Drainage basin delineation for outlet glaciers of Northeast Greenland based on Sentinel-1 ice velocities and TanDEM-X elevations

Krieger, Lukas; Floricioiu, Dana; Neckel, Niklas

doi:10.1016/j.rse.2019.111483

Cited by 39 publications

(32 citation statements)

References 33 publications

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“…For the present study, we used the geometric extent of the drainage area of each single glacier derived by Krieger et al [9] based on ice flow direction and slope information. Over the termini of the glaciers of interest, the surface elevation change rate (SECR) was derived from temporally separated InSAR measurements by TDM.…”

Section: Methodsmentioning

confidence: 99%

“…To assign the SECR measurements to the individual outlet glaciers, we used catchments which were calculated by a modified watershed algorithm from TDM global DEM elevations and Sentinel-1 velocity measurements in areas of fast ice flow described by Krieger et al [9]. The seaward catchment extent was bounded by manually delineated calving fronts on the respective backscattering amplitude images and DInSAR grounding lines from March 2011 and Janary 2014 (Section S1).…”

Section: Volume To Mass Conversionmentioning

confidence: 99%

“…This fast moving ice stream extends more than 600 km to the interior of the GrIS and is drained by four major outlet glaciers: Nioghalvfjerdsfjorden (79North), Zachariae Isstrøm (ZI), Kofoed-Hansen Brae and Storstrømmen. The two glaciers 79North and ZI alone drain approximately 12% of the total GrIS area [9] and dynamic changes at their termini can therefore cause a considerable mass loss and contribution to global sea level rise. To characterise and model Greenland's reaction to changed environmental forcing, mass balance estimates are derived from volumetric measurements (geodetic method) [10][11][12], the mass-budget method [13,14] and with gravimetric techniques [15,16].…”

Section: Introductionmentioning

confidence: 99%

“…Mass change observations have also been produced with altimetry for these two glaciers with ERS-2 during 1996-2001 and ICESat during 2003-2008 [10]. Until recently, a challenge in investigating individual outlet glaciers of the ice sheets was to determine their spatial extent because no consistent set of drainage basins was available and ice sheet sectors have been separated mostly at clearly identifiable ice divides in digital elevation models (DEMs) [9,19].…”

Section: Introductionmentioning

confidence: 99%

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Synergistic Use of Single-Pass Interferometry and Radar Altimetry to Measure Mass Loss of NEGIS Outlet Glaciers between 2011 and 2014

et al. 2020

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Mass balances of individual glaciers on ice sheets have been previously reported by forming a mass budget of discharged ice and modelled ice sheet surface mass balance or a complementary method which measures volume changes over the glaciated area that are subsequently converted to glacier mass change. On ice sheets, volume changes have been measured predominantly with radar and laser altimeters but InSAR DEM differencing has also been applied on smaller ice bodies. Here, we report for the first time on the synergistic use of volumetric measurements from the CryoSat-2 radar altimetry mission together with TanDEM-X DEM differencing and calculate the mass balance of the two major outlet glaciers of the Northeast Greenland Ice Stream: Zachariæ Isstrøm and Nioghalvfjerdsfjorden (79North). The glaciers lost 3.59 ± 1.15 G t a − 1 and 1.01 ± 0.95 G t a − 1 , respectively, between January 2011 and January 2014. Additionally, there has been substantial sub-aqueous mass loss on Zachariæ Isstrøm of more than 11 G t a − 1 . We attribute the mass changes on both glaciers to dynamic downwasting. The presented methodology now permits using TanDEM-X bistatic InSAR data in the context of geodetic mass balance investigations for large ice sheet outlet glaciers. In the future, this will allow monitoring the mass changes of dynamic outlet glaciers with high spatial resolution while the superior vertical accuracy of CryoSat-2 can be used for the vast accumulation zones in the ice sheet interior.

