ACCURAID - Aid to ACCURATE Climate Satellite Mission Preparations for Backing the Austrian Leading Role

ACCURATE was proposed in 2005 by an international team of more than 20 partners from more than 12 countries to an ESA (European Space Agency) selection process for the next Earth Explorer Missions.

Within a stringent peer assessment process it received very positive evaluation and recommendations for further study. Based on this, the concept undergoes scientific performance analyses as well as technical preparations on instrumentation.

ACCURATE employs the occultation measurement principle, known for its unique combination of high vertical resolution, accuracy and long-term stability, in a novel way in a Low Earth Orbit (LEO) inter-satellite configuration. It combines use of highly stable signals in the microwave 17-23/178-200 GHz bands (LEO- LEO MW occultation) with laser signals in the short-wave infrared 2-2.5 micron band (LEO-LEO IR laser occultation).

The parameters observed include fundamental atmospheric variables from the MW bands (temperature, pressure, humidity), complemented by line-of-sight wind and six key greenhouse gases (GHGs) and chemistry species from the SWIR band (H2O, CO2, CH4, N2O, O3, CO; and main CO2 and H2O isotopes).

ACCURATE is set to provide benchmark data for future monitoring of climate, GHGs, and chemistry changes of unprecedented quality, including the first height-resolved atmospheric measurements of CO2 and its isotopes (allowing to separate anthropogenic from natural CO2 sources) with global coverage.

In order to back the Austrian scientific leading role on ACCURATE, the project ACCURAID initiated an assessment of the scientific utility and performance of the novel LEO-LEO IR laser occultation part of ACCURATE; the LEO-LEO MW occultation part had already been studied to some extent in previous ESA study work.

Focussing on this, ACCURAID was a crucial preparatory and accompanying study in the context of ACCURATE mission development. In particular, two main lines of work were pursued: 1) enhancement of an end-to-end radio and MW occultation simulation tool ("EGOPS") for enabling quasi-realistic simulations of IR laser occultation data as well, 2) initial end-to-end analysis of the performance for GHG and isotope profile retrievals from these IR data.

Coordinater

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

Partners

• Institute of Atmospheric Physics - Prof. Ulrich Schumann, DLR Oberpfaffenhofen, Munich
• Department of Chemistry, University of York, U.K. - Prof. Peter Bernath
• Department of Atmospheric Sciences, University of Arizona, Tucson - Prof. E. Robert Kursinski
• and other Members of the International ACCURATE Team (more than 20 partners from more than 12 countries) and
• Members of ESA/ESTEC Technical Staff (Future Missions Division/Earth Observation Programmes) for specific ESA-related questions

Wegener Center for Climate and Global Change, University of Graz
Prof. Gottfried Kirchengast
Leechgasse 25
A-8010 Graz
Mail: gottfried.kirchengast@uni-graz.at
Web: www.wegcenter.at