TY - JOUR
T1 - Terminus-driven retreat of a major southwest Greenland tidewater glacier during the early 19th century: insights from glacier reconstructions and numerical modelling
AU - Lea, James M.
AU - Mair, Douglas W.F.
AU - Nick, Faezeh M.
AU - Rea, Brice R.
AU - Weidick, Anker
AU - Kjær, Kurt H.
AU - Morlighem, Mathieu
AU - van As, Dirk
AU - Schofield, J. Edward
PY - 2014/4
Y1 - 2014/4
N2 - Tidewater glaciers in Greenland experienced widespread retreat during the last century. Information on their behaviour prior to this is often poorly constrained due to lack of observations, while determining the drivers prior to instrumental records is also problematic. Here we present a record of the dynamics of Kangiata Nunaata Sermia (KNS), southwest Greenland, from its Little Ice Age maximum (LIAmax) to 1859 - the period before continuous air temperature observations began at Nuuk in 1866. Using glacial geomorphology, historical accounts, photographs and GIS analyses, we provide evidence KNS was at its LIAmax by 1761, had retreated by~5 km by 1808 and a further 7km by 1859. This predates retreat at Jakobshavn Isbræ by 43-113 years, demonstrating the asynchroneity of tidewater glacier terminus response following the LIA. We use a one-dimensional flowband model to determine the relative sensitivity of KNS to atmospheric and oceanic climate forcing. Results demonstrate that terminus forcing rather than surface mass balance drove the retreat. Modelled glacier sensitivity to submarine melt rates is also insufficient toexplain the retreat observed. However, moderate increases in crevasse water depth, driving an increase in calving,are capable of causing terminus retreat of the observed magnitude and timing.
AB - Tidewater glaciers in Greenland experienced widespread retreat during the last century. Information on their behaviour prior to this is often poorly constrained due to lack of observations, while determining the drivers prior to instrumental records is also problematic. Here we present a record of the dynamics of Kangiata Nunaata Sermia (KNS), southwest Greenland, from its Little Ice Age maximum (LIAmax) to 1859 - the period before continuous air temperature observations began at Nuuk in 1866. Using glacial geomorphology, historical accounts, photographs and GIS analyses, we provide evidence KNS was at its LIAmax by 1761, had retreated by~5 km by 1808 and a further 7km by 1859. This predates retreat at Jakobshavn Isbræ by 43-113 years, demonstrating the asynchroneity of tidewater glacier terminus response following the LIA. We use a one-dimensional flowband model to determine the relative sensitivity of KNS to atmospheric and oceanic climate forcing. Results demonstrate that terminus forcing rather than surface mass balance drove the retreat. Modelled glacier sensitivity to submarine melt rates is also insufficient toexplain the retreat observed. However, moderate increases in crevasse water depth, driving an increase in calving,are capable of causing terminus retreat of the observed magnitude and timing.
KW - Glacial geomorphology
KW - Glacier calving
KW - Glacier fluctuations
KW - Glacier modelling
UR - http://www.scopus.com/inward/record.url?scp=84903212878&partnerID=8YFLogxK
U2 - 10.3189/2014JoG13J163
DO - 10.3189/2014JoG13J163
M3 - Article
SN - 0022-1430
VL - 60
SP - 333
EP - 344
JO - Journal of Glaciology
JF - Journal of Glaciology
IS - 220
ER -