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Quantifying the seasonal “breathing” of the Antarctic ice sheet
Author(s) -
Ligtenberg S. R. M.,
Horwath M.,
den Broeke M. R.,
Legrésy B.
Publication year - 2012
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 - 10.1029/2012gl053628
Subject(s) - firn , elevation (ballistics) , geology , ice sheet , climatology , greenland ice sheet , atmospheric sciences , annual cycle , antarctic ice sheet , groenlandia , environmental science , cryosphere , snow , sea ice , oceanography , geomorphology , geometry , mathematics
One way to estimate the mass balance of an ice sheet is to convert satellite observed surface elevation changes into mass changes. In order to do so, elevation and mass changes due to firn processes must be taken into account. Here, we use a firn densification model to simulate seasonal variations in depth and mass of the Antarctic firn layer, and assess their influence on surface elevation. Forced by the seasonal cycle in temperature and accumulation, a clear seasonal cycle in average firn depth of the Antarctic ice sheet (AIS) is found with an amplitude of 0.026 m, representing a volume oscillation of 340 km 3 . The phase of this oscillation is rather constant across the AIS: the ice sheet volume increases in austral autumn, winter and spring and quickly decreases in austral summer. Seasonal accumulation differences are the major driver of this annual ‘breathing’, with temperature fluctuations playing a secondary role. The modeled seasonal elevation signal explains ∼31% of the seasonal elevation signal derived from ENVISAT radar altimetry, with both signals having similar phase.