| 1. |
- Dammann, Dyre Oliver, 1985, et al.
(författare)
-
Applications of radar interferometry for measuring ice motion
- 2021
-
Ingår i: Proceedings of the International Conference on Port and Ocean Engineering under Arctic Conditions, POAC. - 0376-6756 .- 2077-7841. - 9781713841005 ; 2021-June
-
Konferensbidrag (refereegranskat)abstract
- Ongoing sea ice decline has major implications for human activities near sea ice due to shorter seasons for on-ice operations and thinner ice with reduced load-bearing capacity and stability in many regions. This may in turn lead to increased sea ice mobility and impacts of ice movement on structures. We investigate space-borne radar interferometry (InSAR) as a technique to measure mm-scale sea ice motion of stationary ice over weeks to months. We find that InSAR enables mapping of bottomfast and stabilized landfast ice as regions with near-zero or reduced deformation. We further use this data to derive landfast ice strain and stress enabling estimation of the fracturing potential along the Northstar Island ice road in the Beaufort Sea, Alaska. We further examine ground-based radar interferometry (GRI) as a tool to collect continuous near real-time measurements on the km-scale not possible with InSAR. Based on GRI measurements conducted in Utqiaġvik, Alaska, we demonstrate the ability to evaluate ice strain in stationary ice and track vertical ice displacement due to tides. We also collected GRI measurements at 500 Hz during a drifting ice camp in the Beaufort Sea. The high sampling rate enabled tracking of continuous strain and detection of subtle variations in behavior between ice regimes. Through this work, interferometry shows promise as a tool to observe ice motion at the relevant scales needed for assessing sea ice stability, identify precursors to failure events, and better understand the relationship between different ice properties and loads on structures.
|
|
| 2. |
- Dammann, Dyre Oliver, 1985, et al.
(författare)
-
Assessing sea ice trafficability in a changing arctic
- 2018
-
Ingår i: Arctic. - : The Arctic Institute of North America. - 1923-1245 .- 0004-0843. ; 71:1, s. 59-75
-
Tidskriftsartikel (refereegranskat)abstract
- Arctic sea ice has undergone rapid changes during the last few decades, with negative implications for over-ice travel and on-ice operations, which benefit from services provided by the sea ice. A Parameter-based Trafficability Hierarchy (PATH) is presented here as a framework for developing quantitative assessment strategies that can guide planning and execution of operations on or near sea ice and quantify the impacts of recent changes on ice use. A PATH assessment has been completed for three case studies in Arctic Alaska. These cases, which correspond to a range of different icescapes and ice uses, identify and quantify different parameters linked to trafficability and safe operations. For ice road applications, PATH was used to determine an ice thickness compensation factor, a factor increasing the minimal thickness threshold for operations, to help translate sporadic auger ice thickness measurements along the Kotzebue-Kiana community ice road into an envelope for safe operations. A compensation factor as high as 1.5 was found to be necessary to ensure safety because of the high local thickness variability that is currently a concern for ice road operators. A PATH assessment of ice roughness for ice trail routing at Utqiaġvik draws on satellite remote sensing and is relevant for over-ice travel in general, including escape, evacuation, and rescue. We compared the routing of local snowmobile trails with Synthetic Aperture Radar (SAR) data products to identify specific ranges of ice conditions, roughness, and topography favored for ice trail construction. The same combination of data sources was used to identify potentially beneficial trail routes. Finally, an ice stability and safety assessment was completed for ice road construction and maintenance by industry near the Northstar Island oil production facility. We evaluated small-scale ice displacement data obtained from SAR interferometry to infer internal ice strain and stress and used these data in assessing the potential for fractures to reduce load-bearing capacity.
|
|
| 3. |
- Dammann, Dyre Oliver, 1985, et al.
