Firn data compilation reveals widespread decrease of firn air content in western Greenland

• Published in: The Cryosphere
• Main Authors: B. Vandecrux, M. MacFerrin, H. Machguth, W. T. Colgan, D. van As, A. Heilig, C. M. Stevens, C. Charalampidis, R. S. Fausto, E. M. Morris, E. Mosley-Thompson, L. Koenig, L. N. Montgomery, C. Miège, S. B. Simonsen, T. Ingeman-Nielsen, J. E. Box
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2019
• Subjects: Environmental sciences; GE1-350; Geology; QE1-996.5; Greenland; Ice Sheet; The Cryosphere
• Online Access: https://doi.org/10.5194/tc-13-845-2019; https://doaj.org/article/eb4b8959b0aa4486b514832fee75a5f8

A porous layer of multi-year snow known as firn covers the Greenland-ice-sheet interior. The firn layer buffers the ice-sheet contribution to sea-level rise by retaining a fraction of summer melt as liquid water and refrozen ice. In this study we quantify the Greenland ice-sheet firn air content (FAC), an indicator of meltwater retention capacity, based on 360 point observations. We quantify FAC in both the uppermost 10 m and the entire firn column before interpolating FAC over the entire ice-sheet firn area as an empirical function of long-term mean air temperature ( <math xmlns="http://www.w3.org/1998/Math/MathML" id="M1" display="inline" overflow="scroll" dspmath="mathml"><mover accent="true"><mrow><msub><mi>T</mi><mtext>a</mtext></msub></mrow><mo mathvariant="normal">‾</mo></mover></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="12pt" height="16pt" class="svg-formula" dspmath="mathimg" md5hash="3f34f2e28fd131f1588d0a4a19d8cca4"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="tc-13-845-2019-ie00001.svg" width="12pt" height="16pt" src="tc-13-845-2019-ie00001.png"/></svg:svg> ) and net snow accumulation ( <math xmlns="http://www.w3.org/1998/Math/MathML" id="M2" display="inline" overflow="scroll" dspmath="mathml"><mrow><mover accent="true"><mover accent="true"><mi>c</mi><mo mathvariant="normal">˙</mo></mover><mo mathvariant="normal">‾</mo></mover><mo>)</mo></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="12pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="2467b5ce9e85c5b99553be3356b76c30"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="tc-13-845-2019-ie00002.svg" width="12pt" height="15pt" src="tc-13-845-2019-ie00002.png"/></svg:svg> . We estimate a total ice-sheet-wide FAC of 26 800±1840 km 3 , of which 6500±450 km ...