50 MHz helicopter-borne radar data for determination of glacier thermal regime in the central Chilean Andes

Gacitúa, Guisella; Uribe, José Darío; Wilson, Ryan; Loriaux, Thomas; Hernández, Jorge Martín Rodríguez; Rivera, Andrés

doi:10.3189/2015aog70a953

Cited by 21 publications

(21 citation statements)

References 42 publications

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“…We focus on three main tasks: first, identifying subglacial water at the ice base; second, defining and characterising the modern subglacial hydrological network; and third, simulating the subglacial flow routing. We identify subglacial lakes by analysing the power of the reflected energy from the ice-bed interface (Gades et al, 2000), i.e. bed reflection power (BRP), using four steps:…”

Section: Methodsmentioning

confidence: 99%

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Subglacial lakes and hydrology across the Ellsworth Subglacial Highlands, West Antarctica

et al. 2020

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Abstract. Subglacial water plays an important role in ice sheet dynamics and stability. Subglacial lakes are often located at the onset of ice streams and have been hypothesised to enhance ice flow downstream by lubricating the ice–bed interface. The most recent subglacial-lake inventory of Antarctica mapped nearly 400 lakes, of which ∼ 14 % are found in West Antarctica. Despite the potential importance of subglacial water for ice dynamics, there is a lack of detailed subglacial-water characterisation in West Antarctica. Using radio-echo sounding data, we analyse the ice–bed interface to detect subglacial lakes. We report 33 previously uncharted subglacial lakes and present a systematic analysis of their physical properties. This represents a ∼ 40 % increase in subglacial lakes in West Antarctica. Additionally, a new digital elevation model of basal topography of the Ellsworth Subglacial Highlands was built and used to create a hydropotential model to simulate the subglacial hydrological network. This allows us to characterise basal hydrology, determine subglacial water catchments and assess their connectivity. We show that the simulated subglacial hydrological catchments of the Rutford Ice Stream, Pine Island Glacier and Thwaites Glacier do not correspond to their ice surface catchments.

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Section: Methodsmentioning

confidence: 99%

“…We calculate the BRP following previous studies (e.g. Gades et al, 2000;Gacitúa et al, 2015), as the ratio of the locally measured power of the basal echo (BRP m ) to the energy corrected by geometrical spreading and ice attenuation loss (BRP e ):…”

Section: Bed Reflection Power (Brp)mentioning

confidence: 99%

Subglacial lakes and hydrology across the Ellsworth Subglacial Highlands, West Antarctica

et al. 2020

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“…The standard deviation (σ) was calculated within 40 samples around a particular point to ensure a representative number of radar observations are included. A low value of σ indicates a smooth surface is present at the base of the ice as would be expected for the surface of a water body (Rivera et al, 2015;Gacitúa et al, 2015;Carter et al, 2007;Bowling et al, 2019).…”

Section: Specularity Calculationmentioning

confidence: 95%

Subglacial lakes and hydrology across the Ellsworth Subglacial Highlands, West Antarctica

Napoleoni¹,

Jamieson²,

Ross³

et al. 2020

Preprint

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Abstract. Subglacial water plays an important role in ice sheet dynamics and stability. It is often located at the onset of ice streams and has the potential to enhance ice flow downstream by lubricating the ice-bed interface. The most recent subglacial lake inventory of Antarctica mapped nearly 400 lakes, of which ~ 14 % are found in West Antarctica. Despite the potential importance of subglacial water for ice dynamics, there is a lack of detailed subglacial water characterization in West Antarctica. Using radio-echo sounding data, we analyse the ice-bed interface to detect subglacial lakes. We report 37 previously uncharted subglacial lakes and present a systematic analysis of their physical properties. This represents a ~ 60 % increase in subglacial lakes in the region. Additionally, a new digital elevation model of basal topography was built and used to create a detailed hydropotential model of Ellsworth Subglacial Highlands to simulate the subglacial hydrological network. This approach allows us to characterize basal hydrology, subglacial water catchments and connections between them. Furthermore, the simulated subglacial hydrological catchments of Rutford Ice Stream, Pine Island Glacier and Thwaites Glacier do not match precisely with their ice surface catchments.

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“…Glaciers in the central Andes are shrinking and down wasting as a consequence of climate warming and changes in precipitation patterns (Masiokas et al 2006;Bodin et al 2010;Gacitua et al 2015;Malmros et al 2016). Although initially increasing, ice melt runoff will begin to reduce in the future as lowest elevation land ice disappears.…”

Section: Drivers Of Change On Snow Cover Variablesmentioning

confidence: 99%

Snow cover and snow albedo changes in the central Andes of Chile and Argentina from daily MODIS observations (2000–2016)

Malmros

Mernild

Wilson

et al. 2018

Remote Sensing of Environment

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The variables of snow cover extent (SCE), snow cover duration (SCD), and snow albedo (SAL) are primary factors determining the surface energy balance and hydrological response of the cryosphere, influencing snow pack and glacier mass-balance, melt, and runoff conditions. This study examines spatiotemporal patterns and trends in SCE, SCD, and SAL (2000-2016; 16 years) for central Chilean and Argentinean Andes using the MODIS MOD10A1 C6 daily snow product. Observed changes in these variables are analyzed in relation to climatic variability by using ground truth observations (meteorological data from the El Yeso Embalse and Valle Nevado weather stations) and the Multivariate El Niño index (MEI) data. We identified significant downward trends in both SCE and SAL, especially during the onset and offset of snow seasons. SCE and SAL showed high inter-annual variability which correlate significantly with MEI applied with a one-month time-lag. SCE and SCD decreased by an average of ~13 ± 2 % and 43 ± 20 days respectively, over the study period. Analysis of spatial pattern of SCE indicates a slightly greater reduction on the eastern side (~14 ± 2 %) of the Andes Cordillera compared to the western side (~12 ± 3 %). The downward SCE, SAL, and SCD trends identified in this study are likely to have adverse impacts on downstream water resource availability to agricultural and densely populated regions in central Chile and Argentina.

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50 MHz helicopter-borne radar data for determination of glacier thermal regime in the central Chilean Andes

Cited by 21 publications

References 42 publications

Subglacial lakes and hydrology across the Ellsworth Subglacial Highlands, West Antarctica

Subglacial lakes and hydrology across the Ellsworth Subglacial Highlands, West Antarctica

Subglacial lakes and hydrology across the Ellsworth Subglacial Highlands, West Antarctica

Snow cover and snow albedo changes in the central Andes of Chile and Argentina from daily MODIS observations (2000–2016)

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