Over land, permanent snow pack / sea ice is found mainly in the Northern hemisphere high altitude areas, the Arctic regions and Antarctica. An understanding of the interaction of light with snow / ice is an essential element to a diverse set of research areas, such as, investigations on climate feedbacks, ecology, atmospheric chemistry or hydrology. The Global Climate Observation System (GCOS) group working in partnership with the other global observing systems as identified Essential Climate Variables. Among these variables, one finds: snow cover, glaciers / ice caps extent and albedo. The monitoring of these variables using a global system of satellite observations and the establishment of requirement for remote sensing products is discussed in a dedicated GCOS report. In the frame of the Data User Programme, ESA is addressing user communities requesting snow and ice products. As such, the GlobSnow and GlobIce projects, are attempting to demonstrate that operational processing chains can be built to serve user communities with simple and robust snow and ice products. More complex product developments require detailed spectro-directional models of snow / ice covered surfaces to be developed.

Traceable scientific requirements:

The scientific requirements for this activity are derived from the Global Climate Observation System (GCOS) work and the GlobSnow and GlobIce ESA projects. Coordiantion with the latest will be ensured.

Description:

The overarching objective of this activity is to investigate snow / ice properties retrieval from current and future ESA passive imaging instruments operating in the UV to TIR spectral range. To meet this objective, it is required to the Contractor to:

• Review literature on snow / ice optical and physical properties, their retrieval from remote sensing payloads in the UV to TIR.
• Develop and validate a spectro-directional model from the UV to the TIR for snow / ice parameterized by physical parameters.
• Develop a forward model from UV to TIR for the coupled atmosphere + snow / ice system.
• Perform a sensitivity analysis of the TOA signal to snow / ice physical properties in spectral bands from ENVISAT/AATSR, ENVISAT/MERIS, S-3/OLCI, S-3/SLSTR, S-2/MSI and EarthCARE/MSI
• Develop a cloud / snow / sea ice detection algorithm for ENVISAT/MERIS and ENVISAT/AATSR taken separately and synergetically.
• Develop and validate a snow / ice properties retrieval algorithm based on ENVISAT/MERIS and ENVISAT/AATSR taken separately and synergetically.
• Provide recommendation for generation of snow / ice products from the S-2 / S-3 / EarthCARE missions and on new mission concepts.

Expected impact:

It is expected that this activity can be fed back into ENVISAT, S-3, S-2 and EarthCARE product development activities.