EGU24-12496, updated on 09 Mar 2024
EGU General Assembly 2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.

Cloud characterization for trace gas retrievals over snow using O2-O2 and oxygen B-band absorption

Lukas Fehr, Daniel Zawada, Doug Degenstein, and Adam Bourassa
Lukas Fehr et al.
  • Atmospheric Research Group, University of Saskatcheawn, Saskatoon, Canada

Geostationary measurements of trace gases provide valuable air quality data at unprecedented temporal scales. At high latitudes challenges begin to arise, such as lines of sight that stray from nadir, and (during winter) limited sunlight and pervasive snow cover. Motivated by the desire to fully take advantage of TEMPO (Tropospheric Emissions: Monitoring of Pollution) measurements over Canada, we investigate one of these issues: snow.

A key challenge with measurements over snowy scenes is the similar reflectivity of snow and clouds. Trace gas algorithms rely on the contrast between surface and cloud reflectivities to estimate an effective cloud fraction which is necessary to characterize the light path for cloudy scenes. This snow-cloud ambiguity ultimately compromises the data quality, denying the opportunity to capitalize on the potential increase in surface sensitivity offered by the high reflectivity of snow. Here we present an algorithm that simultaneously uses O2-O2 and oxygen B-band absorption to extract cloud data for trace gas retrievals while reducing dependency on the surface-cloud reflectivity contrast.

How to cite: Fehr, L., Zawada, D., Degenstein, D., and Bourassa, A.: Cloud characterization for trace gas retrievals over snow using O2-O2 and oxygen B-band absorption, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12496,, 2024.