Mapping the grounding zone of Larsen C Ice Shelf,  Antarctica, from ICESat-2 laser altimetry

Li, Tian; Dawson, Geoffrey; Chuter, Stephen; Bamber, Jonathan

doi:10.5194/tc-14-3629-2020

Cited by 16 publications

(39 citation statements)

References 34 publications

(77 reference statements)

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“…6), obvious topographical patterns and flat terrain can be found in the mountain environments and ice sheet interior, respectively. On the Antarctic Peninsula, good agreement can be found between the grounding line locations determined from ICESat-2 in Li et al (2020) and the ice shelf limit is visually identified from the shaded relief map (Fig. 6b).…”

Section: General Attributes Of Icesat-2 Demmentioning

confidence: 57%

A fine-scale digital elevation model of Antarctica derived from ICESat-2

Shen

Fan

et al. 2021

Preprint

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Abstract. Antarctic digital elevation models (DEMs) are essential for human fieldwork, ice topography monitoring and ice mass change estimation. In the past thirty decades, several Antarctic DEMs derived from satellite data have been published. However, these DEMs either have coarse spatial resolutions or vague time stamps, which limit their further scientific applications. In this study, the new-generation satellite laser altimeter Ice, Cloud, And Land Elevation Satellite-2 (ICESat-2) is used to generate a fine-scale and specific time-stamped Antarctic DEM for both the ice sheet and ice shelves. Approximately 4.69 × 109 ICESat-2 measurement points from November 2018 to November 2019 are used to estimate surface elevations at resolutions of 250 m, 500 m and 1 km based on a spatiotemporal fitting method, which results in a modal resolution of 250 m for this DEM. Approximately 74 % of Antarctica is observed, and the remaining observation gaps are interpolated using the ordinary kriging method. National Aeronautics and Space Administration Operation IceBridge (OIB) airborne data are used to evaluate the generated Antarctic DEM (hereafter called the ICESat-2 DEM) in individual Antarctic regions and surface types. Overall, a median bias of 0.11 m and a root-mean-square deviation of 8.27 m result from approximately 1.4 × 105 spatiotemporally matched grid cells. The accuracy and uncertainty of the ICESat-2 DEM vary in relation to the surface slope and roughness, and more reliable estimates are found in the flat ice sheet interior. The ICESat-2 DEM is superior to previous DEMs derived from satellite altimeters for both spatial resolution and elevation accuracy and comparable to those derived from stereo-photogrammetry and interferometry. The decimeter-scale accuracy and specific time stamp make the ICESat-2 DEM an essential addition to the existing Antarctic DEM groups, and it can be further used for other scientific applications.

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Section: General Attributes Of Icesat-2 Demmentioning

confidence: 57%

A fine-scale digital elevation model of Antarctica derived from ICESat-2

Shen

Fan

et al. 2021

Preprint

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“…We processed the ATL06 elevation data using the same methods described in Li et al (2020). We did not apply the ocean tide correction to ICESat-2 ATL06 elevation and 're-tided' the ocean loading tide.…”

Section: Icesat-2 Data and Processingmentioning

confidence: 99%

“…Following the steps of repeat track generation described in Li et al (2020), the surface elevation, elevation measurement geolocations, and the reference segment geolocations of six ground tracks along each of the 1387 Reference Ground Tracks (RGTs) were categorized into nine distinct repeat-track data groups, including six single-beam repeat-track data groups and three beampair repeat-track data groups (Figs. 4a and 4b in Li et al (2020)). For each repeat-track data group, a 'nominal reference track' was calculated by averaging the locations of reference segments from all repeat tracks inside this data group.…”

Section: Repeat Track Preparationmentioning

confidence: 99%

“…The repeat track analysis and crossover analysis of satellite altimetry (Brunt et al, 2010b(Brunt et al, , 2011Bamber, 2017, 2020;Fricker and Padman, 2006;Li et al, 2020) and the differential synthetic aperture radar interferometry (DInSAR) (Brancato et al, 2020;Mohajerani et al, 2021;Rignot et al, 2016;Rignot, 1998;Scheuchl et al, 2016), use the dynamic method to detect Points F and H. Among which, DInSAR has been the most successful method of capturing Point F accurately and providing overall good spatial coverage. However, there are few regions have been measured repeatedly by DInSAR (Friedl et al, 2020;Hogg et al, 2018), while some areas have not been mapped due to orbital limitations of the satellites (Mohajerani et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

