Urs Wegmüller, Maurizio Santoro, Charles Werner, Tazio Strozzi and Andreas Wiesmann Gamma Remote Sensing, Gümligen, Switzerland ESTIMATION OF ICE THICKNESS OF TUNDRA LAKES USING ERS – ENVISAT CROSS- INTERFEROMETRY This work was supported by ESA under contract 22526/09/I-LG. ERS and ASAR data copyright ESA (CAT 6744).
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TU1.L10.2 - ESTIMATION OF ICE THICKNESS OF TUNDRA LAKES USING ERS–ENVISAT CROSS-INTERFEROMETRY
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Urs Wegmüller, Maurizio Santoro, Charles Werner,Tazio Strozzi and Andreas Wiesmann
Gamma Remote Sensing, Gümligen, Switzerland
ESTIMATION OF ICE THICKNESS OF TUNDRA LAKES USING ERS – ENVISAT CROSS-
INTERFEROMETRY
This work was supported by ESA under contract 22526/09/I-LG.ERS and ASAR data copyright ESA (CAT 6744).
Motivation
ERS – ENVISAT Cross-Interferometry (EET-CInSAR)
Ice thickness estimation methodology
Results over Kolyma area, Siberia
Results over Mackenzie area, Canada Conclusions
Outline
Significant interest in information on Tundra lakes and frozen rivers
Freezing of tundra lakes and rives relevant for several applications reaching from ice road planningto environmental consideration and climate change
One important parameter is the ice-thickness
Space-borne SAR has shown significant potential already over tundra areas
ERS – ENVISAT Cross-Interferometry (EET-CInSAR) data available over tundra areas
Coherence over frozen lakes is usually high and phase looks different from surrounding, indicating some potential to derive information
Motivation
EET Cross-Interferogram over Kolyma River Delta area(20-Jan-2009, dt= 28min., B⊥= 2130m, dDC= 139Hz)
Mackenzie River (10-Mar-2009, B⊥=2247m, dDC=344Hz)
ENVISAT backscattering Cross-interferogram phase
Mackenzie River (10-Mar-2009, B⊥=2247m, dDC=344Hz)
ENVISAT backscattering
ection 1, incl. points measured in 27.2-9.3.2009 by J.J. van Sanden et al. 2009
Mackenzie River (10-Mar-2009, B⊥=2247m, dDC=344Hz)
Cross-interferogram phase
ection 1, incl. points measured in 27.2-9.3.2009 by J.J. van Sanden et al. 2009
+3A
+3C
+3B
+ + *
+
* h=0 ref. used
Mackenzie River (10-Mar-2009, B⊥=2247m, dDC=344Hz)
ffective height transect (negative values correspond to ice thickness)
: value from J.J. van Sanden et al., 2009
* h=0 ref. used
*
Mackenzie River (10-Mar-2009, B⊥=2247m, dDC=344Hz)
ENVISAT backscattering
ection 2, incl. points measured in 27.2-9.3.2009 by J.J. van Sanden et al. 2009
Mackenzie River (10-Mar-2009, B⊥=2247m, dDC=344Hz)
Cross-interferogram phase
ection 2, incl. points measured in 27.2-9.3.2009 by J.J. van Sanden et al. 2009
+8A
+8B
+
+ *
* h=0 ref. used
Mackenzie River (10-Mar-2009, B⊥=2247m, dDC=344Hz)
ffective height transect (negative values correspond to ice thickness)
: value from J.J. van Sanden et al., 2009
* h=0 ref. used
*
Conclusions
EET pairs with 2km and 28’ time interval coherence often high over frozen lakes high sensitivity of CINSAR to ice thickness (hamb,ice ≅ 3m)
From unwrapped CINSAR phases relative to a point on the coast representing the lake(-ice) surface level, ice thickness maps can be derived (for highly transparent fresh-water ice)
In the case of bottom-fast ice (i.e. ice frozen to the ground) this corresponds to the mapping of the lake floor topography
For frazil ice (snow/water mixture) and for ice covered by wet snow or water, and for sea ice the dominant scattering is not from the ice/water or ice/lake ground interface, so that the presented methodology is not applicable
The comparison with a few in-situ measured ice thickness values confirmed the potential
Outlook
In 2007/08 and 2008/09 suitable EET pairs were acquired over quite many northern sites, so that the presented methodology may be applied elsewhere
Acquiring further EET pairs after Oct. 2010 is not foreseen