ACCU-Clouds - Preparing a Key Dimension of ACCURATE Climate Utility: Cloud sensing and Greenhouse Gas Profiling in Cloudy Air

Overall ACCU-Clouds represents a crucial milestone on the way towards realizing an ACCURATE mission for the benefit of monitoring the changing atmospheric composition and climate in the 21st century.

Short Description

The ACCURATE (Atmospheric Climate and Chemistry in the UTLS Region and Climate Trends Explorer) satellite mission enables joint atmospheric profiling of greenhouse gases, thermodynamic variables, and wind in the upper troposphere and lower stratosphere (UTLS) and beyond. It achieves this unprecedented scope by employing inter-satellite signal links between Low Earth Orbit (LEO) satellites, combining LEO-to- LEO microwave occultation with LEO-to-LEO infrared-laser occultation (LIO).

This novel concept was conceived at the WegCenter and proposed by an international team of more than 20 scientific partners from more than 12 countries to an ESA selection process for future Earth Explorer Missions. While not selected for formal pre-phase A study in 2006, because it was partly immature at that time, it received very positive evaluations and was recommended for further study and development.

On this basis FFG-ALR has funded pioneering initial projects under previous ASAP calls (ACCURAID, EOPSCLIM) and ESA supports studies as well. ACCU-Clouds builds on these activities as an innovative project complementing the ESA studies in the key dimension of providing cloud sensing and cloudy-air greenhouse gas profiling capabilities.

Related to this pivotal potential for climate change monitoring and research, ACCU-Clouds prepares novel scientific algorithms for retrieving cloud extinction, cloud layering, and cloudy-air greenhouse gas profiles from LIO data. These algorithms are seamlessly embedded into WegCenter’s occultation software system (EGOPS), also used to integrate all ESA study developments.

Furthermore, in order to test the advanced system, an end-to-end performance analysis is undertaken, which uses the new cloudy-air greenhouse gas profiling capability to assess its uniqueness for climate science.

Results show that the detection of clouds works in a highly reliable way and greenhouse gas concentrations are accurately derived in all conditions not blocked by clouds.

Project Partners


University of Graz, Wegener Center for Climate and Global Change - Prof. Gottfried Kirchengast


  • University of Munich, Meteorological Institute - Claudia Emde
  • University of York (UK), Department of Chemistry - Prof. Peter Bernath
  • University of Arizona, Institute of Atmospheric Physics - Prof. Robert Kursinski

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