acceleration
; accuracy assessment
; climate variation
; gravity
; ice sheet
; mass balance
; satellite data
; sea level change
; time series
; Arctic
; Greenland
; Greenland Ice Sheet
; Southern Ocean
英文摘要:
The Greenland and Antarctic ice sheets have been reported to be losing mass at accelerating rates. If sustained, this accelerating mass loss will result in a global mean sea-level rise by the year 2100 that is approximately 43 cm greater than if a linear trend is assumed. However, at present there is no scientific consensus on whether these reported accelerations result from variability inherent to the ice-sheet-climate system, or reflect long-term changes and thus permit extrapolation to the future. Here we compare mass loss trends and accelerations in satellite data collected between January 2003 and September 2012 from the Gravity Recovery and Climate Experiment to long-term mass balance time series from a regional surface mass balance model forced by re-analysis data. We find that the record length of spaceborne gravity observations is too short at present to meaningfully separate long-term accelerations from short-term ice sheet variability. We also find that the detection threshold of mass loss acceleration depends on record length: to detect an acceleration at an accuracy within ±10 Gt yr -2, a period of 10 years or more of observations is required for Antarctica and about 20 years for Greenland. Therefore, climate variability adds uncertainty to extrapolations of future mass loss and sea-level rise, underscoring the need for continuous long-term satellite monitoring.
Bristol Glaciology Centre, School of Geographical Science, Bristol BS8 1SS, United Kingdom; Department of Physics, University of Colorado at Boulder, Boulder, CO 80309, United States; Institute for Marine and Atmospheric Research, Utrecht University, 3508 TA Utrecht, Netherlands; Deutsches GeoForschungsZentrum GFZ, 14473 Potsdam, Germany
Recommended Citation:
Wouters B.,Bamber J.L.,Van Den Broeke M.R.,et al. Limits in detecting acceleration of ice sheet mass loss due to climate variability[J]. Nature Geoscience,2013-01-01,6(8)