Estimating statistical errors in retrievals of ice velocity and deformation parameters from satellite images and buoy arrays
<p>The objective of this note is to provide the background and basic tools to estimate the statistical error of deformation parameters that are calculated from displacement fields retrieved from synthetic aperture radar (SAR) imagery or from location changes of position sensors in an array. We...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2020-09-01
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| Series: | The Cryosphere |
| Online Access: | https://tc.copernicus.org/articles/14/2999/2020/tc-14-2999-2020.pdf |
| Summary: | <p>The objective of this note is to provide the background
and basic tools to estimate the statistical error of deformation parameters
that are calculated from displacement fields retrieved from synthetic
aperture radar (SAR) imagery or from location changes of position sensors in
an array. We focus here specifically on sea ice drift and deformation. In
the most general case, the uncertainties of divergence/convergence, shear,
vorticity, and total deformation are dependent on errors in coordinate
measurements, the size of the area and the time interval over which these
parameters are determined, as well as the velocity gradients within the boundary of
the area. If displacements are calculated from sequences of SAR images, a
tracking error also has to be considered. Timing errors in position readings
are usually very small and can be neglected. We give examples for magnitudes
of position and timing errors typical for buoys and SAR sensors, in the
latter case supplemented by magnitudes of the tracking error, and apply the
derived equations on geometric shapes frequently used for deriving
deformation from SAR images and buoy arrays. Our case studies show that the
size of the area and the time interval for calculating deformation
parameters have to be chosen within certain limits to make sure that the
uncertainties are smaller than the magnitude of deformation parameters.</p> |
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| ISSN: | 1994-0416 1994-0424 |