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Instrument Overview

GOMOS ozone assimilated field
GOMOS ozone assimilated field

The Global Ozone Monitoring by Occultation of Stars (GOMOS) instrument was an atmospheric sensor on board the Envisat satellite, operational from 2 March 2002 to 8 April 2012. GOMOS was an ESA funded instrument and developed as a joint project of Finland and France. It contributed, together with SCIAMACHY and MIPAS, to atmospheric sounding and the monitoring of ozone with high accuracy.

The main scientific objective of this stellar occultation instrument was to monitor ozone and ozone trends in the stratosphere and mesosphere with high accuracy and high vertical resolution at global coverage. Moreover, GOMOS enabled measuring atmospheric parameters related to stratospheric ozone chemistry like NO2, NO3, H2O and aerosol as well as ozone dynamics like temperature, air density and turbulence. These tasks were achieved by measuring stellar spectra in the ultraviolet to near infrared range while stars are being eclipsed by Earth. It was regarded as a demonstrator for the stellar occultation technique and a precursor for other occultation instruments.


Data Description

All Envisat GOMOS products, in accordance with ESA Earth Observation Data Policy, are freely available to registered users via FTP. Read more about the available products and the registration process which is required to access them:

Data Tools

Tools available for visualising, processing and analysing GOMOS data:


The Atmospheric Toolbox (also known as BEAT) is a collection of executable tools and an application programming interface (API) which has been developed to facilitate the utilisation, viewing and processing of ESA GOMOS, MIPAS, SCIAMACHY and GOME data.

Auxiliary Data

Auxiliary data from ground or airborne sources is sometimes used to help produce data products. Auxiliary data files for GOMOS data products are available to download.


The goal of GOMOS calibration and validation activities was to verify the accuracy and quality of data the instrument acquired.

GOMOS Quality Control Reports

Quality Control is monitoring routinely the status of the spacecraft (payload and platform) and to check if the derived products meet the quality requirements along mission life-time. The GOMOS Quality Control Reports include Daily and Monthly Quality Reports and Products Availability.