Thermal-optical analysis of light-absorbing snow impurities

Abstract

Thermal-optical analysis of light-absorbing snow impurities

Daniela Kaua, Andjela Vukićevića, Jakub Bieleckia, Michaela Zuckerhuta, Marion Greilingerb, and Anne Kasper-Giebla

aInstitute of Chemical Technologies and Analytics, TU Wien, 1060 Vienna, Austria bDepartment Climate-Impact-Research, GeoSphere Austria, 1190 Vienna, Austria

Glacial retreat is globally observed with concern. The occurrence of light-absorbing snow impurities, e.g. elemental carbon and mineral dust, lead to an earlier melt of the snow cover and earlier exposure of the glacial ice. The determination of both compounds, elemental carbon and mineral dust, is of special interest in high alpine regions. However, their co-occurrence leads to a bias in the determination of elemental carbon via thermal-optical analysis or even erroneously suggests that no elemental carbon is present in the sample [1]. We analyzed snow samples collected on glaciers surrounding the Global Atmosphere Watch station Sonnblick Observatory. In the snowpacks sampled in 2021 and 2022, 10 and 38% of samples, respectively, showed signs of biased elemental carbon concentrations. We discuss the necessary correction of the analysis data. Until now, mineral dust concentrations are only accessible using an additional analytical method. We present an approximation utilizing the interferences introduced into thermal-optical analysis by mineral dust.

____ [1] Kau, D., Greilinger, M., Kirchsteiger, B., Göndör, A., Herzig, C., Limbeck, A., Eitenberger, E., and Kasper-Giebl, A. (2022) Atmos. Meas. Tech. 15, 5207-5217.