Satellite observations are ideal for the synoptic observation of expansive and inaccessible areas, serving as both primary and secondary sources of information. However, global observing systems and in particular studies requiring different spatial resolutions and long time bases require accurate knowledge of sensor to sensor biases. Therefore the responsivities of all optical radiometers operated in space need to be intercompared and traceable to a common reference standard. CEOS (Committee on Earth Observing Satellites) has established a number of Earth targets to serve as international reference standards, such as polar sea ice and snow, needing to be well characterized by surface based in-situ measurements. The reflectance of natural surfaces being non-isotropic, knowing the bidirectional reflectance distribution function (BRDF) of natural surfaces is a pre-requisite for the use of satellite data.

In this project, we will measure multi-angular reflectance, also known as bidirectional reflectance distribution function (BRDF) of bare sea ice at the SERF facility. To do so, the team will deploy GRASS (Gonio-Radiometric Spectrometer System), an instrument that records quasi-simultaneous, multi-angle, hyperspectral measurements of the Earth’s surface reflectance. The main objectives of the project is to obtain a full BRDF dataset of bare sea ice, using the sun as a natural illumination source. The BRDF will be obtained as a function of solar zenith angle and ice thickness.

Fieldwork site: Sea Ice Environmental Research Facility (SERF), University of Manitoba, Winnipeg (Canada)

PI: M. Lamare/M.King

Project lead: M.King

Project Participants: Maxime Lamare (Royal Holloway University of London, UK); Dr. Martin King (RHL, University of London, UK); Claire Greenwell (National Physical Laboratory, UK)

Fieldwork summary/photo blog