Greenland Ice Sheet: High-Elevation Balance and Peripheral Thinning

Krabill, William B.; Abdalati, W.; Frederick, E.; Manizade, S.; Martin, C. F.; Sonntag, J. G.; Swift, Robert N.; Thomas, Robert H.; Wright, Wayne; Yungel, James K.

doi:10.1126/science.289.5478.428

Cited by 385 publications

(324 citation statements)

References 8 publications

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“…Regional climate models, supported by in situ observations, suggest that both accumulation and melting have increased during the past decade, with melting increasing faster than accumulation 5 . These surface mass balance estimates are consistent with radar altimeter measurements during 1992-2003 that show interior growth 6,7 , and with laser altimeter observations that show thinning in the 1990s at low elevations 8 where increased melting is probably more important than increased accumulation. Laser altimeter and satellite radar imaging observations over the last decade have shown accelerated glacial mass loss at the ice sheet margins 2-4,9,10 .…”

Section: Acceleration Of Greenland Ice Mass Loss In Spring 2004supporting

confidence: 86%

Acceleration of Greenland ice mass loss in spring 2004

Velicogna

Wahr

2006

Nature

345

246

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Section: Acceleration Of Greenland Ice Mass Loss In Spring 2004supporting

confidence: 86%

Acceleration of Greenland ice mass loss in spring 2004

Velicogna

Wahr

2006

Nature

345

246

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“…Meanwhile, there are reports of an increase in the surface elevation at higher altitudes since 1990 (Krabill et al, 2000;Nghiem et al, 2005;Hanna et al, 2006), supporting calibrated climate models which show that some regions of the ice sheet have experienced higher than average accumulation rates, especially in the south (Burgess et al, 2010). A recent modelling study found larger than average accumulation rates across the GrIS between 1958 and 2007, and that the surface mass balance over the same period is between 32-63% higher than previous estimates (Ettema et al, 2009).…”

Section: Introductionmentioning

confidence: 58%

Spatially extensive estimates of annual accumulation in the dry snow zone of the Greenland Ice Sheet determined from radar altimetry

et al. 2010

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Abstract. We present estimates of accumulation rate along a 200 km transect ranging in elevation from 2750 to 3150 m in the dry snow zone on the western slope of the Greenland Ice Sheet. An airborne radar altimeter is used to estimate the thickness of annual internal layers and, in conjunction with ground based snow/firn density profiles, annual accumulation rates between 1998 and 2003 are derived. A clear gradient in the thickness of each layer observed by the radar altimeter and in the associated estimates of annual accumulation is seen along the transect, with a 33.6%± 16% mean decrease in accumulation from west to east. The observed inter-annual variability is high, with the annual mean accumulation rate estimated at 0.359 m.w.e. yr −1 (s.d. ± 0.049 m.w.e. yr −1 ). Mean accumulation rates modelled using meteorological models overestimate our results by 16% on average, but by 32% and 42% in the years 2001 and 2002. The methodology presented here demonstrates the potential to obtain accurate and spatially extensive accumulation rates from radar altimeters in regions of ice sheets where field observations are sparse, and accumulation rates greater than several tens of cm.

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“…Ice-surface elevation profiles over WJ were acquired with NASA's Airborne Topographic Mapper (ATM) in the springs of 1996 and 2002 [Bamber et al, 2005]. The technical details of the ATM are described elsewhere [Krabill et al, 2000]; vertical accuracies are estimated to be 0.1 m or better [Bamber et al, 2005].…”

Section: Methodsmentioning

confidence: 99%

Acceleration in thinning rate on western Svalbard glaciers

Kohler¹,

James²,

Murray³

et al. 2007

Geophysical Research Letters

189

204

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Geodetic measurements indicate that a number of glaciers in western Svalbard ranging in size from 5–1000 km2 are losing mass at an accelerating rate. The average thinning rate for Midtre Lovénbreen, the glacier with the best data coverage, has increased steadily since 1936. Thinning rates for 2003–2005 are more than 4 times the average for the first measurement period 1936–1962 and are significantly greater than presented previously. On Slakbreen, thinning rates for the latest measurement period 1990–2003 are more than 4 times that of the period 1961–1977. Thinning of several glaciers along a previously measured airborne lidar profile in Wedel Jarls Land has also increased, doubling between the period 1990–1996 and 1996–2002. Our results imply an increased sea level contribution from Svalbard. In addition, the mass loss is an important influence on measured rates of rebound on western Svalbard and should be factored into analysis of GRACE results.

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Greenland Ice Sheet: High-Elevation Balance and Peripheral Thinning

Cited by 385 publications

References 8 publications

Acceleration of Greenland ice mass loss in spring 2004

Acceleration of Greenland ice mass loss in spring 2004

Spatially extensive estimates of annual accumulation in the dry snow zone of the Greenland Ice Sheet determined from radar altimetry

Acceleration in thinning rate on western Svalbard glaciers

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