Minimize Heritage

The SENTINEL-5 instrument inherits directly from its predecessor TROPOMI which is a UV-VIS-NIR-SWIR spectrometer embarked as the single payload of the satellite/mission SENTINEL-5 Precursor (or SENTINEL-5P).

 

The SENTINEL-5 instrument and TROPOMI are similar in their design, measurement principle and performances.

 

A description of the  SENTINEL-5P/TROPOMI mission can be found on the SENTINEL-5P/TROPOMI mission guide webpage.

 

As for SENTINEL-5P, the SENTINEL-5 mission continues a series of spectrometers measuring atmospheric properties since 1995:

  • 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.

GOME, 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 and TROPOMI use 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 the UV-VIS-NIR range (270 – 790 nm) and the UV-VIS range (270-500 nm) respectively. The Main characteristics of these five heritage instruments are summarized in Table 1.

 

Table 1: Main Characteristics of SENTINEL-5/UVNS 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 × 40

960

10:30 local time

1995-2011

GOME-2

Whisk-broom (scanning)

UV-VIS-NIR (240-790 nm)

80 × 40

1920

9:30 local time

2006-present

SCIAMACHY

Whisk-broom (scanning)

UV to SWIR (240-2400 nm)

30 × 215

1000

10:00 local time

2002-2012

OMI

Push-broom (staring)

UV-VIS (270-500 nm)

13 ×24

2600

13:30 local time

2004-present

TROPOMI

Push-broom (staring)

UV-VIS-NIR-SWIR (270 – 2385 nm)

7 × 7

2600

13:30 local time

Launch scheduled for 2016

SENTINEL-4

Push-Broom (scanning)

UV-VIS-NIR (305- 775 nm)

8 × 8

NA

Geostationary

Launch scheduled for 2021

SENTINEL-5

Push-broom (staring)

UV-VIS-NIR-SWIR (270 – 2385 nm)

7 × 7

2670

9:30 local time

Launch scheduled for 2021

 

SENTINEL-5 and SENTINEL-5P/TROPOMI employ 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 SENTINEL-5, SENTINEL-4 and TROPOMI instruments allows detection of small-scale sources, and increases the fraction of cloud-free observations.