| 1. |
- Dammann, Dyre Oliver, 1985, et al.
(författare)
-
Mapping Arctic Bottomfast Sea Ice Using SAR Interferometry
- 2018
-
Ingår i: Remote Sensing. - : MDPI AG. - 2072-4292. ; 10:5
-
Tidskriftsartikel (refereegranskat)abstract
- Bottomfast sea ice is an integral part of many near-coastal Arctic ecosystems with implications for subsea permafrost, coastal stability and morphology. Bottomfast sea ice is also of great relevance to over-ice travel by coastal communities, industrial ice roads, and marine habitats. There are currently large uncertainties around where and how much bottomfast ice is present in the Arctic due to the lack of effective approaches for detecting bottomfast sea ice on large spatial scales. Here, we suggest a robust method capable of detecting bottomfast sea ice using spaceborne synthetic aperture radar interferometry. This approach is used to discriminate between slowly deforming floating ice and completely stationary bottomfast ice based on the interferometric phase. We validate the approach over freshwater ice in the Mackenzie Delta, Canada, and over sea ice in the Colville Delta and Elson Lagoon, Alaska. For these areas, bottomfast ice, as interpreted from the interferometric phase, shows high correlation with local bathymetry and in-situ ice auger and ground penetrating radar measurements. The technique is further used to track the seasonal evolution of bottomfast ice in the Kasegaluk Lagoon, Alaska, by identifying freeze-up progression and areas of liquid water throughout winter.
|
|
| 2. |
- Dammann, Dyre Oliver, 1985, et al.
(författare)
-
Traversing Sea Ice-Linking Surface Roughness and Ice Trafficability Through SAR Polarimetry and Interferometry
- 2018
-
Ingår i: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing. - 2151-1535 .- 1939-1404. ; 11:2, s. 416-433
-
Tidskriftsartikel (refereegranskat)abstract
- Arctic landfast sea ice is widely utilized for transportation by local communities and industry, with trafficability largely governed by ice roughness. Here, we introduce an approach to evaluate ice roughness that can aid in routing of ice roads and assessment of spatial variability and long-term changes in trafficability. Drawing on synthetic aperture radar (SAR) polarimetry, SAR interferometry (InSAR), and other remote sensing techniques, we integrated approaches into the trafficability assessment that had rarely been applied over sea ice in the past. Analysis of aerial photogrammetry obtained through structure-from-motion helped verify cm-scale accuracy of X-band InSAR-derived ridge height and link L-band polarimetric classification to specific roughness regimes. Jointly, these approaches enable a km-scale evaluation of ridge topography and cm-to m-scale roughness-both critical for the assessment of trafficability. A trafficability index was derived from such SAR data in conjunction with analysis of ice trail routing and ice use near Utqiaġvik, Alaska. The index identifies areas of reduced trafficability, associated with pressure ridges or rubble ice, and served to delineate favorable trail routes for different modes of transportation, with potential uses ranging from ice road routing to emergency evacuation. Community outreach is needed to explore how this approach could assist different ice users in reducing risk, minimizing trail or ice construction efforts, and improving safety.
|
|
| 3. |
- Mahoney, Craig, et al.
(författare)
-
Slope Estimation from ICESat/GLAS
- 2014
-
Ingår i: Remote Sensing. - : MDPI AG. - 2072-4292. ; 6:10, s. 10051-10069
-
Tidskriftsartikel (refereegranskat)abstract
- We present a novel technique to infer ground slope angle from waveform LiDAR, known as the independent slope method (ISM). The technique is applied to large footprint waveforms (similar to 60 m mean diameter) from the Ice, Cloud and Land Elevation Satellite (ICESat) Geoscience Laser Altimeter System (GLAS) to produce a slope dataset of near-global coverage at 0.5 degrees x 0.5 degrees resolution. ISM slope estimates are compared against high resolution airborne LiDAR slope measurements for nine sites across three continents. ISM slope estimates compare better with the aircraft data (R-2 = 0.87 and RMSE = 5.16 degrees) than the Shuttle Radar Topography Mission Digital Elevation Model (SRTM DEM) inferred slopes (R-2 = 0.71 and RMSE = 8.69 degrees). ISM slope estimates are concurrent with GLAS waveforms and can be used to correct biophysical parameters, such as tree height and biomass. They can also be fused with other DEMs, such as SRTM, to improve slope estimates.
|
|
