You are here


AEROSAT International Satellite Aerosol Science Network

Working Group on Pixel Level Uncertainties




To coordinate an exchange of work on pixel level and retrieval-region (“super–pixel”) level uncertainties in satellite aerosol

  • discuss different error propagation approaches.
  • discuss methods for validating pixel level uncertainties.
  • identify best practices for including pixel level uncertainties in satellite products.
  • discuss recommendations to users how these pixel level uncertainties shall be utilized.




  • Thomas Popp, DLR
  • Adam Povey, Oxford University
  • Gerrit de Leeuw, FMI & U. Helsinki
  • Rob Levy, NASA
  • Ralph Kahn, NASA
  • Yong, Xue, London Metropolitan University
  • Lucia Mona, IMAA


It is proposed for the second phase of ESA’s Aerosol_cci project (2014-2016) to install a working group on pixel level uncertainties. This working group shall review the initial approaches for pixel level uncertainties which have been implemented in Aerosol_cci until 2013 and work towards a harmonization of this uncertainty output in different Aerosol_cci products. Activities will be initiated with a dedicated workshop in the first half of 2014.


Once approved, this project working group will be open to external participants and can thus become a nucleus of the AERO-SAT WG on pixel level uncertainties. As a starting point activities on pixel level uncertainties within ESA (CCI project), NASA (MODIS, MISR teams) and GALION shall be intercompared; further interested groups are invited to contribute to discussions.


Activities & Schedule


WG duration: Three years.  At the end of this period the WG shall review its achievements in a final report and may recommend follow-on activities.


Year #1

  • Review methodologies applied for calculating pixel level uncertainties including underlying errors which are propagated
  • Discuss differences in the methods and learn from the approaches in other groups
  • Interact with accredited metrologists to improve quality and usability - as far as feasible - with the GUM (Guide for Uncertainties in Measurements) as a guide. (The GUM is not yet fully appropriate for satellite aerosol retrievals, consider proposing necessary additions)


Year #2

  • Review methods for validating pixel level uncertainties and discuss how the results can be interpreted
  • Review results of validating pixel level uncertainties define necessary improvements for the uncertainty calculation methods


Year #3

  • Based on the discussions in the first 2 years identify best practices for including pixel level uncertainties in satellite products and discuss recommendations to users how these pixel level uncertainties shall be utilized.