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A High-Resolution Antarctic Grounding Zone Product from ICESat-2 Laser Altimetry

Dawson

Chuter

et al. 2021

Preprint

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Abstract. The Antarctic grounding zone, which is the transition between the fully grounded ice sheet to freely floating ice shelf, plays a critical role in ice sheet instability, mass budget calculations and ice sheet model projections. It is therefore important to continuously monitor its location and migration over time. Here we present the first ICESat-2-derived high-resolution grounding zone product of the Antarctica Ice Sheet, including three important boundaries: the inland limit of tidal flexure (Point F), inshore limit of hydrostatic equilibrium (Point H) and the break-in-slope (Point Ib). This dataset was derived from automated techniques developed in this study, using ICESat-2 laser altimetry repeat tracks between 30 March 2019 and 30 September 2020. The new grounding zone product has a near complete coverage of the Antarctica Ice Sheet with a total of 21346 Point F, 18149 Point H and 36765 Point Ib identified, including the difficult to survey grounding zones, such as the fast-flowing glaciers draining into the Amundsen Sea Embayment. The locations of newly derived ICESat-2 landward limit of tidal flexure agree well with the most recent differential synthetic aperture radar interferometry (DInSAR) observations in 2018, with the mean absolute separation and standard deviation of 0.02 and 0.02 km, respectively. By comparing the ICESat-2-derived grounding zone with the previous grounding zone products, we find up-to 15 km grounding line retreat on the Crary Ice Rise of Ross Ice Shelf and the pervasive landward grounding line migration along the Amundsen Sea Embayment during the past two decades. We also identify the presence of ice plain on the Filchner-Ronne Ice Shelf and the influence of oscillating ocean tides on the grounding zone migration. The product derived from this study is available at https://doi.org/10.5523/bris.bnqqyngt89eo26qk8keckglww (Li et al., 2021) and is archived and maintained at the National Snow and Ice Data Center.

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“…In 2018, its successor, ICESat-2, was launched equipped with an improved laser altimetry system, which is expected to produce height measurements with enhanced accuracy and coverage (e.g., [11]). The first data analyses have shown its potential for cryosphere applications, such as mapping of grounding lines in Antarctica [12] or elevation and mass change assessments for the Greenland and Antarctic ice sheets [11]. However, for smaller glaciated regions like Svalbard, an evaluation of the potential of combining data from both missions through a crossover approach has not been published yet.…”

Section: Introductionmentioning

confidence: 99%

Increased Ice Thinning over Svalbard Measured by ICESat/ICESat-2 Laser Altimetry

2021

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A decade-long pronounced increase in temperatures in the Arctic, especially in the Barents Sea region, resulted in a global warming hotspot over Svalbard. Associated changes in the cryosphere are the consequence and lead to a demand for monitoring of the glacier changes. This study uses spaceborne laser altimetry data from the ICESat and ICESat-2 missions to obtain ice elevation and mass change rates between 2003–2008 and 2019. Elevation changes are derived at orbit crossover locations throughout the study area, and regional volume and mass changes are estimated using a hypsometric approach. A Svalbard-wide annual elevation change rate of −0.30 ± 0.15 m yr−1 was found, which corresponds to a mass loss rate of −12.40 ± 4.28 Gt yr−1. Compared to the ICESat period (2003–2009), thinning has increased over most regions, including the highest negative rates along the west coast and areas bordering the Barents Sea. The overall negative regime is expected to be linked to Arctic warming in the last decades and associated changes in glacier climatic mass balance. Further, observed increased thinning rates and pronounced changes at the eastern side of Svalbard since the ICESat period are found to correlate with atmospheric and oceanic warming in the respective regions.

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Mapping the grounding zone of Larsen C Ice Shelf, Antarctica, from ICESat-2 laser altimetry

Cited by 16 publications

References 34 publications

A fine-scale digital elevation model of Antarctica derived from ICESat-2

A fine-scale digital elevation model of Antarctica derived from ICESat-2

A High-Resolution Antarctic Grounding Zone Product from ICESat-2 Laser Altimetry

Increased Ice Thinning over Svalbard Measured by ICESat/ICESat-2 Laser Altimetry

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