(författare)
-
Evaluating landfast sea ice stress and fracture in support of operations on sea ice using SAR interferometry
- 2018
-
Ingår i: Cold Regions Science and Technology. - : Elsevier BV. - 0165-232X. ; 149, s. 51-64
-
Tidskriftsartikel (refereegranskat)abstract
- Recent Arctic warming has led to reduced sea-ice thickness and a more dynamic landfast ice cover with potential widespread consequences for ice users. Here, we develop an approach to assess the small-scale deformation of landfast ice critical to on-ice operations using synthetic aperture radar interferometry (InSAR). InSAR has previously proven successful in determining long-term qualitative climatology of ice deformation around on-ice operations, but is now used to explore its potential for providing quantitative guidance for ice road planning, construction, and maintenance. A validation effort using X-band SAR and high-precision GPS data over Elson Lagoon, Alaska, confirms the ability of InSAR to accurately estimate 3-dimensional sea ice strain values accumulated between SAR image acquisitions, using an inverse model. The inverse model was further applied to L-band InSAR data over the Northstar Island ice road near Prudhoe Bay, Alaska. Assuming an elasto-brittle rheology, the derived strain values yielded a spatial distribution of internal stress consistent with preexisting ice defects and morphology. In several localized regions of the study area, stress values exceeded expected yield stress. Resulting relative fracture intensity potential was shown to conform with local knowledge based on road inspections by engineers, and may be used to guide ice road planning, construction and maintenance efforts. The results presented here demonstrate that InSAR is an accurate tool for estimating landfast ice deformation and stability in support of ice use. The findings may also provide substantial new insights into the mechanics of landfast ice.
|
|
| 4. |
- Dammann, Dyre Oliver, 1985, et al.
(författare)
-
Iceberg topography and volume classification using TanDEM-X interferometry
- 2019
-
Ingår i: Cryosphere. - : Copernicus GmbH. - 1994-0424 .- 1994-0416. ; 13:7, s. 1861-1875
-
Tidskriftsartikel (refereegranskat)abstract
- Icebergs in polar regions affect water salinity, alter marine habitats, and impose serious hazards on maritime operations and navigation. These impacts mainly depend on the iceberg volume, which remains an elusive parameter to measure. We investigate the capability of TanDEM-X bistatic single-pass synthetic aperture radar interferometry (InSAR) to derive iceberg subaerial morphology and infer total volume. We cross-verify InSAR results with Operation IceBridge (OIB) data acquired near Wordie Bay, Antarctica, as part of the OIB/TanDEM-X Antarctic Science Campaign (OTASC). While icebergs are typically classified according to size based on length or maximum height, we develop a new volumetric classification approach for applications where iceberg volume is relevant. For icebergs with heights exceeding 5 m, we find iceberg volumes derived from TanDEM-X and OIB data match within 7 %. We also derive a range of possible iceberg keel depths relevant to grounding and potential impacts on subsea installations. These results suggest that TanDEM-X could pave the way for future single-pass interferometric systems for scientific and operational iceberg mapping and classification based on iceberg volume and keel depth.
|
|
| 5. |
- Dammann, Dyre Oliver, 1985, et al.
(författare)
-
Instantaneous sea ice drift speed from TanDEM-X interferometry
- 2019
-
Ingår i: Cryosphere. - : Copernicus GmbH. - 1994-0424 .- 1994-0416. ; 13:4, s. 1395-1408
-
Tidskriftsartikel (refereegranskat)abstract
- The drift of sea ice is an important geophysical process with widespread implications for the ocean energy budget and ecosystems. Drifting sea ice can also threaten marine operations and present a hazard for ocean vessels and installations. Here, we evaluate single-pass along-track synthetic aperture radar (SAR) interferometry (S-ATI) as a tool to assess ice drift while discussing possible applications and inherent limitations. Initial validation shows that TanDEM-X phase-derived drift speed corresponds well with drift products from a ground-based radar at Utqiagvik, Alaska. Joint analysis of TanDEM-X and Sentinel-1 data covering the Fram Strait demonstrates that S-ATI can help quantify the opening/closing rate of leads with possible applications for navigation. S-ATI enables an instantaneous assessment of ice drift and dynamic processes that are otherwise difficult to observe. For instance, by evaluating sea ice drift through the Vilkitsky Strait, Russia, we identified short-lived transient convergence patterns. We conclude that S-ATI enables the identification and analysis of potentially important dynamic processes (e.g., drift, rafting, and ridging). However, current limitations of S-ATI are significant (e.g., data availability and they presently only provide the cross-track vector component of the ice drift field) but may be significantly reduced with future SAR systems.
|
|
| 6. |
- 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.
|
|
| 7. |
- Dammann, Dyre Oliver, 1985, et al.
