Accumulation Rate Measurements at Taylor Dome, East Antarctica: Techniques and Strategies for Mass Balance Measurements in Polar Environments

Abstract

1999:Accumulation rate measurements at Taylor Dome, East Antarctica: techniques and strategies for mass balance measurements in polar environments. Geogr. Ann., 81 A (4): 683-694.ABSTRACT. Accumulation rate measurements on the East Antarctic plateau are challenging due to both spatial and temporal variability. Annual stratigraphy is often not reliably or consistently preserved in the firn, and so accumulation cannot be determined from snow pit stratigraphy. We present a suite of accumulation rate measurements collected over several seasons at Taylor Dome, East Antarctica. We compare net accumulation results from direct burial rate measurements and ß-activity firn cores along a 35 km traverse. The two methods are consistent and show that the net accumulation varies from greater than 10 cm a -1 to about 1 cm a -1 (ice equivalent) southwest to northeast across the dome. We map the depth of shallow radar layering to interpolate and extrapolate these point-location measurements and show that considerable variations occur over kilometer scales resulting from subtle surface topography. We also present accumulation rates estimated from concentration of the cosmogenic isotope 10 Be and from activity profiles of 210 Pb. Finally, satellite passive microwave data are used to estimate spatially averaged accumulation rates on the regional to continental scale to provide a context for these local observations. We show that robust mass balance measurements in this environment must rely on spatial and/or temporal averaging.

Wisconsinan and Holocene Climate History from an Ice Core at Taylor Dome, Western Ross Embayment, Antarctica

“…Surface relief (~50 m) is additionally affected by prevailing wind patterns that are concentrated along two primary trajectories: dry southwesterly katabatic winds draining the polar plateau, and southerly cyclonic systems that are the dominant source for snowfall events (Morse et al 1998). Both accumulation and temperature exhibit strong southwest-northeast gradients across the dome, ranging from >9 g cm -2 a -1 to <1 g cm -2 a -1 (Morse et al 1999) and -46°C to -36°C (Waddington and Morse 1994) respectively. Analysis of samples from firn pits shows increasingly enriched stable isotope values and disturbed stratigraphy towards the northeast (Fig.…”

“…These data are complemented by geophysical analyses that provide additional climat-ic information and set the regional context for the ice core climate record. These include spatial measurements of accumulation rate and meteorology (Waddington and Morse 1994; Morse et al 1999), ice penetrating radar detection of internal layers (former ice sheet surfaces) (Morse 1997;Morse et al 1998), and borehole temperature measurements .…”

Extraction of Ice Sheet Layers From Two Intersected Radar Echograms Near Neem Ice Core in Greenland

“…There are many approaches which have been proposed to trace and track internal ice sheet layers from radar echograms. Some of them involve manually digitising layers (Leysinger Vieli, Siegert, and Payne 2004;Morse et al 1999), but it takes a long time for long profile distance. Interactive semi-automated methods improves the efficiency and insure the accuracy of tracking layers (Macgregor et al 2015;Onana et al 2015;Ferro and Bruzzone 2013).…”

“…The ice sheet layers occur where there is a contrast in electromagnetic properties, and reflect variations of ice density, acidity and fabric orientation from the upper to the lower part of the ice sheets (Fujita et al 1999). The isochronous and continuous ice layering is very important to understand how the ice sheets respond to past climate change and to forecast its response to future climate change (Vieli, Siegert, and Payne 2004;Morse et al 1999). On the other hand, the echo-free zone (EFZ) and layer disturbances in the ice sheets are also heated discussed to reflect sub-glacial ice flow at various scales (Drews et al 2009).…”

“…IPRs have been applied to the field of the ice sheet research for more than four decades, and it has wide applications into measurements of surface elevation, ice sheet thickness, snow accumulation rate and bedrock height etc. (Fretwell et al 2013;Bamber et al 2013;Gourmelen et al 2011;Wu et al 2011;Morse et al 1999). In order to achieve penetration depths ranging from hundreds to thousands of metres, IPRs are operated at low frequencies ranging from tens to hundreds of Megahertz and employed on the airborne platforms to avoid being affected by the Earth's ionosphere.…”