Incorporation of Flow Stripes as Constraints for Calibrating Ice Surface Velocity Measurements from Interferometric SAR Data

2008 ◽  
Vol 74 (12) ◽  
pp. 1501-1508 ◽  
Author(s):  
Hongxing Liu ◽  
Jaehyung Yu ◽  
Zhiyuan Zhao ◽  
Kenneth C. Jezek
2012 ◽  
Vol 6 (3) ◽  
pp. 2005-2036 ◽  
Author(s):  
S. H. Mernild ◽  
N. T. Knudsen ◽  
J. C. Yde ◽  
M. J. Hoffman ◽  
W. H. Lipscomb ◽  
...  

Abstract. Glaciers in Southeast Greenland have thinned and receded during the past several decades. Here, we document changes for the Mittivakkat Gletscher, the only glacier in Greenland with long-term mass balance observations and surface velocity measurements (since 1995). Between 1986 and 2011, this glacier shrank by 18 % in surface area, 20 % in mean ice thickness, and 33 % in volume. We attribute these changes to summertime warming and to drier winter conditions. Meanwhile, the annual mean ice surface velocity decreased by 30 %, likely as a dynamic result of thinning. This dynamic thinning is predicted by ice deformation theory but has rarely been observed on decadal time scales. Mittivakkat Gletscher summer surface velocities were on average 50–60 % above winter background values, and up to 160 % higher during peak velocity events. The transition from winter to summer values followed the onset of positive temperatures. Satellite observations show area losses for most other glaciers in the region; these glaciers are likely also to have lost volume (in average around one-third) and slowed down in recent decades.


2014 ◽  
Vol 26 (6) ◽  
pp. 661-673 ◽  
Author(s):  
Neil F. Glasser ◽  
Tom Holt ◽  
Ed Fleming ◽  
Carl Stevenson

AbstractThis paper presents InSAR-derived ice shelf velocities and observations of surface debris deformation on the McMurdo Ice Shelf (MIS). Ice shelf velocities show that the MIS has a low surface velocity, with debris-laden parts of the ice shelf in the area known as the ‘swirls’ averaging speeds of c. 3 m a-1 increasing to c. 16 m a-1 at the ice front. Analysis of the fold patterns within moraine ridges on the ice surface reveals a deformational history inconsistent with the present velocity measurements. Polyphase, isoclinal folding within moraine ridges at the surface are interpreted to have formed through intense deformation by past ice flow in a NNW orientation. The velocities and styles of deformation indicate that the majority of debris on the ice shelf was originally transported into the area by a large and dynamic ice sheet/ice shelf system entirely different to that of the present configuration. Although the age of this event is unknown, it is possible that this debris has been exposed on the surface of the ice shelf since the last glacial maximum.


2002 ◽  
Vol 23 (3) ◽  
pp. 461-475 ◽  
Author(s):  
Olaf Hellwich ◽  
Ivan Laptev ◽  
Helmut Mayer
Keyword(s):  
Sar Data ◽  

2021 ◽  
Author(s):  
Joseph H. Kennedy ◽  
Krik Hogenson ◽  
Andrew Johnston ◽  
Heidi Kristenson ◽  
Alex Lewandowski ◽  
...  

<p>Synthetic Aperture Radar (SAR), with its capability of imaging day or night, ability to penetrate dense cloud cover, and suitability for interferometry, is a robust dataset for event/change monitoring. SAR data can be used to inform decision makers dealing with natural and anthropogenic hazards such as floods, earthquakes, deforestation and glacier movement. However, SAR data has only recently become freely available with global coverage, and requires complex processing with specialized software to generate analysis-ready datasets. Furthermore, processing SAR is often resource-intensive, in terms of computing power and memory, and the sheer volume of data available for processing can be overwhelming. For example, ESA's Sentinel-1 has produced ~10PB of data since launch in 2014. Even subsetting the data to a small scientific area of interest can result in many thousands of scenes, which must be processed into an analysis-ready format.</p><p>The Alaska Satellite Facility (ASF) Hybrid Pluggable Processing Pipeline (HyP3), which is now out of beta and available to the public, provides custom, on-demand processing of Sentinel-1 SAR data at no cost to users. HyP3 is integrated directly into Vertex, ASF's primary data discovery tool, so users can easily select an area of interest on the Earth, find available SAR products, and click a button to send them (individually, or as a batch) to HyP3 for Radiometric Terrain Correction (RTC), Interferometric SAR (InSAR), or Change Detection processing. Processing leverages AWS cloud computing and is done in parallel for rapid product generation. Each process provides options to customize the processing and final output products, and provides metadata-rich, analysis-ready final products to users.</p><p>In addition to the Vertex user interface, HyP3 provides a RESTful API and a python software developers kit (SDK) to allow programmatic access and the ability to build HyP3 into user workflows. HyP3 is open source and designed to allow users to develop new processing plugins or stand up their own custom processing pipeline.</p><p>We will present an overview of using HyP3, both inside Vertex and programmatically, and the available output products. We will demonstrate using HyP3 to investigate the consequences of natural hazards and very briefly discuss the technologies and software design principles used in the development of HyP3 and how users could contribute new plugins, or stand up their own custom processing pipeline.</p>


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