Mapping Firn Saturation Over Greenland Using NASA&#x2019;s Soil Moisture Active Passive Satellite

Julie Z. Miller; David G. Long; Christopher A. Shuman; Riley Culberg; Molly Hardman; Mary J. Brodzik

doi:10.1109/JSTARS.2022.3154968

IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing (Jan 2022)

Mapping Firn Saturation Over Greenland Using NASA’s Soil Moisture Active Passive Satellite

Julie Z. Miller,
David G. Long,
Christopher A. Shuman,
Riley Culberg,
Molly Hardman,
Mary J. Brodzik

Affiliations

Julie Z. Miller: ORCiD; Earth Science and Observation Center, Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, CO, USA
David G. Long: ORCiD; Department of Electrical and Computer Engineering, Brigham Young University, Provo, UT, USA
Christopher A. Shuman: ORCiD; Baltimore County at NASA’s Goddard Space Flight Center, University of Maryland, Greenbelt, MD, USA
Riley Culberg: ORCiD; Department of Electrical Engineering, Stanford University, Stanford, CA, USA
Molly Hardman: ORCiD; National Snow and Ice Data Center, Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, CO, USA
Mary J. Brodzik: ORCiD; National Snow and Ice Data Center, Cooperative Institute for Research in Environmental Sciences, University of Colorado Boulder, Boulder, CO, USA

DOI: https://doi.org/10.1109/JSTARS.2022.3154968
Journal volume & issue: Vol. 15
pp. 3714 – 3729

Abstract

Read online

Mapping the spatial extent of recently identified englacial hydrological features (i.e., ice slabs and perennial firn aquifers) formed by meters-thick water-saturated firn layers over the percolation facies of the Greenland Ice Sheet using L-band microwave radiometry has recently been demonstrated. However, these initial maps are binary, and do not provide a parameter to estimate the spatial variability in the thickness and volumetric fraction of meltwater stored within the firn pore space. Here, we exploit enhanced-resolution vertical-polarization L-band brightness temperature ($T_{V}^{B}$) imagery (2015–2019) generated using observations collected over Greenland by NASA’s Soil Moisture Active Passive (SMAP) satellite and a simple two-layer L-band brightness temperature model. We map water-saturated firn layers via a “firn saturation” parameter, and interpret our results together with ice slab and perennial firn aquifer spatial extents, estimates of snow accumulation simulated via the Regional Atmospheric Climate Model (RACMOp2.3), and airborne radar surveys collected via NASA’s Operation IceBridge (OIB) campaigns. We find that variable firn saturation parameter values are mapped in lower snow accumulation ice slab areas in western, northern, and northeastern Greenland, where firn is colder and water-saturated firn layers seasonally refreeze as solid-ice. Higher firn saturation parameter values are mapped in higher snow accumulation perennial firn aquifer areas in southeastern, southern, and northwestern Greenland, where firn is near the melting point, and meters-thick water-saturated firn layers exist. Our results have implications for identifying expansive englacial reservoirs that store significant volumes of meltwater in locations that are vulnerable to meltwater-induced hydrofracturing and accelerated outlet glacier flow year-round.

Published in IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing

ISSN: 1939-1404 (Print); 2151-1535 (Online)
Publisher: IEEE
Country of publisher: United States
LCC subjects: Technology: Ocean engineering; Science: Physics: Geophysics. Cosmic physics
Website: https://ieeexplore.ieee.org/xpl/RecentIssue.jsp?punumber=4609443

About the journal

Abstract

Keywords