Develop a FDR for GOME & SCIAMACHY

Aug 24, 2020

The project FDR4ATMOS (Fundamental Data Records in the domain of satellite Atmospheric Composition) has been initiated by the European Space Agency (ESA). A Fundamental Data Record (FDR) is a long-term record of selected Earth observation Level 1 parameters (radiance, irradiance, reflectance), possibly multi-instrument, which provides improvements of performance with respect to the individual mission datasets. The focus of this project is a FDR for ozone and sulphur dioxide in the UV range, for nitrogen dioxide in the visible range from the time series data of GOME and Sciamachy.

The Instruments

GOME-1 and SCIAMACHY were spectral imagers. GOME-1 operated from 1995 to 2011 and SCIAMACHY operated from 2002 to 2012. The table below shows the instrument parameters relevant for the FDR generation1

Table 1: FDR relevant characteristics of the GOME and SCIAMCHY instruments. For SCIAMACHY, only the channels for the spectral range of GOME are shown.
Item GOME SCIAMACHY
Launch April 21st 1995 March 1st 2002
End of Mission September 5th 2011 April 8th 2012
Orbit sun-synchronous, 790 km sun-synchronous, 799.8km
Local Time (DNX) 10:30 am 10:00 am ± 5 Min
Observation Geometries Nadir Nadir, Limb, Occultation
Ground Pixel Size 40 × 320 km^2 32 × 233 km^2 to 26 × 30 km^2
Number of channels 3 8
Pixel Per Channel 1024 1024
Total Spectral Range 237 - 793 nm 212 - 2386 nm
UV Channel Range/Resolution 311 - 405 nm/0.17 nm 300 - 412 nm/0.26 nm
VIS Channel Range/Resolution 405 - 611 nm/0.29 nm 383 - 628 nm/0.44 nm
NIR Channel Range/Resolution 595 - 793 nm/0.33 nm 595 - 812 nm/0.48 nm

Both instruments also employ Polarisation Measurement Devices (PMDs); photocells with broadband spectral filters measuring one polarisation Direction.

Main Tasks

The final goal of the project is to build an operational processor that generates a FDR with associated uncertainties that can be used for further research. The methods and the processor shall also be easily extensible to include other instruments. On order to achieve this goal we have to:

  1. Define the requirements for the FDR, based on the needs of the Level 2 community
  2. Identify the parameters and calculate the uncertainties that should go into the final project
  3. Develop methods to harmonise the data from GOME and SCIAMACHY
  4. Implement the methods into an operational system
  5. Validate the results to ensure the data quality

The figure below shows a simplified Flow:

Figure 1: Simplified flow for the FDR development (Source: DLR).

  1. SCIAMACHY had an extended wavelength range, which is not shown here ↩︎

Günter Lichtenberg
Project Lead