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Assessing a multilayered dynamic firn-compaction model for Greenland with ASIRAS radar measurements

  • Sebastian B. Simonsen (a1) (a2), Lars Stenseng (a3), Guðfinna Ađalgeirsdóttir (a2), Robert S. Fausto (a4), Christine S. Hvidberg (a1) and Philippe Lucas-Picher (a2)...

A method to assess firn compaction using data collected with the Airborne SAR (Synthetic Aperture Radar)/Interferometric Radar Altimeter System (ASIRAS) is developed. For this, we develop a dynamical firn-compaction model that includes meltwater retention. Based on the ASIRAS data, which show internal layers as annual horizons in the uppermost firn, the method relies on inferring the age/ depth (internal layers) information from the radar data using a Monte Carlo inversion technique to tune in parallel both the firn model and the atmospheric forcing parameters (temperature and accumulation). The model is validated against two firn cores, and it is shown that applying both firn densities and age/ depth information for the inversion gives the most accurate understanding of model biases. The method is then applied to a 67 km section of the EGIG line forced by atmospheric output from a regional climate model using only age/depth information in the inversion step. The layers traced by the ASIRAS data are modeled with a root-mean-square error of 9 cm, which is within the estimated error of the layer tracing. This gives us confidence in applying observed annual layering from firn radar data to assess firn compaction; however, the study also indicates that our firn-model-tuning parameters are site-dependent and cannot be parameterized by temperature and accumulation alone.

