Asynchronous behavior of outlet glaciers feeding Godthåbsfjord (Nuup Kangerlua) and the triggering of Narsap Sermia's retreat in SW Greenland

Roman J. Motyka; Ryan Cassotto; Martin Truffer; Kristian Kjellerup Kjeldsen; Dirk van As; Niels Jákup Korsgaard; Mark Fahnestock; Ian Howat; Peter Lang Langen; John Mortensen; Kunuk Lennert; Søren Rysgaard

doi:10.1017/jog.2016.138

Asynchronous behavior of outlet glaciers feeding Godthåbsfjord (Nuup Kangerlua) and the triggering of Narsap Sermia's retreat in SW Greenland

Roman J. Motyka, Ryan Cassotto, Martin Truffer, Kristian Kjellerup Kjeldsen, Dirk van As, Niels Jákup Korsgaard, Mark Fahnestock, Ian Howat, Peter Lang Langen, John Mortensen, Kunuk Lennert, Søren Rysgaard

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Abstract

We assess ice loss and velocity changes between 1985 and 2014 of three tidewater and five-land terminating glaciers in Godthåbsfjord (Nuup Kangerlua), Greenland. Glacier thinning accounted for 43.8 ± 0.2 km³ of ice loss, equivalent to 0.10 mm eustatic sea-level rise. An additional 3.5 ± 0.3 km³ was lost to the calving retreats of Kangiata Nunaata Sermia (KNS) and Narsap Sermia (NS), two tidewater glaciers that exhibited asynchronous behavior over the study period. KNS has retreated 22 km from its Little Ice Age (LIA) maximum (1761 AD), of which 0.8 km since 1985. KNS has stabilized in shallow water, but seasonally advects a 2 km long floating tongue. In contrast, NS began retreating from its LIA moraine in 2004-06 (0.6 km), re-stabilized, then retreated 3.3 km during 2010-14 into an over-deepened basin. Velocities at KNS ranged 5-6 km a^-1, while at NS they increased from 1.5 to 5.5 km a^-1 between 2004 and 2014. We present comprehensive analyses of glacier thinning, runoff, surface mass balance, ocean conditions, submarine melting, bed topography, ice mélange and conclude that the 2010-14 NS retreat was triggered by a combination of factors but primarily by an increase in submarine melting.

Original language	English
Journal	Journal of Glaciology
Volume	63
Issue number	238
Pages (from-to)	288-308
Number of pages	21
ISSN	0022-1430
DOIs	https://doi.org/10.1017/jog.2016.138
Publication status	Published - 1 Apr 2017

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Motyka, R. J., Cassotto, R., Truffer, M., Kjeldsen, K. K., van As, D., Korsgaard, N. J., Fahnestock, M., Howat, I., Langen, P. L., Mortensen, J., Lennert, K., & Rysgaard, S. (2017). Asynchronous behavior of outlet glaciers feeding Godthåbsfjord (Nuup Kangerlua) and the triggering of Narsap Sermia's retreat in SW Greenland. Journal of Glaciology, 63(238), 288-308. https://doi.org/10.1017/jog.2016.138

Motyka, RJ, Cassotto, R, Truffer, M, Kjeldsen, KK, van As, D, Korsgaard, NJ, Fahnestock, M, Howat, I, Langen, PL, Mortensen, J, Lennert, K & Rysgaard, S 2017, 'Asynchronous behavior of outlet glaciers feeding Godthåbsfjord (Nuup Kangerlua) and the triggering of Narsap Sermia's retreat in SW Greenland', Journal of Glaciology, vol. 63, no. 238, pp. 288-308. https://doi.org/10.1017/jog.2016.138

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title = "Asynchronous behavior of outlet glaciers feeding Godth{\aa}bsfjord (Nuup Kangerlua) and the triggering of Narsap Sermia's retreat in SW Greenland",

abstract = "We assess ice loss and velocity changes between 1985 and 2014 of three tidewater and five-land terminating glaciers in Godth{\aa}bsfjord (Nuup Kangerlua), Greenland. Glacier thinning accounted for 43.8 ± 0.2 km3 of ice loss, equivalent to 0.10 mm eustatic sea-level rise. An additional 3.5 ± 0.3 km3 was lost to the calving retreats of Kangiata Nunaata Sermia (KNS) and Narsap Sermia (NS), two tidewater glaciers that exhibited asynchronous behavior over the study period. KNS has retreated 22 km from its Little Ice Age (LIA) maximum (1761 AD), of which 0.8 km since 1985. KNS has stabilized in shallow water, but seasonally advects a 2 km long floating tongue. In contrast, NS began retreating from its LIA moraine in 2004-06 (0.6 km), re-stabilized, then retreated 3.3 km during 2010-14 into an over-deepened basin. Velocities at KNS ranged 5-6 km a-1, while at NS they increased from 1.5 to 5.5 km a-1 between 2004 and 2014. We present comprehensive analyses of glacier thinning, runoff, surface mass balance, ocean conditions, submarine melting, bed topography, ice m{\'e}lange and conclude that the 2010-14 NS retreat was triggered by a combination of factors but primarily by an increase in submarine melting.",

