Scientific Evaluation of mission concepts snow mass and other cryospheric parameters

Current satellite observing systems lack the capability to derive terrestrial snow mass and other parameters related to seasonal snow cover (e.g. snow melt-refreeze cycles) at the spatial resolution, synoptic sensitivity, and global coverage required for observational needs and operational environmental prediction. This is a significant gap because increases in mid- and high latitude air temperatures at a rate well above the global average has led to reductions in the extent and mass of seasonal snow cover across the Northern hemisphere, with impacts on the global climate system and increased vulnerability of snow as a vital freshwater resource. The required combination of revisit time, spatial coverage, measurement resolution, and sensitivity to the mass of snow on the ground necessitates a new observing concept in order to provide fundamental estimates of global snow water equivalent (SWE) for use in environmental prediction systems on time scales ranging from days (numerical weather prediction) to months (seasonal prediction) to decades (evaluation of climate projections).
SnowConcept aims to investigate the scientific need, requirements, and feasibility for a new satellite mission concept focused on the retrieval of terrestrial snow mass and other cryosphere variables on both global and regional scales. This is done by first consolidating the most pressing scientific needs, followed by the requirements these impose on satellite measurements, leading to mission characteristics. These, in turn, enable a critical review of suitable sensor technologies. Realistic technical and budgetary constraints are accounted for by restricting the analysis to foreseeable techniques with a relatively high scientific and technical maturity, as well as accounting for the typical scale in resources allocated to the Earth Explorer program by ESA. These criteria lead to a down-selection of one or several sensor options, with a preliminary identification of the main technical specifications (wavelength, imaging technique etc.). Forward modelling analyses, as well as extensive experimental datasets collected during the CoReH2O (Cold Regions Hydrology High-resolution Observatory) mission Phase A, as well as other international initiatives, are applied to support the analysis. The focus of the activity is set on microwave instruments, and notably on active microwave (radar). Nevertheless, other techniques such as passive microwave and altimetry are included in the analysis and down-selection. Advanced methods such as using SAR polarimetry and interferometry are also considered.
SnowConcepts is a joint project by the Finnish Meteorological Institute (Finland), ENVEO Environmental Earth Observation Information Technology GmbH (Austria), German Aerospace Centre (Germany), Gamma Remote Sensing AG (Switzerland), Institute of Applied Physics “Nello Carrara” (Italy), and Environment and Climate Change Canada (Canada). The study is funded by the European Space Agency.