Summer Winter Summer Winter  Measurements confirm error margin (residuals stdev. < 2 cm d -1 )  slight seasonal variations, maybe decelleration
    12. 12. One-Year Deceleration Map A C -0.4 0.4 [md -1 a -1 ]
    13. 13. Three-Year Deceleration Map A C -0.4 0.4 [md -1 a -1 ]
    14. 14. Average Spatial Correlation Coefficient 0.0 0.7
    15. 15. Two Preliminary TanDEM-X DEMs Available <ul><li>Descending </li></ul><ul><ul><li>2010-10-21 </li></ul></ul><ul><ul><li>Beff=180.2 m </li></ul></ul><ul><ul><li>H/2PI=-46.08 m </li></ul></ul><ul><li>Ascending </li></ul><ul><ul><li>2010-12-11 </li></ul></ul><ul><ul><li>Beff=26.0 m </li></ul></ul><ul><ul><li>H/2PI=-323.2 </li></ul></ul><ul><li> Used both DEMs for height offset determination </li></ul><ul><li> Used descending DEM for analysis </li></ul>
    16. 16. Shaded DEM and 20 m Contour Lines Terminus
    17. 17. Drygalski Glacier Terminus Height Profile (Small Baseline DEM) 70 m  ~460 m
    18. 18. Difference TanDEM-X (asc) – GLOBE DEM 300 m -300 m 0 m  1. Height loss (?), 2. Velocity and geocoding errors
    19. 19. TanDEM-X DEM Roughness Map <ul><li>Roughnes map </li></ul>0.0 3.0 σ h [m] Roughness based on 10 x 10 pixel plane residuals (50 x 50 m 2 )  Coincides with correlation map, confirms DEM quality
    20. 20. Conclusions <ul><li>Demonstrated multi-year feature tracking on glacier with 3 cmd -1 accuracy over larger areas </li></ul><ul><li>Acceleration since 1995 confirmed again </li></ul><ul><li>Detected strong seasonal variations ( ±0.4 md -1 ) at terminus </li></ul><ul><li>Hints for slight (-0.166 md -1 a -1 ) deceleration 2007-2010 at terminus </li></ul><ul><li>TanDEM-X DEM height errors within expectations over glacier </li></ul><ul><li>TanDEM-X DEM roughness predicts feature correlation quality </li></ul><ul><li>TanDEM-X DEM useful for terminus height / thickness estimation </li></ul>

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