Abstract

We combined an ensemble of satellite altimetry, interferometry, and gravimetry data sets using common geographical regions, time intervals, and models of surface mass balance and glacial isostatic adjustment to estimate the mass balance of Earth's polar ice sheets. We find that there is good agreement between different satellite methods--especially in Greenland and West Antarctica--and that combining satellite data sets leads to greater certainty. Between 1992 and 2011, the ice sheets of Greenland, East Antarctica, West Antarctica, and the Antarctic Peninsula changed in mass by -142 ± 49, +14 ± 43, -65 ± 26, and -20 ± 14 gigatonnes year(-1), respectively. Since 1992, the polar ice sheets have contributed, on average, 0.59 ± 0.20 millimeter year(-1) to the rate of global sea-level rise.

Highlights

  • We computed the mass change as determined by satellite radar altimeter (RA) within areas of the EAIS and WAIS that were beyond the scope of the Input-output method (IOM) survey [55] to assess the extent to which the two methods are complementary (Fig. 1). These two areas, which typically fall between glacier drainage basins of the IOM survey, have small imbalances (4.5 T 6.0 and 1.4 T 1.7 Gt year−1, for the EAIS and WAIS respectively), implying that the region surveyed by the IOM is sufficient to capture the vast majority of the present EAIS and WAIS mass imbalance

  • We have quantified and characterized the icesheet imbalance associated with glacier dynamics, surface mass balance (SMB), and a mixture of the two processes

  • We have identified the geographical regions where improved data sets are required; the APIS and the EAIS would benefit from measurements with greater spatial sampling and longer temporal sampling, respectively

Read more

Summary

A Reconciled Estimate of Ice-Sheet

We combined an ensemble of satellite altimetry, interferometry, and gravimetry data sets using common geographical regions, time intervals, and models of surface mass balance and glacial isostatic adjustment to estimate the mass balance of Earth’s polar ice sheets. In Antarctica, the use of GIA models has in practice introduced considerable uncertainty (up to 130 Gt year−1) into ice-sheet mass balance estimates derived from satellite gravimetry [31,32,33]. AIS and GrIS elevation rates were computed by four and two different groups, respectively, using methods that compare surface heights measured along repeated ground tracks This approach provides fine along-track resolution with high precision [54]. Each group made its own decisions on processing the GRACE data, including how to combine results by using different GIA models, handle contamination from external sources, compute uncertainties, and compute regional mass trends and time series. The mass trends contributed by the individual groups agree with the combined GRACE trend to within the estimated uncertainties

Results and Discussion
26 T 36 –85 T 22 –87 T 43 –298 T 58
Conclusions

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.