Sea Ice Mass Balances influenced by Ice Shelves (SIMBIS)
Final Report Abstract
In this work, we successfully implemented a monitoring concept of sea-ice and snow properties in an ice-shelf influenced fast-ice regime in the eastern Weddell Sea. Such activities are challenging and therefore rare in the harsh environment of Antarctica. The data collected in this newly-established long-term sea-ice observatory represent a status quo, since signs of global warming are still not observed in this region, and are expected to grow in value the longer the time series is maintained. Our results suggest that ice-shelf processes govern fast-ice properties and their evolution in the eastern Weddell Sea, contributing more than half of the annual sea-ice volume. When monitored consistently, fast-ice properties may even reflect the strength of ocean/ice-shelf interaction in the otherwise inaccessible cavity, and serve as a proxy for basal melting. The shown impact of snow properties on X-band SAR backscatter during the transition of austral winter to austral spring is of high value, as comparable investigations around Antarctica were previously focussed on studies with C-band SAR, featuring different interactions with sea-ice snow cover. These results create a manifold of possibilities to base future research on. Additional measurements, e.g., of snow salinity and (quantitative) snow liquid-water content, would be of great interest in future studies, as well as a combination with physical backscatter models or snow/sea-ice models might be informative in future studies and but could also further increase the potential of this data set. Results in volume ice production, polynya area as well as thin-ice frequency distribution from MODIS thermal-infrared satellite imagery along the Weddell Sea coast suggest that the neglect of certain regions in other studies drastically underestimates the total average polynya area and ice production. Hence, these regions should be further investigated by upcoming studies as they also contribute to the deep-water formation. Also the ability of MODIS for investigating and monitoring Antarctic fast-ice areas was highlighted. In addition to the new process knowledge, this project also provided the first steps towards a variety of new methods with great scientific applicability such as the determination of plateletlayer properties and evolution over larger temporal and spatial scales. Furthermore, the possibility to conduct long-term monitoring of polynyas from thermal-infrared imagery was improved and the resulting data set is expected to be of benefit to the scientific comunity.
Publications
- (2015). Towards an estimation of sub-sea-ice platelet-layer volume with multi-frequency electromagnetic induction sounding. Annals of Glaciology, 56(69), 137-146
Hunkeler, P., S. Hendricks, M. Hoppmann, S. Paul, and R. Gerdes
(See online at https://doi.org/10.3189/2015AoG69A705) - (2015): Ice platelets below Weddell Sea landfast sea ice. Annals of Glaciology 56(59), 175-190
Hoppmann, M., Nicolaus, M., Paul, S., Hunkeler, P., Heinemann, G., Willmes, S., Timmermann, R., Boebel, O., Schmidt, T., Kühnel, M., König-Langlo, G., Gerdes, R.
(See online at https://doi.org/10.3189/2015AoG69A678) - (2015): Long-term coastal-polynya dynamics in the Southern Weddell Sea from MODIS thermal-infrared imagery. The Cryosphere, 9, 2027-2041
Paul, S., Willmes, S., Heinemann, G.
(See online at https://doi.org/10.5194/tc-9-2027-2015) - (2015): Spatial Feature Reconstruction of cloud-covered areas in daily MODIS composites. Remote sensing 7(5), 5042-5056
Paul, S., Willmes, S., Gutjahr, O., Preußer, A., Heinemann, G.
(See online at https://doi.org/10.3390/rs70505042) - (2015): The impact of early summer snow properties on Antarctic landfast sea-ice X-band backscatter. Annals of Glaciology 56(59), 263-273
Paul, S., Willmes, S., Hoppmann, M., Hunkeler, P., Heinemann, G., Nicolaus, M.
(See online at https://doi.org/10.3189/2015AoG69A715) - Seasonal evolution of an ice-shelf influenced fast-ice regime, derived from an autonomous thermistor chain (2015). Journal of Geophysical Research: Oceans 120, 1703-1724
Hoppmann, M., M. Nicolaus, P. A. Hunkeler, P. Heil, L.-K. Behrens, G. König- Langlo, R. Gerdes
(See online at https://doi.org/10.1002/2014JC010327) - (2016), A glimpse beneath Antarctic sea ice: Platelet layer volume from multifrequency electromagnetic induction sounding, Geophys. Res. Lett., 43, 222–231
Hunkeler, P. A., M. Hoppmann, S. Hendricks, T. Kalscheuer, and R. Gerdes
(See online at https://doi.org/10.1002/2015GL065074)
