MTG-S A Spot



Monitoring air quality trace gases and aerosols

MTG-S A Spot
MTG-S A Spot

Copernicus Sentinel-4 will monitor air quality, trace gases and aerosols over Europe hourly at high spatial resolution.

Last Updated

22 September 2023

Published on

19 May 2020

Sentinel-4 covers the need for continuous monitoring of atmospheric composition. The mission will focus on air quality, with the main data products being ozone (O3), nitrogen dioxide (NO2), sulphur dioxide (SO2), formaldehyde (HCHO) and aerosol optical depth.

The instruments used for the Sentinel-4 mission will be carried on Meteosat Third Generation satellites. The Sentinel-4 mission is made up of the Ultraviolet Visible Near-infrared (UVN) spectrometer and data from the Infrared Sounder (IRS), both on the MTG-Sounder (MTG-S) satellite.

The InfraRed Sounder will operate in synergy with the UVN spectrometer, to provide a unique, integrated capability to observe ozone, carbon monoxide, sulphur dioxide and other trace gases, in support of air quality, pollution and climate monitoring.

UVN characteristics

The UVN is a spectrometer measuring in the ultraviolet (UV: 305–400nm), the visible (VIS: 400–500nm) and the near infrared (NIR: 750–775nm), with a spatial sampling distance of around 8km.

Its observations are restricted to European area coverage, from 30 to 65º N in latitude and 30º W to 45º E in longitude, depending on seasonality (Figure 1). The observation repeat cycle period will be approximately one hour.

Spectral range
Figure 1: Instrument domain characteristics

Properties of the UVN Spectrometer:

  • An operational field of view of 3.85° north-south, and 11.2° east-west.
  • Pushbroom scanning in E/W direction at hourly frequency.
  • Imaging Spectrometer:
    • Telescope + UV-VIS & NIR spectrographs.
    • Full refractive optics except the scan mirror (23 elements/19 lenses).
  • Two silicon CCDs detectors cooled to ≈ 215K.
  • High-performance onboard calibration sources (solar diffusers, white light source, LEDs).
  • Mass = 150kg
  • Power = 180W
  • Data rate = 25Mbit/s

UVN Spectral Information

  • Band: UV-VIS1
    Spectral range (nm): 305–400
    Spectral resolution (nm): 0.5
  • Band: UV-VIS2
    Spectral range (nm): 400–500
    Spectral resolution (nm): 0.5
  • Band: NIR
    Spectral range (nm): 750–775
    Spectral resolution (nm): 0.12

Further details on the Sentinel-4 mission can be found on the ESA Sentinel-4 mission page.