The modelled surface mass balance of the Antarctic Peninsula at 5.5 km horizontal resolution
This study presents a high-resolution (∼ 5.5 km) estimate of surface mass balance (SMB) over the period 1979–2014 for the Antarctic Peninsula (AP), generated by the regional atmospheric climate model RACMO2.3 and a firn densification model (FDM). RACMO2.3 is used to force the FDM, which calculates...
Main Authors: | , , , , , , , , , , |
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Format: | Article |
Language: | English |
Published: |
Copernicus Publications
2016-02-01
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Series: | The Cryosphere |
Online Access: | http://www.the-cryosphere.net/10/271/2016/tc-10-271-2016.pdf |
Summary: | This study presents a high-resolution (∼ 5.5 km) estimate of surface mass balance (SMB) over the period 1979–2014 for the Antarctic Peninsula
(AP), generated by the regional atmospheric climate model RACMO2.3 and a firn
densification model (FDM). RACMO2.3 is used to force the FDM, which
calculates processes in the snowpack, such as meltwater percolation,
refreezing and runoff. We evaluate model output with 132 in situ SMB
observations and discharge rates from six glacier drainage basins, and find
that the model realistically simulates the strong spatial variability in
precipitation, but that significant biases remain as a result of the highly
complex topography of the AP. It is also clear that the observations
significantly underrepresent the high-accumulation regimes, complicating a
full model evaluation.<br><br>
The SMB map reveals large accumulation gradients, with precipitation values
above 3000 mm we yr<sup>−1</sup> in the western AP (WAP) and below
500 mm we yr<sup>−1</sup> in the eastern AP (EAP), not resolved by coarser
data sets such as ERA-Interim. The average AP ice-sheet-integrated SMB,
including ice shelves (an area of 4.1 × 10<sup>5</sup> km<sup>2</sup>), is
estimated at 351 Gt yr<sup>−1</sup> with an interannual variability of
58 Gt yr<sup>−1</sup>, which is dominated by precipitation (PR)
(365 ± 57 Gt yr<sup>−1</sup>). The WAP (2.4 × 10<sup>5</sup> km<sup>2</sup>)
SMB (276 ± 47 Gt yr<sup>−1</sup>), where PR is large
(276 ± 47 Gt yr<sup>−1</sup>), dominates over the EAP
(1.7 × 10<sup>5</sup> km<sup>2</sup>) SMB (75 ± 11 Gt yr<sup>−1</sup>) and PR
(84 ± 11 Gt yr<sup>−1</sup>). Total sublimation is
11 ± 2 Gt yr<sup>−1</sup> and meltwater runoff into the ocean is
4 ± 4 Gt yr<sup>−1</sup>. There are no significant trends in any of the
modelled AP SMB components, except for snowmelt that shows a significant
decrease over the last 36 years (−0.36 Gt yr<sup>−2</sup>). |
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ISSN: | 1994-0416 1994-0424 |