(författare)
-
Mapping pan-Arctic landfast sea ice stability using Sentinel-1 interferometry
- 2019
-
Ingår i: Cryosphere. - : Copernicus GmbH. - 1994-0424 .- 1994-0416. ; 13:2, s. 557-577
-
Tidskriftsartikel (refereegranskat)abstract
- Arctic landfast sea ice has undergone substantial changes in recent decades, affecting ice stability and including potential impacts on ice travel by coastal populations and on industry ice roads. We present a novel approach for evaluating landfast sea ice stability on a pan-Arctic scale using Synthetic Aperture Radar Interferometry (InSAR). Using Sentinel-1 images from spring 2017, we discriminate between bottomfast, stabilized, and nonstabilized landfast ice over the main marginal seas of the Arctic Ocean (Beaufort, Chukchi, East Siberian, Laptev, and Kara seas). This approach draws on the evaluation of relative changes in interferometric fringe patterns. This first comprehensive assessment of Arctic bottomfast sea ice extent has revealed that most of the bottomfast sea ice is situated around river mouths and coastal shallows. The Laptev and East Siberian seas dominate the aerial extent, covering roughly 4100 and 5100 km(2), respectively. These seas also contain the largest extent of stabilized and nonstabilized landfast ice, but are subject to the largest uncertainties surrounding the mapping scheme. Even so, we demonstrate the potential for using InSAR for assessing the stability of landfast ice in several key regions around the Arctic, providing a new understanding of how stability may vary between regions. InSAR-derived stability may serve for strategic planning and tactical decision support for different uses of coastal ice. In a case study of the Nares Strait, we demonstrate that interferograms may reveal early-warning signals for the breakup of stationary sea ice.
|
|
| 8. |
- Dammann, Dyre Oliver, 1985, et al.
(författare)
-
New possibilities using TSX and TDX in support of sea ice use
- 2018
-
Ingår i: Proceedings of the European Conference on Synthetic Aperture Radar, EUSAR. - 2197-4403. ; 2018-June, s. 159-164
-
Konferensbidrag (refereegranskat)abstract
- Sea ice travel and on-ice operations are important for Arctic coastal communities and industrial operations. Recent rapid changes in Arctic sea ice impacting ice users emphasize the need for assessment strategies capable of guiding decision makers and documenting change in key ice-use related parameters. In this paper, we demonstrate the potential for the use of TSX and TDX interferometry to assess deformation, drift, and roughness of coastal sea ice. Through on-ice validation using Structure-from-Motion and high-precision GPS, we demonstrate a high level of detail and accuracy potentially enabling the use of these products in decision making.
|
|
| 9. |
- 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.
|
|
| 10. |
- Marbouti, Marjan, et al.
(författare)
-
Evaluating landfast sea ice ridging near UtqiagVik Alaska Using TanDEM-X interferometry
- 2020
-
Ingår i: Remote Sensing. - : MDPI AG. - 2072-4292. ; 12:8
-
Tidskriftsartikel (refereegranskat)abstract
- Seasonal landfast sea ice stretches along most Arctic coastlines and serves as a platform for community travel and subsistence, industry operations, and as a habitat for marine mammals. Landfast ice can feature smooth ice and areas of m-scale roughness in the form of pressure ridges. Such ridges can significantly hamper trafficability, but if grounded can also serve to stabilize the shoreward ice. We investigate the use of synthetic aperture radar interferometry (InSAR) to assess the formation and movement of ridges in the landfast sea ice near Utqiagvik, Alaska. The evaluation is based on the InSAR-derived surface elevation change between two TanDEM-X bistatic image pairs acquired during January 2012. We compare the results with backscatter intensity, coastal radar data, and SAR-derived ice drift and evaluate the utility of this approach and its relevance for evaluation of ridge properties, as well as landfast sea ice evolution, dynamics, and stability. © 2020 by the authors.
|
|
