Coastal ice-core record of recent northwest Greenland temperature and sea-ice concentration

Osterberg, E. C.; Hawley, R. L.; Wong, G. J.; Kopec, B. G.; Ferris, D. G.; Howley, Jennifer A.

doi:10.3189/2015jog15j054

Cited by 21 publications

(25 citation statements)

References 67 publications

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“…We determined depth-age curves by identifying annual layers based on robust seasonal oscillations in δ 18 O and the concentrations of major ions, methanesulphonic acid, and dust, consistent with previous ice core studies ( Figure S1; Mosley-Thompson et al, 2001;Osterberg et al, 2015). We combined the depth-age curves with core density to calculate annual accumulation rates.…”

Section: Methodsmentioning

confidence: 90%

Ice Core Records of West Greenland Melt and Climate Forcing

Graeter

Osterberg

Ferris

et al. 2018

Geophysical Research Letters

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Remote sensing observations and climate models indicate that the Greenland Ice Sheet (GrIS) has been losing mass since the late 1990s, mostly due to enhanced surface melting from rising summer temperatures. However, in situ observational records of GrIS melt rates over recent decades are rare. Here we develop a record of frozen meltwater in the west GrIS percolation zone preserved in seven firn cores. Quantifying ice layer distribution as a melt feature percentage (MFP), we find significant increases in MFP in the southernmost five cores over the past 50 years to unprecedented modern levels (since 1550 CE). Annual to decadal changes in summer temperatures and MFP are closely tied to changes in Greenland summer blocking activity and North Atlantic sea surface temperatures since 1870. However, summer warming of ~1.2°C since 1870–1900, in addition to warming attributable to recent sea surface temperature and blocking variability, is a critical driver of high modern MFP levels.

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Section: Methodsmentioning

confidence: 90%

Ice Core Records of West Greenland Melt and Climate Forcing

Graeter

Osterberg

Ferris

et al. 2018

Geophysical Research Letters

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“…2 for locations). Mernild et al (2014) also find a significant influence of the NAO on their composite coastal Greenland precipitation record, and both Wong et al (2015) and Osterberg et al (2015) find significant negative correlations between the NAO and precipitation and temperature, respectively, at Thule in northwest Greenland. The EOF2 loading is also weak in the region of Summit (Fig.…”

Section: Icebridge Accumulation Temporal Trendsmentioning

confidence: 94%

Regional Greenland accumulation variability from Operation IceBridge airborne accumulation radar

et al. 2017

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Abstract. The mass balance of the Greenland Ice Sheet (GrIS) in a warming climate is of critical interest to scientists and the general public in the context of future sea-level rise. An improved understanding of temporal and spatial variability of snow accumulation will reduce uncertainties in GrIS mass balance models and improve projections of Greenland's contribution to sea-level rise, currently estimated at 0.089 ± 0.03 m by 2100. Here we analyze 25 NASA Operation IceBridge accumulation radar flights totaling >  17 700 km from 2013 to 2014 to determine snow accumulation in the GrIS dry snow and percolation zones over the past 100–300 years. IceBridge accumulation rates are calculated and used to validate accumulation rates from three regional climate models. Averaged over all 25 flights, the RMS difference between the models and IceBridge accumulation is between 0.023 ± 0.019 and 0.043 ± 0.029 m w.e. a−1, although each model shows significantly larger differences from IceBridge accumulation on a regional basis. In the southeast region, for example, the Modèle Atmosphérique Régional (MARv3.5.2) overestimates by an average of 20.89 ± 6.75 % across the drainage basin. Our results indicate that these regional differences between model and IceBridge accumulation are large enough to significantly alter GrIS surface mass balance estimates. Empirical orthogonal function analysis suggests that the first two principal components account for 33 and 19 % of the variance, and correlate with the Atlantic Multidecadal Oscillation (AMO) and wintertime North Atlantic Oscillation (NAO), respectively. Regions that disagree strongest with climate models are those in which we have the fewest IceBridge data points, requiring additional in situ measurements to verify model uncertainties.

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“…IceBridge accumulation results at EGIG T-31 (seeFig. 2for location) from 1957 to 2014 are statistically indistinguishable from Airborne SAR/Interferometric Radar Altimeter System (ASIRAS) accumulationOverly et al, 2016) and field measurements (H.Fischer, personal communication, 2015). Error bars are 1 standard deviation of ASIRAS accumulation over data points from that time period.…”

mentioning

confidence: 83%

“…Error bars are 1 standard deviation of ASIRAS accumulation over data points from that time period. location from the Airborne SAR/Interferometric Radar Altimeter System (ASIRAS;Overly et al, 2016; see…”

mentioning

confidence: 99%

Response to Reviewer #1

Lewis¹

2017

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The mass balance of the Greenland Ice Sheet (GrIS) in a warming climate is of critical interest to scientists and the general public in the context of future sealevel rise. An improved understanding of temporal and spatial variability of snow accumulation will reduce uncertainties in GrIS mass balance models and improve projections of Greenland's contribution to sea-level rise, currently estimated at 0.089 ± 0.03 m by 2100. Here we analyze 25 NASA Operation IceBridge accumulation radar flights totaling > 17 700 km from 2013 to 2014 to determine snow accumulation in the GrIS dry snow and percolation zones over the past 100-300 years. IceBridge accumulation rates are calculated and used to validate accumulation rates from three regional climate models. Averaged over all 25 flights, the RMS difference between the models and IceBridge accumulation is between 0.023 ± 0.019 and 0.043 ± 0.029 m w.e. a −1 , although each model shows significantly larger differences from IceBridge accumulation on a regional basis. In the southeast region, for example, the Modèle Atmosphérique Régional (MARv3.5.2) overestimates by an average of 20.89 ± 6.75 % across the drainage basin. Our results indicate that these regional differences between model and IceBridge accumulation are large enough to significantly alter GrIS surface mass balance estimates. Empirical orthogonal function analysis suggests that the first two principal components account for 33 and 19 % of the variance, and correlate with the Atlantic Multidecadal Oscillation (AMO) and wintertime North Atlantic Oscillation (NAO), respectively. Regions that disagree strongest with climate models are those in which we have the fewest IceBridge data points, requiring additional in situ measurements to verify model uncertainties.

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Coastal ice-core record of recent northwest Greenland temperature and sea-ice concentration

Cited by 21 publications

References 67 publications

Ice Core Records of West Greenland Melt and Climate Forcing

Ice Core Records of West Greenland Melt and Climate Forcing

Regional Greenland accumulation variability from Operation IceBridge airborne accumulation radar

Response to Reviewer #1

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