Improved geodetic glacier mass balance measurements by integrating remote sensing, surface mass balance and firn compaction modelling - a case study from James Ross Island, Antarctica

点击翻译按钮获取中文摘要

The project targets on the improvement of geodetic glacier mass balances. Besides of an improvement of the absolute precision we aim at a general improvement of the error quantification and error estimation. In a first setp elevation and volume changes will be computed by differencing digital elevation models (DEMs) from different dates and sources. The DEMs will be generated by photogrammetry or SAR interferometry (especially using data of the German TanDEM-X mission). The current limitations of the geodetic method result from the unquantified penetration depth of the radar signal into dry snow or a frozen snow cover as well as from the conversion of volume to mass by assuming a fixed density or specific density profile. We propose to improve the conversions by coupling a glacier surface mass balance and firn compaction model with the remote sensing results. In order to initialise and validate the model we will rely on field surveys as well as a profound database of the applicant as well as the Czech and Argentine counterparts. We will quantify the effects of x-band radar penetration depth by comparing summer and winter situations as well as comparison to in-situ GNSS measurements. In addition, we will compare the results of the geodetic method with the Input-Output (or flux gate) approach. The project is carried out in close collaboration of Czech partners from Brno and Prague University as well as our counterparts from the Instituto Antártico Argentino. We propose James Ross Island - located at the northeaster tip of the Antarctic Peninsula - as study site. Despite of its location in Antarctica, we primarily aim at methodological developments that can be transferred to other regions and locations. The proposed study site is favourable due to its database and the joint preparatory work as well as the international collaboration and logistic access almost ideal conditions for the proposed work that does not lead to significant additional costs in comparison to locations with comparable glacier sizes. Specifically, the preparatory work shows that the observed elevation changes are quite heterogeneous on the different glaciers enabling the analysis of changes in different magnitudes, directions and underlying mechanisms within a very narrow area in addition to different meteorological conditions. This situation is very specific to the proposed site and provides ideal conditions for method development.