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Recent regional cooling has impacted the natural systems of the Antarctic Peninsula (AP); however, little is known concerning the changes in the high parts of the glacial systems. Dry-snow line (DSL), situated in the high parts of glaciers, is the uppermost limit of frequent or occasional surface melt. We analyse dry-snow line altitude (DSLA) changes on the AP during 2004–2020 using C-band synthetic aperture radar time series data. We demonstrate that the DSLA in the eastern part of the AP is usually higher than that of the western part. Moreover, using simulated climatic variables from regional climate models, the lowering in altitude of DSL of glaciers in most areas is identified as a response to a decrease in snowmelt and an increase in precipitation. Furthermore, correlation analyses between simulated climatic variables and the DSLA are conducted. These results present the sensitive response of variations in DSLA to meteorological conditions, and the capability of DSLA being a proxy of polar local climate in high-altitude areas with no in situ meteorological observations. [ABSTRACT FROM AUTHOR]

Mass changes of the Antarctic ice sheet impact sea-level rise as climate changes, but recent rates have been uncertain. Ice, Cloud and land Elevation Satellite (ICESat) data (2003-08) show mass gains from snow accumulation exceeded discharge losses by 82±25 Gt a-1, reducing global sea-level rise by 0.23mma-1. European Remote-sensing Satellite (ERS) data (1992-2001) give a similar gain of 112±61 Gt a-1. Gains of 136 Gt a-1 in East Antarctica (EA) and 72 Gt a-1 in four drainage systems (WA2) in West Antarctic (WA) exceed losses of 97 Gt a-1 from three coastal drainage systems (WA1) and 29 Gt a-1 from the Antarctic Peninsula (AP). EA dynamic thickening of 147 Gt a-1 is a continuing response to increased accumulation (>50%) since the early Holocene. Recent accumulation loss of 11 Gt a-1 in EA indicates thickening is not from contemporaneous snowfall increases. Similarly, the WA2 gain is mainly (60 Gt a-1) dynamic thickening. In WA1 and the AP, increased losses of 66±16 Gt a-1 from increased dynamic thinning from accelerating glaciers are 50% offset by greater WA snowfall. The decadal increase in dynamic thinning in WA1 and the AP is approximately one-third of the long-term dynamic thickening in EA and WA2, which should buffer additional dynamic thinning for decades. [ABSTRACT FROM AUTHOR]

Coastal ice cores provide an opportunity to investigate regional climate and sea-ice variability in the past to complement hemispheric-scale climate reconstructions from ice-sheet-interior ice cores. Here we describe robust proxies of Baffin Bay temperature and sea-ice concentration from the coastal 2Barrel ice core collected in the Thule region of northwest Greenland. Over the 1990-2010 record, 2Barrel annually averaged methanesulfonic acid (MSA) concentrations are significantly correlated with May-June Baffin Bay sea-ice concentrations and summer temperatures. Higher MSA is observed during warmer years with less sea ice, indicative of enhanced primary productivity in Baffin Bay. Similarly, 2Barrel annually averaged deuterium excess (d-excess) values are significantly correlated with annual Baffin Bay sea-ice concentrations and summer and annual temperatures. Warm (cool) years with anomalously low (high) sea-ice concentration are associated with proportionally more (less) low-d-excess Baffin Bay moisture at the ice-core site. Multilinear regression models incorporating 2Barrel MSA, d-excess and snow accumulation account for 38-51% of the Baffin Bay sea-ice and temperature variance. The annual temperature model is significantly correlated with temperatures throughout most of Greenland and eastern Arctic Canada due to the strong influence of the North Atlantic Oscillation and Atlantic Multidecadal Oscillation. [ABSTRACT FROM AUTHOR]

To assess the role of methodological differences on measured trace-element concentrations in ice cores, we developed an experiment to test the effects of acidification strength and time on dust dissolution using snow samples collected in West Antarctica and Alaska. We leached Antarctic samples for 3 months at room temperature using nitric acid at concentrations of 0.1, 1.0 and 10.0% (v/v). At selected intervals (20 min, 24 hours, 5 days, 14 days, 28 days, 56 days, 91 days) we analyzed 23 trace elements using inductively coupled plasma mass spectrometry. Concentrations of lithogenic elements scaled with acid strength and increased by 100-1380% in 3 months. Incongruent elemental dissolution caused significant variability in calculated crustal enrichment factors through time (factor of 1.3 (Pb) to 8.0 (Cs)). Using snow samples collected in Alaska and acidified at 1% (v/v) for 383 days, we found that the increase in lithogenic element concentration with time depends strongly on initial concentration, and varies by element (e.g. Fe linear regression slope = 1.66; r = 0.98). Our results demonstrate that relative trace-element concentrations measured in ice cores depend on the acidification method used. [ABSTRACT FROM AUTHOR]

Commercial cone penetration testing (CPT) equipment was adapted to allow penetrative testing in hard polar firn to depths of 10 m. The apparatus is hydraulically driven, rate-controllable and able to penetrate firn with a resistance of 10MPa. It can be mounted on many types of typical polar vehicles, requiring connection to only hydraulics and 12V electricity. Data recorded include both cone tip resistance and sleeve friction, a parameter not previously examined through such testing. This paper describes the development and calibration of the equipment and examines factors including snow density, penetration rate and cone size and shape that are shown to affect CPT interpretation. CPT can be used efficiently in polar environments to potentially provide estimates of physical parameters in hard firn to substantial depth. [ABSTRACT FROM AUTHOR]