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Section: Methodsmentioning

confidence: 99%

Section: Volume To Mass Conversionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Synergistic Use of Single-Pass Interferometry and Radar Altimetry to Measure Mass Loss of NEGIS Outlet Glaciers between 2011 and 2014

et al. 2020

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“…Ice flow models, for example, by Choi et al (2017) indicate that 79NG is less vulnerable than ZI due to its upward sloping bed close to the present ground line and a series of pinning points close to the calving front (Choi et al, 2017). Satellite‐derived data suggest that ZI is actually at its tipping point and 79NG very close to it (Krieger et al, 2020; Mouginot et al, 2015, 2019).…”

Section: Introduction and Regional Settingmentioning

confidence: 99%

Holocene Interactions Between Glacier Retreat, Sea Ice Formation, and Atlantic Water Advection at the Inner Northeast Greenland Continental Shelf

Syring

Lloyd

Stein

et al. 2020

Paleoceanog and Paleoclimatol

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During the past four decades significant decrease in Arctic sea ice and a dramatic ice mass loss of the Greenland Ice Sheet (GIS) has been coincident with global warming and an increase in atmospheric CO2. In Northeast Greenland significant mass loss from the outlet glaciers Nioghalvfjerdsbrae (79NG) and Zachariae Isstrøm (ZI) and intensive seasonal breakup of the local Norske Øer Ice Barrier (NØIB) have also been observed since 2000. In order to better understand the processes driving these modern changes, studies of paleoclimate records are important and of major societal relevance. A multiproxy study including organicbiogeochemical and micropaleontological proxies was carried out on a marine sediment core recovered directly in front of 79NG. Data from Core PS100/270 evidenced a strong inflow of warm recirculating Atlantic Water across the Northeast Greenland shelf from the early

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The impact of ice base topography, basal channels and subglacial discharge on basal melting --- an exemplary numerical study for the floating ice tongue of the 79◦ North Glacier

Aragh

Klingbeil

Zeising

et al. 2022

Preprint

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Realistically approximating the basal melting of ice shelves is critical for reliable climate model projections and the process representations in ice-ocean interaction. In this regard, extensive research attributes the massive thinning of vulnerable ice shelves to basal melting enhancement driven by ocean water warming, focusing mainly on oceanic warm water intrusion into the sub-shelf basins. However, climate models mainly underestimated the impacts of probable small-scale processes at the ice-ocean interface on basal melting by using smooth ice base topographies. This paper provides new insights into how smallscale features on the ice-ocean interface contribute to basal melting enhancement and spatial distribution. We developed a time-dependent, two-dimensional ice-shelf plume model as an optimal tool that allows a high-resolution representation of basal topography and with the unique ability to provide valuable information from the mixed boundary layer between ocean and ice shelves. In an exemplary case study for the floating ice tongue of the 79* North Glacier, systematic sensitive analyses were performed with the developed model. Our results show that the sub-km-scale basal channels with realistic dimensions increase the mean basal melt rate and generate extreme and sizeable lateral variability of melting at the grounding line. This mechanism is not reproducible with the tuning of drag coefficient. Besides, it reveals that the subglacial discharge in the channels has contradicting effects of reducing the melt rate by refreshing the sea water and increasing the freezing point while increasing the melt rate due to high water speed. However, the latter was dominant in our experiments.

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Drainage basin delineation for outlet glaciers of Northeast Greenland based on Sentinel-1 ice velocities and TanDEM-X elevations

Cited by 39 publications

References 33 publications

Synergistic Use of Single-Pass Interferometry and Radar Altimetry to Measure Mass Loss of NEGIS Outlet Glaciers between 2011 and 2014

Synergistic Use of Single-Pass Interferometry and Radar Altimetry to Measure Mass Loss of NEGIS Outlet Glaciers between 2011 and 2014

Holocene Interactions Between Glacier Retreat, Sea Ice Formation, and Atlantic Water Advection at the Inner Northeast Greenland Continental Shelf

The impact of ice base topography, basal channels and subglacial discharge on basal melting --- an exemplary numerical study for the floating ice tongue of the 79◦ North Glacier

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