Top-of-atmosphere radiance simulations over snow-covered surfaces for satellite-based carbon dioxide remote sensing
Antti Mikkonen, Finnish Meteorological Institute, antti.mikkonen@fmi.fi (Presenter)
Hannakaisa Lindqvist, Finnish Meteorological Institute, hannakaisa.lindqvist@fmi.fi
Jouni Peltoniemi, Finnish Geospatial Research Institute, jouni.peltoniemi@nls.fi
Johanna Tamminen, Finnish Meteorological Institute, johanna.tamminen@fmi.fi
High latitudes pose significant challenges to reliable space-based observations of greenhouse gases. In addition to large solar zenith angles and frequent cloud coverage over the Arctic and boreal regions, snow-covered surfaces absorb strongly in the near-infrared wavelengths. Because of the resulting low radiances of the reflection measured by the satellite in nadir geometry, the retrievals over snow may be less reliable and are typically filtered or flagged for potentially poor quality.
Snow surfaces are highly forward-scattering and therefore the traditional nadir-viewing geometries over land might not be optimal and instead the strongest signal could be attainable in near-glint geometries. In addition, the contributions from the 1.6 um and 2.0 um CO2 absorption bands need to be evaluated over snow. In this work, we present a realistic, non-Lambertian surface reflection model of snow based on snow reflectance measurements and examine results of atmospheric radiative transfer simulations in various satellite observation geometries and the contributions from different absorption bands.
This research is carried out as part of a newly-funded ESA project SNOWITE, where the feasibility of satellite-based greenhouse gas remote sensing is examined in characteristic situations of high latitudes considering snow-covered and ocean surfaces. The project has relevance for CO2M mission planning but also has potential applicability for ongoing missions.
Poster: Poster_Mikkonen__79_25.pdf
Presentation Type: Poster
Session: 2.2a Retrieval algorithms and methods for inter-instrument and product Cal/Val
Session Date: Tuesday (6/15) 9:45 AM