scholarly journals The Glacier and Land Ice Surface Topography Interferometer: An Airborne Proof-of-Concept Demonstration of High-Precision Ka-Band Single-Pass Elevation Mapping

2011 ◽  
Vol 49 (2) ◽  
pp. 827-842 ◽  
Author(s):  
Delwyn Moller ◽  
Scott Hensley ◽  
Gregory A. Sadowy ◽  
Charles D. Fisher ◽  
Thierry Michel ◽  
...  
2017 ◽  
Author(s):  
Wolfgang Dierking ◽  
Oliver Lang ◽  
Thomas Busche

Abstract. Quantitative parameters characterizing the sea ice surface topography are needed in geophysical investigations such as studies on atmosphere-ice interactions or sea ice mechanics. Recently, the use of space-borne single-pass interferometric synthetic aperture radar (InSAR) for retrieving the ice surface topography has attracted notice among geophysicists. In this paper the potential of InSAR measurements is examined for several satellite configurations and radar frequencies, considering statistics of heights and widths of ice ridges as well as possible magnitudes of ice drift. It is shown that theoretically surface height variations can be retrieved with relative errors ≤ 0.5 m. In practice, however, the sea ice drift and open water leads may contribute significantly to the measured interferometric phase. Another essential factor is the dependence of the achievable interferometric baseline on the satellite orbit configurations. Possibilities to assess the influence of different factors on the measurement accuracy are demonstrated: signal-to-noise ratio, presence of a snow layer, and the penetration depth into the ice. Practical examples of sea surface height retrievals from bistatic SAR images collected during the TanDEM-X Science Phase are presented.


2017 ◽  
Vol 11 (4) ◽  
pp. 1967-1985 ◽  
Author(s):  
Wolfgang Dierking ◽  
Oliver Lang ◽  
Thomas Busche

Abstract. Quantitative parameters characterizing the sea ice surface topography are needed in geophysical investigations such as studies on atmosphere–ice interactions or sea ice mechanics. Recently, the use of space-borne single-pass interferometric synthetic aperture radar (InSAR) for retrieving the ice surface topography has attracted notice among geophysicists. In this paper the potential of InSAR measurements is examined for several satellite configurations and radar frequencies, considering statistics of heights and widths of ice ridges as well as possible magnitudes of ice drift. It is shown that, theoretically, surface height variations can be retrieved with relative errors  ≤  0.5 m. In practice, however, the sea ice drift and open water leads may contribute significantly to the measured interferometric phase. Another essential factor is the dependence of the achievable interferometric baseline on the satellite orbit configurations. Possibilities to assess the influence of different factors on the measurement accuracy are demonstrated: signal-to-noise ratio, presence of a snow layer, and the penetration depth into the ice. Practical examples of sea surface height retrievals from bistatic SAR images collected during the TanDEM-X Science Phase are presented.


2020 ◽  
Author(s):  
Sinéad Farrell ◽  
Kyle Duncan ◽  
Ellen Buckley ◽  
Jacqueline Richter-Menge ◽  
Ruohan Li

2018 ◽  
Author(s):  
Alexey Anatolievich Morozov

Colijn-Plazotta tree shape labeling scheme allows to describe an arbitrary phylogenetic tree topology by recursively labeling all nodes from tips to root with integers. The multisets of these labels can then be used to estimate the difference between topologies using eg Euclidean distance. In this work I propose an extension of the labeling scheme (and thus a distance metric) to unrooted trees, which is achieved by labeling all rooted subtrees within a given tree. To avoid exhaustively enumerating the subtrees, the labels are collected into a dependency graph and calculated in a single pass. A proof-of-concept implementation is available at https://github.com/synedraacus/metrics.


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