Minimize Heritage & Future
SENTINEL-5P continues a series of spectrometers that were or are currently measuring atmospheric properties since 1995 until today:
  • the Global Ozone Monitoring Experiment (GOME) on ESA's ERS-2 satellite which operated between 1995 and 2011.
  • GOME-2 on EUMETSAT's Met-OP-A satellite, launched in 2006, still in service. A second GOME-2 is operating since 2012 on MetOp-B satellite.
  • SCanning Imaging Absorption spectroMeter for Atmospheric CartograpHY (SCIAMACHY) on ESA's ENVISAT mission which operated between 2002 and 2012.
  • Ozone Monitoring Instrument (OMI) since 2004 on NASA's AURA spacecraft, still in service.

SENTINEL-5P will extend the data records of these missions and will be followed by the SENTINEL-5 missions, planned for launch in 2021 onwards.

The mission forms the link between the current missions and the future SENTINEL-4 and SENTINEL-5 missions.

GOME(-2), SCIAMACHY, OMI and TROPOMI are passive sun backscatter spectrometers. SCIAMACHY and GOME(-2) use a scanning concept and linear detector arrays whereas OMI uses a staring push-broom concept with two-dimension detector arrays. The staring push-broom concept measures all ground pixels in the swath simultaneously and allows improved spatial resolution. SCIAMACHY measurements cover almost the entire solar irradiance spectrum from UV to SWIR (240 to 2 400 nm) whereas GOME(-2) and OMI are scaled down in terms of wavelength range covering respectively the UV-VIS-NIR range (270 – 790 nm) and the UV-VIS range (270-500 nm). The main characteristics of these four heritage instruments are summarised in Table 1.

 

Table 1: Main Characteristics of SENTINEL-5P Heritage Instruments

Instrument

Technical Concept

Spectral Range

Spatial resolution (km x km)

Swath (km)

Overpass time

Operational

GOME

Whisk-broom (scanning)

UV-VIS-NIR (240-790 nm)

320 x 40

960

10:30 local time

1995-2011

GOME-2

Whisk-broom (scanning)

UV-VIS-NIR (240-790 nm)

80 x 40

1920

9:30 local time

2006-present

SCIAMACHY

Whisk-broom (scanning)

UV to SWIR (240-2400 nm)

30 x 215

1000

10:00 local time

2002-2012

OMI

Push-broom (staring)

UV-VIS (270-500 nm)

13 x 24

2600

13:30 local time

2004-present

 

TROPOMI employs the best of its predecessors by combining:

  • large wavelength range of SCIAMACHY (albeit with some gaps) where the SWIR band allows for detection of molecules like CH4 and CO.
  • OMI's staring concept to provide the combination of daily global coverage with high spatial resolution and good signal-to-noise ratio.

When compared to these heritage instruments, the 7×7 km2 spatial resolution at nadir and the improved signal-to-noise ratio of the TROPOMI instrument allows detection of small-scale sources, and increases the fraction of cloud-free observations. This represents a significant step forward in meeting the challenging requirements for SENTINEL-5.