Greenland high-elevation mass balance: inference and implication of reference period (1961-90) imbalance

William Colgan, Jason E. Box, Morten L. Andersen, Xavier Fettweis, Beáta Csathó, Robert S. Fausto, Dirk van As, John Wahr

Publikation: Bidrag til tidsskriftArtikelForskningpeer review

20 Citationer (Scopus)

Abstrakt

We revisit the input-output mass budget of the high-elevation region of the Greenland ice sheet evaluated by the Program for Arctic Regional Climate Assessment (PARCA). Our revised reference period (1961-90) mass balance of 54±48 Gt a-1 is substantially greater than the 0±21 Gt a-1 assessed by PARCA, but consistent with a recent, fully independent, input-output estimate of high-elevation mass balance (41±61 Gt a-1). Together these estimates infer a reference period high-elevation specific mass balance of 4.8±5.4 cm w.e. a-1. The probability density function (PDF) associated with this combined input-output estimate infers an 81% likelihood of high-elevation specific mass balance being positive (>0 cm w.e. a-1) during the reference period, and a 70% likelihood that specific balance was >2 cm w.e. a-1. Given that reference period accumulation is characteristic of centurial and millennial means, and that in situ mass-balance observations exhibit a dependence on surface slope rather than surface mass balance, we suggest that millennial-scale ice dynamics are the primary driver of subtle reference period high-elevation mass gain. Failure to acknowledge subtle reference period dynamic mass gain can result in underestimating recent dynamic mass loss by ∼17%, and recent total Greenland mass loss by ∼7%.

OriginalsprogEngelsk
Sider (fra-til)105-117
Antal sider13
TidsskriftAnnals of Glaciology
Vol/bind56
Udgave nummer70
DOI
StatusUdgivet - 2015

Programområde

  • Programområde 5: Natur og klima

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