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Arnaud, L, Barnola, JM and Duval, P (2000) Physical modeling of the densification of snow/firn and ice in the upper part of polar ice sheets. In Hondoh, T ed. Physics of ice core records. Hokkaido University Press, Sapporo, 285305
Arthern, RJ and Wingham, DJ (1998) The natural fluctuations of firn densification and their effect on the geodetic determination of ice sheet mass balance. Climatic Change, 40(3–4), 605624 (doi: 10.1023/A:1005320713306)
Arthern, RJ, Vaughan, DG, Rankin, AM, Mulvaney, R and Thomas, ER (2010) In situ measurements of Antarctic snow compaction compared with predictions of models. J. Geophys. Res., 115(F3), F03011 (doi: 10.1029/2009JF001306)
Barnola, JM, Pimienta, P, Raynaud, D and Korotkevich, Y (1991) CO2 climate relationship as deduced from the Vostok ice core: a re-examination based on new measurements and on a reevaluation of the air dating. Tellus B, 43(2), 8390 (doi: 10.1034/j.1600-0889.1991.t01-1-00002.x)
Benson, CS (1962) Stratigraphic studies in the snow and firn of the Greenland ice sheet. SIPRE Res. Rep. 70, 7683
Coléou, C and Lesaffre, B (1998) Irreducible water saturation in snow: experimental results in a cold laboratory. Ann. Glaciol., 26, 6468
Cuffey, KM and Paterson, WSB (2010) The physics of glaciers, 4th edn. Butterworth-Heinemann, Oxford
De la Peña, S and 9 others (2010) Spatially extensive estimates of annual accumulation in the dry snow zone of the Greenland Ice Sheet determined from radar altimetry. Cryosphere, 4(4), 467474 (doi: 10.5194/tc-4-467-2010)
Dee, DP and 35 others (2011) The ERA-Interim reanalysis: configuration and performance of the data assimilation system. Q.J.R. Meteorol. Soc., 137(656), 553597 (doi: 10.1002/qj.828)
Finsterwalder, R (1959) Exp6dition Glaciologique Internationale au Groenland 1957–60 (EGIG). J. Glaciol., 3(26), 542546
Freitag, J, Wilhelms, F and Kipfstuhl, S (2004) Microstructure-dependent densification of polar firn derived from X-ray microtomography. J. Glaciol., 50(169), 243250 (doi: 10.3189/172756504781830123)
Goujon, C, Barnola, JM and Ritz, C (2003) Modeling the densification of polar firn including heat diffusion: application to close-off characteristics and gas isotopic fractionation for Antarctica and Greenland sites. J. Geophys. Res., 108(D24), 4792 (doi: 10.1029/2002JD003319)
Hall, DK, Nghiem, SV, Schaaf, CB, DiGirolamo, NE and Neumann, G (2009) Evaluation of surface and near-surface melt characteristics on the Greenland ice sheet using MODIS and QuikSCAT data. J. Geophys. Res., 114(F4), F04006 (doi: 10.1029/2009JF001287)
Hawley, RL and Waddington, ED (2011) In situ measurements of firn compaction profiles using borehole optical stratigraphy. J. Glaciol., 57(202), 289294 (doi: 10.3189/002214311796405889)
Hawley, RL, Morris, EM, Cullen, R, Nixdorf, U, Shepherd, AP and Wingham, DJ (2006) ASIRAS airborne radar resolves internal annual layers in the dry-snow zone of Greenland. Geophys. Res. Lett., 33(4), L04502 (doi: 10.1029/2005GL025147)
Helm, V and 6 others (2007) Winter accumulation in the percolation zone of Greenland measured by airborne radar altimeter. Geophys. Res. Lett., 34(6), L06501 (doi: 10.1029/2006GL029185)
Helsen, MM and 7 others (2008) Elevation changes in Antarctica mainly determined by accumulation variability. Science, 320(5883), 16261629 (doi: 10.1126/science.1153894)
Herron, MM and Langway, CCJ (1980) Firn densification: an empirical model. J. Glaciol., 25(93), 373385
Hörhold, MW, Kipfstuhl, S, Wilhelms, F, Freitag, J and Frenzel, A (2011) The densification of layered polar firn. J. Geophys. Res., 116(F1), F01001 (doi: 10.1029/2009JF001630)
Hörhold, MW, Laepple, T, Freitag, J, Bigler, M, Fischer, H and Kipfstuhl, S (2012) On the impact of impurities on the densification of polar firn. Earth Planet. Sci. Lett., 325–326, 9399 (doi: 10.1016/j.epsl.2011.12.022)
Humphrey, NF, Harper, JT and Pfeffer, WT (2012) Thermal tracking of meltwater retention in Greenland’s accumulation area. J. Geophys. Res., 117(F1), F01010 (doi: 10.1029/2011JF002083)
Janssens, I and Huybrechts, P (2000) The treatment of meltwater retention in mass-balance parameterizations of the Greenland ice sheet. Ann. Glaciol., 31, 133140 (doi: 10.3189/172756400781819941)
Kaspers, KA, Van de Wal, RSW, Van den Broeke, MR, Schwander, J, Van Lipzig, NPM and Brenninkmeijer, CAM (2004) Model calculations of the age of firn air across the Antarctic continent. Atmos. Chem. Phys., 4(5), 13651380 (doi: 10.5194/acp-4-1365-2004)
Lemark, A (2010) A study of the Flade Isblink ice cap using a simple ice flow model. (Master’s thesis, University of Copenhagen)
Lenaerts, JTM and 6 others (2012) Modeling drifting snow in Antarctica with a regional climate model: 1. Methods and model evaluation. J. Geophys. Res., 117(D5), D05108 (doi: 10.1029/2011JD016145)
Li, J and Zwally, HJ (2004) Modeling the density variation in the shallow firn layer. Ann. Glaciol., 38, 309313 (doi: 10.3189/172756404781814988)
Li, J and Zwally, HJ (2011) Modeling of firn compaction for estimating ice-sheet mass change from observed ice-sheet elevation change. Ann. Glaciol., 52(59), 17 (doi: 10.3189/172756411799096321)
Ligtenberg, SRM, Helsen, MM and Van den Broeke, MR (2011) An improved semi-empirical model for the densification of Antarctic firn. Cryosphere, 5(4), 809819 (doi: 10.5194/tc-5-809-2011)
Lucas-Picher, P, Wulff-Nielsen, M, Christensen, JH, Aðalsgeirsdóttir, G, Mottram, R and Simonsen, SB (2012) Very high resolution regional climate model simulations over Greenland: identifying added value. J. Geophys. Res., 117(D2), D02108 (doi: 10.1029/2011JD016267)
McLachlan, G and Peel, D (2000) Finite mixture models. Wiley, Hoboken, NJ
Morris, EM and Wingham, DJ (2011) The effect of fluctuations in surface density, accumulation and compaction on elevation change rates along the EGIG line, central Greenland. J. Glaciol., 57(203), 416430 (doi: 10.3189/002214311796905613)
Mosegaard, K and Tarantola, A (1995) Monte Carlo sampling of solutions to inverse problems. J. Geophys. Res., 100(B7), 12431124 47 (doi: 10.1029/94JB03097)
Nghiem, SV and 8 others (2012) The extreme melt across the Greenland ice sheet in 2012. Geophys. Res. Lett., 39(20), L20502 (doi: 10.1029/2012GL053611)
Reeh, N (2008) A nonsteady-state firn-densification model for the percolation zone of a glacier. J. Geophys. Res., 113(F3), F03023 (doi: 10.1029/2007JF000746)
Reeh, N, Fisher, DA, Koerner RM and Clausen HB (2005) An empirical firn-densification model comprising ice lenses. Ann. Glaciol., 42, 101106 (doi: 10.3189/172756405781812871)
Schneider, T and Jansson, P (2004) Internal accumulation in firn and its significance for the mass balance of Storglaciären, Sweden. J. Glaciol., 50(168), 2534 (doi: 10.3189/172756504781830277)
Schwander, J, Sowers, T, Barnola, JM, Blunier, T, Fuchs, A and Malaizé, B (1997) Age scale of the air in the Summit ice: implication for glacial–interglacial temperature change. J. Geophys. Res., 102(D16), 19 48319 493
Simmons, A, Uppala, S, Dee, D and Kobayashi, S (2007) ERA-Interim: new ECMWF reanalysis products from 1989 onwards. ECMRWF Newsl. 110, 2535
Sørensen, LS and 7 others (2011) Mass balance of the Greenland ice sheet (2003–2008) from ICESat data – the impact of interpolation, sampling and firn density. Cryosphere, 5(1), 173186 (doi: 10.5194/tc-5-173-2011)
Steen-Larsen, HC and 23 others (2011) Understanding the climatic signal in the water stable isotope records from the NEEM shallow firn/ice cores in northwest Greenland. J. Geophys. Res., 116(D6), D06108 (doi: 10.1029/2010JD014311)
Stenseng, L (2011) Polar remote sensing by CryoSat-type radar altimetry. (PhD thesis, Technical University of Denmark)
Tarantola, A (2005) Inverse problem theory and methods for model parameter estimation. Society for Industrial and Applied Mathematics (SIAM), Philadelphia, PA
Zwally, HJ and Li, J (2002) Seasonal and interannual variations of firn densification and ice-sheet surface elevation at Greenland summit. J. Glaciol., 48(161), 199207 (doi: 10.3189/172756502781831403)
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Journal of Glaciology
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