University of Oulu

Irvine-Fynn, T. D. L., Bunting, P., Cook, J. M., Hubbard, A., Barrand, N. E., Hanna, E., Hardy, A. J., Hodson, A. J., Holt, T. O., Huss, M., McQuaid, J. B., Nilsson, J., Naegeli, K., Roberts, O., Ryan, J. C., Tedstone, A. J., Tranter, M., & Williamson, C. J. (2021). Temporal Variability of Surface Reflectance Supersedes Spatial Resolution in Defining Greenland’s Bare-Ice Albedo. Remote Sensing, 14(1), 62.

Temporal variability of surface reflectance supersedes spatial resolution in defining Greenland’s bare-ice albedo

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Author: Irvine-Fynn, Tristram D. L.1; Bunting, Pete1; Cook, Joseph M.2;
Organizations: 1Department of Geography and Earth Sciences, Aberystwyth University, Aberystwyth SY23 3DB, UK
2Department of Environmental Science, Aarhus University, DK-4000 Roskilde, Denmark
3Centre for Arctic Gas Hydrate, Environment and Climate, UiT—The Arctic University of Norway, 9019 Tromso, Norway
4Department of Geography, University of Oulu, FI-90014 Oulu, Finland
5School of Geography Earth and Environmental Sciences, University of Birmingham, Birmingham B15 2TT, UK
6Lincoln Climate Research Group, School of Geography, University of Lincoln, Lincoln LN6 7DW, UK
7Department of Arctic Geology, University Centre in Svalbard (UNIS), N-9171 Longyearbyen, Norway
8Department of Environmental Sciences, Western Norway University of Applied Sciences, 6856 Sogndal, Norway
9Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), CH-8903 Birmensdorf, Switzerland
10Laboratory of Hydraulics, Hydrology and Glaciology (VAW), ETH Zurich, CH-8093 Zurich, Switzerland
11Department of Geosciences, University of Fribourg, CH-1700 Fribourg, Switzerland
12School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK
13Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
14Institute of Geography, Universität Bern, CH-3012 Bern, Switzerland
15Remote Sensing Laboratories, Department of Geography, University of Zürich, CH-8057 Zurich, Switzerland
16Department of Geography, University of Oregon, Eugene, OR 97403, USA
17School of Geographical Sciences, University of Bristol, Bristol BS8 1SS, UK
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 5.5 MB)
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Language: English
Published: Multidisciplinary Digital Publishing Institute, 2022
Publish Date: 2022-05-17


Ice surface albedo is a primary modulator of melt and runoff, yet our understanding of how reflectance varies over time across the Greenland Ice Sheet remains poor. This is due to a disconnect between point or transect scale albedo sampling and the coarser spatial, spectral and/or temporal resolutions of available satellite products. Here, we present time-series of bare-ice surface reflectance data that span a range of length scales, from the 500 m for Moderate Resolution Imaging Spectrometer’s MOD10A1 product, to 10 m for Sentinel-2 imagery, 0.1 m spot measurements from ground-based field spectrometry, and 2.5 cm from uncrewed aerial drone imagery. Our results reveal broad similarities in seasonal patterns in bare-ice reflectance, but further analysis identifies short-term dynamics in reflectance distribution that are unique to each dataset. Using these distributions, we demonstrate that areal mean reflectance is the primary control on local ablation rates, and that the spatial distribution of specific ice types and impurities is secondary. Given the rapid changes in mean reflectance observed in the datasets presented, we propose that albedo parameterizations can be improved by (i) quantitative assessment of the representativeness of time-averaged reflectance data products, and, (ii) using temporally-resolved functions to describe the variability in impurity distribution at daily time-scales. We conclude that the regional melt model performance may not be optimally improved by increased spatial resolution and the incorporation of sub-pixel heterogeneity, but instead, should focus on the temporal dynamics of bare-ice albedo.

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Series: Remote sensing
ISSN: 2072-4292
ISSN-E: 2072-4292
ISSN-L: 2072-4292
Volume: 14
Issue: 1
Article number: 62
DOI: 10.3390/rs14010062
Type of Publication: A1 Journal article – refereed
Field of Science: 519 Social and economic geography
Funding: This research was funded by NERC’s Large Grant ‘Black and Bloom’ (NE/M020991/1, NE/M021025/1, NE/M021084/1 and NE/M020770/1) supporting T.D.L.I.-F., J.M.C., E.H., A.J.H. (Andrew J. Hodson), J.B.M., J.N., A.J.T., M.T., C.J.W.; T.D.L.I.-F. acknowledges Leverhulme Trust Research Fellowship RF-2018-584/4; K.N. acknowledges SNSF Mobility Fellowship Grant (P2FRP2/174888); A.H. acknowledges a research professorship from the Research Council of Norway through its Centres of Excellence scheme (Grant 223259) and an Academy of Finland visiting fellowship to the University of Oulu. J.N. was supported by the NASA MEaSUREs ITS_LIVE project, the NASA Cryospheric Sciences program the Jet Propulsion Laboratory, California Institute of Technology, through an agreement with the National Aeronautics and Space Administration.
Copyright information: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (