Surface Melting Drives Fluctuations in Airborne Radar Penetration in West Central Greenland

Inès N. Otosaka; Andrew Shepherd; Tânia G.D. Casal; Alex Coccia; Malcolm Davidson; Alessandro Di Bella; Xavier Fettweis; René Forsberg; Veit Helm; Anna E. Hogg; Sine M. Hvidegaard; Adriano Lemos; Karlus Macedo; Peter Kuipers Munneke; Tommaso Parrinello; Sebastian B. Simonsen; Henriette Skourup; Louise Sandberg Sørensen

doi:10.1029/2020GL088293

Surface Melting Drives Fluctuations in Airborne Radar Penetration in West Central Greenland

Inès N. Otosaka^*, Andrew Shepherd, Tânia G.D. Casal, Alex Coccia, Malcolm Davidson, Alessandro Di Bella, Xavier Fettweis, René Forsberg, Veit Helm, Anna E. Hogg, Sine M. Hvidegaard, Adriano Lemos, Karlus Macedo, Peter Kuipers Munneke, Tommaso Parrinello, Sebastian B. Simonsen, Henriette Skourup, Louise Sandberg Sørensen

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

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Abstract

Greenland Ice Sheet surface melting has increased since the 1990s, affecting the rheology and scattering properties of the near-surface firn. We combine firn cores and modeled firn densities with 7 years of CryoVEx airborne Ku-band (13.5 GHz) radar profiles to quantify the impact of melting on microwave radar penetration in West Central Greenland. Although annual layers are present in the Ku-band radar profiles to depths up to 15 m below the ice sheet surface, fluctuations in summer melting strongly affect the degree of radar penetration. The extreme melting in 2012, for example, caused an abrupt 6.2 ± 2.4 m decrease in Ku-band radar penetration. Nevertheless, retracking the radar echoes mitigates this effect, producing surface heights that agree to within 13.9 cm of coincident airborne laser measurements. We also examine 2 years of Ka-band (34.5 GHz) airborne radar data and show that the degree of penetration is half that of coincident Ku-band.

Original language	English
Article number	e2020GL088293
Number of pages	9
Journal	Geophysical Research Letters
Volume	47
Issue number	17
Early online date	21 Aug 2020
DOIs	https://doi.org/10.1029/2020GL088293
Publication status	Published - 16 Sept 2020
Externally published	Yes

Keywords

altimetry
firn
Greenland
ice sheet
radar

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Geophysical Research Letters - 2020 - Otosaka - Surface Melting Drives Fluctuations in Airborne Radar Penetration in WestFinal published version, 3.79 MBLicence: CC BY-NC-ND

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Otosaka, I. N., Shepherd, A., Casal, T. G. D., Coccia, A., Davidson, M., Di Bella, A., Fettweis, X., Forsberg, R., Helm, V., Hogg, A. E., Hvidegaard, S. M., Lemos, A., Macedo, K., Kuipers Munneke, P., Parrinello, T., Simonsen, S. B., Skourup, H., & Sørensen, L. S. (2020). Surface Melting Drives Fluctuations in Airborne Radar Penetration in West Central Greenland. Geophysical Research Letters, 47(17), Article e2020GL088293. https://doi.org/10.1029/2020GL088293

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abstract = "Greenland Ice Sheet surface melting has increased since the 1990s, affecting the rheology and scattering properties of the near-surface firn. We combine firn cores and modeled firn densities with 7 years of CryoVEx airborne Ku-band (13.5 GHz) radar profiles to quantify the impact of melting on microwave radar penetration in West Central Greenland. Although annual layers are present in the Ku-band radar profiles to depths up to 15 m below the ice sheet surface, fluctuations in summer melting strongly affect the degree of radar penetration. The extreme melting in 2012, for example, caused an abrupt 6.2 ± 2.4 m decrease in Ku-band radar penetration. Nevertheless, retracking the radar echoes mitigates this effect, producing surface heights that agree to within 13.9 cm of coincident airborne laser measurements. We also examine 2 years of Ka-band (34.5 GHz) airborne radar data and show that the degree of penetration is half that of coincident Ku-band.",

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Otosaka, IN , Shepherd, A, Casal, TGD, Coccia, A, Davidson, M, Di Bella, A, Fettweis, X, Forsberg, R, Helm, V, Hogg, AE, Hvidegaard, SM, Lemos, A, Macedo, K, Kuipers Munneke, P, Parrinello, T, Simonsen, SB, Skourup, H & Sørensen, LS 2020, 'Surface Melting Drives Fluctuations in Airborne Radar Penetration in West Central Greenland', Geophysical Research Letters, vol. 47, no. 17, e2020GL088293. https://doi.org/10.1029/2020GL088293

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T1 - Surface Melting Drives Fluctuations in Airborne Radar Penetration in West Central Greenland

AU - Otosaka, Inès N.

AU - Shepherd, Andrew

AU - Casal, Tânia G.D.

AU - Coccia, Alex

AU - Davidson, Malcolm

AU - Di Bella, Alessandro

AU - Fettweis, Xavier

AU - Forsberg, René

AU - Helm, Veit

AU - Hogg, Anna E.

AU - Hvidegaard, Sine M.

AU - Lemos, Adriano

AU - Macedo, Karlus

AU - Kuipers Munneke, Peter

AU - Parrinello, Tommaso

AU - Simonsen, Sebastian B.

AU - Skourup, Henriette

AU - Sørensen, Louise Sandberg

PY - 2020/9/16

Y1 - 2020/9/16

N2 - Greenland Ice Sheet surface melting has increased since the 1990s, affecting the rheology and scattering properties of the near-surface firn. We combine firn cores and modeled firn densities with 7 years of CryoVEx airborne Ku-band (13.5 GHz) radar profiles to quantify the impact of melting on microwave radar penetration in West Central Greenland. Although annual layers are present in the Ku-band radar profiles to depths up to 15 m below the ice sheet surface, fluctuations in summer melting strongly affect the degree of radar penetration. The extreme melting in 2012, for example, caused an abrupt 6.2 ± 2.4 m decrease in Ku-band radar penetration. Nevertheless, retracking the radar echoes mitigates this effect, producing surface heights that agree to within 13.9 cm of coincident airborne laser measurements. We also examine 2 years of Ka-band (34.5 GHz) airborne radar data and show that the degree of penetration is half that of coincident Ku-band.

AB - Greenland Ice Sheet surface melting has increased since the 1990s, affecting the rheology and scattering properties of the near-surface firn. We combine firn cores and modeled firn densities with 7 years of CryoVEx airborne Ku-band (13.5 GHz) radar profiles to quantify the impact of melting on microwave radar penetration in West Central Greenland. Although annual layers are present in the Ku-band radar profiles to depths up to 15 m below the ice sheet surface, fluctuations in summer melting strongly affect the degree of radar penetration. The extreme melting in 2012, for example, caused an abrupt 6.2 ± 2.4 m decrease in Ku-band radar penetration. Nevertheless, retracking the radar echoes mitigates this effect, producing surface heights that agree to within 13.9 cm of coincident airborne laser measurements. We also examine 2 years of Ka-band (34.5 GHz) airborne radar data and show that the degree of penetration is half that of coincident Ku-band.

KW - altimetry

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KW - ice sheet

KW - radar

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JF - Geophysical Research Letters

IS - 17

M1 - e2020GL088293

ER -

Surface Melting Drives Fluctuations in Airborne Radar Penetration in West Central Greenland

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Keywords

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