Variability of the recent accumulation rate in coastal Dronning Maud Land, Antarctica

• Main Author: Anschütz, Helgard
• Other Authors: Miller, Heinrich, Villinger, Heinrich
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: Universität Bremen 2007
• Subjects: Antarctica; accumulation rates; glaciology; small-scale variability; 550; 550 Earth sciences and geology; ddc:550; East Antarctica; Dronning Maud Land; Polar Plateau; Antarc*; Antarktis*
• Online Access: https://media.suub.uni-bremen.de/handle/elib/2350; https://nbn-resolving.org/urn:nbn:de:gbv:46-diss000106674

In light of possible future sea-level change, investigation of surface-mass balance of the polar ice sheets has become amajor concern of glaciological research. Yet Antarctica's total surface-mass balance is still not accurately determined, making up for the largest uncertainties of predictions regarding sea-level rise in the 21st century.This study contributes new data sets of recent snow-accumulation rates and provides insight in local features affecting the small-scale distribution of accumulation.The aim of the work is to establish a detailed picture of spatial accumulation variability on the scale of some tens of kilometers and of temporal behaviour on interannual to decadal scales. To this end, high-frequency ground-penetrating radar profiling and analyses of shallow firn cores have been utilized. The area of investigation focuses on coastal regions of Dronning Maud Land, East Antarctica, which are likewise in the focus of new satellite missions. The coastal regions are susceptible to global climate change but the local to regional-scale variability of accumulation is not well addressed by general circulationmodels or regional climate models, thus making it necessary to obtain and analyze field data.The accumulation rates on Potsdam Glacier in the coastal part of central Dronning Maud Land have been found to show an undulating pattern, exhibiting a one-fold standard deviation of nearly 50 % around a mean value of some140 kg m-2a-1 for the time period 1970-2004. Temporal variations on decadal scales obtained from the area-wide mean values are only a few per cent, but inter-annual variations derived from dated firn cores are high, showing values between 30-40 % of the core means. Statistical analysis of spatial accumulation series reveals a high periodicity of these undulations with a wavelength of 5~km and amplitudes of 10 m, leading to the conclusion that the features are similar to the megadunes known from the polar plateau, although they lack the spatial extent and the extreme snow morphology of the ...