author = "Motyka, {Roman J.} and Ryan Cassotto and Martin Truffer and Kjeldsen, {Kristian Kjellerup} and {van As}, Dirk and Korsgaard, {Niels J{\'a}kup} and Mark Fahnestock and Ian Howat and Langen, {Peter Lang} and John Mortensen and Kunuk Lennert and S{\o}ren Rysgaard",

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T1 - Asynchronous behavior of outlet glaciers feeding Godthåbsfjord (Nuup Kangerlua) and the triggering of Narsap Sermia's retreat in SW Greenland

AU - Motyka, Roman J.

AU - Cassotto, Ryan

AU - Truffer, Martin

AU - Kjeldsen, Kristian Kjellerup

AU - van As, Dirk

AU - Korsgaard, Niels Jákup

AU - Fahnestock, Mark

AU - Howat, Ian

AU - Langen, Peter Lang

AU - Mortensen, John

AU - Lennert, Kunuk

AU - Rysgaard, Søren

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N2 - We assess ice loss and velocity changes between 1985 and 2014 of three tidewater and five-land terminating glaciers in Godthåbsfjord (Nuup Kangerlua), Greenland. Glacier thinning accounted for 43.8 ± 0.2 km3 of ice loss, equivalent to 0.10 mm eustatic sea-level rise. An additional 3.5 ± 0.3 km3 was lost to the calving retreats of Kangiata Nunaata Sermia (KNS) and Narsap Sermia (NS), two tidewater glaciers that exhibited asynchronous behavior over the study period. KNS has retreated 22 km from its Little Ice Age (LIA) maximum (1761 AD), of which 0.8 km since 1985. KNS has stabilized in shallow water, but seasonally advects a 2 km long floating tongue. In contrast, NS began retreating from its LIA moraine in 2004-06 (0.6 km), re-stabilized, then retreated 3.3 km during 2010-14 into an over-deepened basin. Velocities at KNS ranged 5-6 km a-1, while at NS they increased from 1.5 to 5.5 km a-1 between 2004 and 2014. We present comprehensive analyses of glacier thinning, runoff, surface mass balance, ocean conditions, submarine melting, bed topography, ice mélange and conclude that the 2010-14 NS retreat was triggered by a combination of factors but primarily by an increase in submarine melting.

AB - We assess ice loss and velocity changes between 1985 and 2014 of three tidewater and five-land terminating glaciers in Godthåbsfjord (Nuup Kangerlua), Greenland. Glacier thinning accounted for 43.8 ± 0.2 km3 of ice loss, equivalent to 0.10 mm eustatic sea-level rise. An additional 3.5 ± 0.3 km3 was lost to the calving retreats of Kangiata Nunaata Sermia (KNS) and Narsap Sermia (NS), two tidewater glaciers that exhibited asynchronous behavior over the study period. KNS has retreated 22 km from its Little Ice Age (LIA) maximum (1761 AD), of which 0.8 km since 1985. KNS has stabilized in shallow water, but seasonally advects a 2 km long floating tongue. In contrast, NS began retreating from its LIA moraine in 2004-06 (0.6 km), re-stabilized, then retreated 3.3 km during 2010-14 into an over-deepened basin. Velocities at KNS ranged 5-6 km a-1, while at NS they increased from 1.5 to 5.5 km a-1 between 2004 and 2014. We present comprehensive analyses of glacier thinning, runoff, surface mass balance, ocean conditions, submarine melting, bed topography, ice mélange and conclude that the 2010-14 NS retreat was triggered by a combination of factors but primarily by an increase in submarine melting.

U2 - 10.1017/jog.2016.138

DO - 10.1017/jog.2016.138

M3 - Journal article

SN - 0022-1430

VL - 63

SP - 288

EP - 308

JO - Journal of Glaciology

JF - Journal of Glaciology

IS - 238

ER -

Asynchronous behavior of outlet glaciers feeding Godthåbsfjord (Nuup Kangerlua) and the triggering of Narsap Sermia's retreat in SW Greenland

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