Remote Sensing of Sea Ice on the MOSAiC Ice Floe

Abstract:

The one-year long MOSAiC (Multidisciplinary drifting Observatory for the Study of Arctic Climate) drift expedition presents an excellent opportunity to evaluate current satellite remote sensing observations and develop new remote sensing methods. While the research icebreaker Polarstern is drifting with the sea ice from October 2019 to September 2020 several remote sensing instruments designed for observing the sea ice and snow on top were installed on the ice floe next to Polarstern and on the vessel itself. This, for the first time, will allow to monitoring the freeze-up to melt onset cycle and different ice types. Most of the instruments have counterparts in space, and their measurements are designed to obtain a better process understanding of the interaction of electromagnetic waves with snow and sea ice. Satellite measurements constitute a few of the most important climate data records for polar regions. The MOSAiC experiments will help to improve them and better assess their uncertainties. In particular the following measurements were performed during MOSAiC: (i) microwave radiometer observations at 0.5–2, 1.4, 7, 11, 19, 37, and 89 GHz frequencies in dual polarization, (ii) fully-polarimetric, microwave radar scatterometer observations at L-, C-, X-, Ku-, and Ka-band frequencies, (iii) reflected GNSS measurements from snow and ice, and (iv) infrared, visual, and hyperspectral cameras. The instruments on the ice floe were oriented to observe similar snow and ice conditions. The remote sensing measurements were accompanied by extensive measurements of snow and ice properties in the vicinity of the measurement field. By having these coincident multi-frequency remote sensing and in-situ observations as well as the environmental conditions measured by other MOSAiC teams, factors influencing the emission, reflection, and scattering of microwaves in sea ice and snow can be better understood so that new remote sensing methods can be developed and contribute to new satellite missions. Here we will present an overview of the measurement program and first results from simultaneously measuring instruments.