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Ice streaming in the Laurentide Ice Sheet: A first comparison between data‐calibrated numerical model output and geological evidence
Author(s) -
Stokes Chris R.,
Tarasov Lev
Publication year - 2010
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2009gl040990
Subject(s) - ice sheet , deglaciation , ice sheet model , geology , ice stream , streams , ice divide , cryosphere , climatology , glacial period , sea ice , oceanography , geomorphology , computer science , computer network
Despite the importance of rapidly‐flowing ice streams to ice sheet mass balance, their incorporation into numerical ice sheet models is a major scientific challenge. This introduces large uncertainties in model output and inhibits a more complete understanding of the role of ice streams in overall ice sheet stability. Recent computational advances have enabled more realistic representations of ice streaming but few studies have attempted to compare model output against known locations of ice streams. This paper compares predictions of ice streaming derived from a large ensemble analysis of a Glacial Systems Model of the Laurentide Ice Sheet against independent geological evidence compiled from previously published studies. Although the precise dating of paleo‐ice stream locations is problematic, our analysis includes comparisons at six different time‐steps (18 to 10 cal ka BP) during deglaciation. Results indicate that the model is successful in predicting all of the major marine‐terminating ice streams but there is mixed success in simulating terrestrial ice streams in the right place and at the right time, which is vital in guiding future model development. The model also reveals that whilst some ice streams persist throughout deglaciation the focus of mass loss associated with ice streaming switches through time with dynamic changes in ice stream catchments and tributaries. This implies that major changes in ice stream activity are to be expected in a deglaciating ice sheet, with important implications for contemporary ice sheet dynamics.