Greenland annual accumulation along the EGIG line, 1959–2004, from ASIRAS airborne radar and neutron-probe density measurements
We report annual snow accumulation rates from 1959 to 2004 along a 250 km segment of the Expéditions Glaciologiques Internationales au Groenland (EGIG) line across central Greenland using Airborne SAR/Interferometric Radar Altimeter System (ASIRAS) radar layers and high resolution neutron-probe (NP)...
Main Authors: | , , , , |
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Format: | Article |
Language: | English |
Published: |
Copernicus Publications
2016-08-01
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Series: | The Cryosphere |
Online Access: | http://www.the-cryosphere.net/10/1679/2016/tc-10-1679-2016.pdf |
Summary: | We report annual snow accumulation rates from 1959 to 2004 along
a 250 km segment of the Expéditions Glaciologiques
Internationales au Groenland (EGIG) line across central Greenland
using Airborne SAR/Interferometric Radar Altimeter System (ASIRAS)
radar layers and high resolution neutron-probe (NP) density
profiles. ASIRAS-NP-derived accumulation rates are not statistically different
(95 % confidence interval) from in situ EGIG accumulation measurements from
1985 to 2004. ASIRAS-NP-derived accumulation increases by 20 % below
3000 m elevation, and increases by 13 % above 3000 m elevation
for the period 1995 to 2004 compared to 1985 to 1994. Three Regional Climate
Models (PolarMM5, RACMO2.3, MAR) underestimate snow accumulation
below 3000 m by 16–20 % compared to ASIRAS-NP from
1985 to 2004. We test radar-derived accumulation rates sensitivity to
density using modeled density profiles in place of NP densities.
ASIRAS radar layers combined with Herron and Langway
(1980) model density
profiles (ASIRAS-HL) produce accumulation rates within 3.5 %
of ASIRAS-NP estimates in the dry snow region. We suggest using Herron and Langway (1980) density
profiles to calibrate radar layers detected in dry snow regions of ice
sheets lacking detailed in situ density measurements, such as those
observed by the Operation IceBridge campaign. |
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ISSN: | 1994-0416 1994-0424 |