Arctic iceberg

Support to Microwave Scatterometer measurements during MOSAiC

Arctic iceberg
Arctic iceberg

This project provides valuable Fiducial Reference Measurements from the Arctic region for the validation of several EUMETSAT, EU Copernicus and ESA missions.

Last Updated

14 November 2020

Published on

10 March 2020

Support to Microwave Scatterometer Measurements During MOSAiC map
Figure 1: Potential movement of the observatory

Multi-frequency scatterometer measurements are being collected during the MOSAiC (Multidisciplinary drifting Observatory for the Study of Arctic Climate) campaign in the Central Arctic from October 2019 to October 2020.

The MOSAiC campaign offers an unprecedented opportunity to obtain fiducial reference measurements of snow and sea ice properties over a complete annual cycle required for the development and validation of satellite-based retrieval algorithms, as well as the improvement of microwave radiative transfer models.

Such an extensive dataset has not been available to date, and will contribute towards the validation of several EUMETSAT, EU Copernicus and ESA missions. Figure 1 shows the potential movement of the observatory (RV Polarstern icebreaker) along the Transpolar Drift during the course of the expedition.

Remote sensing instruments in the Central Observatory

Instrument Details PI Institution Leg 1 responsible
Ku/Ka radar Dual-frequency scanning radar: 12-18 GHz (Ku) and 3040 GHz J. Stroeve University of Manitoba S. Hendricks
L-band Scatterometer 1.26 GHz scanning radar R. Scharien University of Victoria G. Spreen
C-band Scatterometer C-band (~5 GHz) scanning radar J. Yackel University of Calgary G. Spreen
X-band Scatterometer 9.6 GHz scanning radar C. Duguay University of Waterloo G. Spreen
MW Radiometer UWBRAD Ultra-wideband 0.5-2 GHz radiometer (P to L-band) J. Johnson Ohio State University O. Demir
MW Radiometer ELBARA 1.4 GHz (L-band) M. Schwank
T. Casal
WSL/ESA G. Spreen
MW Radiometer 19-37-89-GHz 19, 37, 89 GHz (K, Ka, W-band) J. Stroeve University of Manitoba G. Spreen
MW Radiometer ARIEL 1.4 GHz (L-band) C. Cabarro ICM-CSIC G. Spreen
GNSS-R Reflected GNSS signals from snow/ice E. Cardellach
T. Casal
G. Spreen
Infrared Camera Surface temperature G. Spreen University of Bremen G. Spreen
Video Camera Visual overview of RS site G. Spreen University of Bremen G. Spreen
Ku/Ka radar Dual-frequency scanning radar: 12-18 GHz (Ku) and 3040 GHz J. Stroeve University of Manitoba S. Hendricks


The scatterometer measurements are being acquired to investigate the temporal evolution of signals caused by environmental changes such as:

  • snow accumulation and metamorphism;
  • temperature changes;
  • ice growth and melting;
  • desalination;
  • ice crusts and wind-packed snow formation.

These environmental changes are effective on a satellite footprint scale, which will allow comparison to the temporal evolution of the ground-based and satellite scatterometer/radar measurements.

Improved forward models of the radiative transfer in the snow and sea ice are needed to better understand the electromagnetic interaction with snow and sea-ice, and, thus, the signal measured by radar satellites, and to develop retrieval methods of snow and ice properties from these measurements.

As a fundamental prerequisite to develop and validate such models, joint ground-based scatterometer measurements, with coincident in-situ measurements of all relevant variables, are being acquired. MOSAiC offers the opportunity to perform such joint measurements under different environmental conditions, starting with the ice freeze-up and first snow accumulation throughout the winter until spring and summer, when the snow and sea ice start to melt and strong radiometric changes occur.


Sea ice is an integral part of the climate system, and an obstacle for the shipping and offshore industry. Satellite remote sensing is the method of choice to obtain hemispheric-scale information about sea ice and the snow cover on top. Microwave frequencies are ideally suited to observe sea ice/snow because they are largely independent of clouds and penetrate into the snow and sea ice.

The team is operating a ground-based multi-frequency scatterometer setup (systems operating at L-, C-, X-, Ku- and Ka-band frequencies) during the MOSAiC campaign (2019–2020) in the Central Arctic. The scatterometer observations are complemented by detailed in-situ measurements of snow and sea ice properties, and microwave radiometer measurements (P-, L-, C-, X-, K- and Ka-band).

To better interpret the measurements of current and future EUMETSAT/ESA/EU Copernicus satellite missions, validation with in-situ observations is needed. Furthermore, microwave radiative transfer (MRT) models of snow and sea ice need to be improved using coincident observations of ice/snow properties, along with scatterometer measurements. MRT models are required for the retrieval of sea ice and snow properties (e.g. ice thickness and snow depth on sea ice) from satellite missions such as Sentinel-3 and EPS-SG.

The scatterometer installation will be set up at one of the distributed monitoring stations surrounding Polarstern, as shown in Figures 2 and 3.

 Concept for Remote Sensing Sites
Figure 2: Concept for Remote Sensing Sites
 Remote Sensing Site set up
Figure 3: Remote Sensing Site set up
  Overview of the Remote Sensing Site 2 on 8 December 2019
Figure 4: Overview of the Remote Sensing Site 2 on 8 December 2019
 A visitor to the Remote Sensing Site
Figure 5: A visitor to the Remote Sensing Site

Status Update – August 2020

COVID-19 has had a significant impact on project logistics, causing an interruption in ground based measurements from mid-May to mid-June 2020. After drifting with the MOSAiC ice floe for many months, on 29th July 2020, the research camp was dismantled and the floe evacuated. Shortly after, the floe broke into several fragments.

The MOSAiC campaign will now focus on the start of the ice formation process and set course further north for the final leg of the expedition where the freezing phase will soon begin, reaching the North Pole on 19 August 2020. To date, team members and collaborators have submitted two abstracts for presentation at the AGU 2020 Fall Meeting.