Forest fire. Credit: gilitukha

Sentinel-3 NRT FRP processing baseline 1.2 released soon


Photo credit: gilitukha

Forest fire. Credit: gilitukha
Forest fire. Credit: gilitukha

The new processing baseline (PB) FRP_NR.001.02 of the Copernicus Sentinel-3 Near Real Time (NRT) Fire Radiative Power (FRP) product, derived from SLSTR, will be released on 6 May 2021, providing enhanced observation of small fires.

Last Updated

04 October 2022

Published on

29 April 2021

The PB 1.2 evolutions provide enhanced capability and increased confidence on the characterisation of small point sources, such as industrial gas flares, weakly radiative fires, and volcano activities.

The key changes introduced in FRP_NR.001.02 are:

  • Various probabilistic confidence class indexes are now introduced for each fire pixel identified with the Standard FRP MWIR, including the Clear-Sky Split Window which is of high importance to avoid false alarms caused by cloud-edges in the vicinity (see example over Western Australia).
  • A new method, named Alternative FRP MWIR, is added as an alternative technique for hot-spot detection and FRP computation from the MWIR spectral domain (3.7µm) (Figure 1). It relies much more on the SLSTR F1 (3.7µm) detector thanks to its low geometric distortion and more stable pixel size across the full SLSTR swath. It combines key scientific ideas from (Xu et al., 2020, 2021), together with a special risk mask specified and implemented by EUMETSAT, to avoid the high risk of false alarms due to the special F1 radiometry behaviour (so-called 'over-shooting', black areas in example of Brightness Temperature product).
  • The FRP SWIR (1km) technique is improved, in terms of detection capability and FRP computation quality. It mainly benefits from
    1. a correction of the radiometric calibration that is applied to all the SLSTR L1B S5-S6 Top-Of-the-Atmosphere (TOA) radiances (i.e. 1. µm & 2.25µm);
    2. a correction in the H2O transmission correction;
    3. an evolution of the South Atlantic Anomaly (SAA) detection from a binary flag to a probabilistic (in %) Confidence Class.
  • A new fine resolution FRP SWIR is introduced at 500m (Figure 2). This is of high relevance for point sources such as gas flares.
  • Angles (solar, viewing, zenith and azimuth) are now directly provided for each fire pixel identified with the Standard FRP MWIR, Alternative FRP MWIR and/or SWIR (1km). Note: the ancillary file file is no longer produced.
Standard & Alternative FRP MWIR
Figure 1: Standard & Alternative FRP MWIR night-time over India, 24 April 2021. Alternative FRP MWIR usually produces a higher number of MWIR hot-spots, most aren't false alarms due to the used F1 radiance Over-Shooting mask. Average FRP MWIR values are also lower, showing a higher sensitivity to weak or small fires.
Fine resolution SWIR
Figure 2: Fine resolution SWIR (500m) hot-spots applied to the detection of industrial gas flares in the North Sea during night-time. Left: SLSTR S6 radiance at the top of the atmosphere (only values higher than are depicted with dots). Right: As left but with detected SWIR hot-spots at 500m resolution overlaid (red crosses).

For full details, see the Product Notice and Product Format Description documents. A validation report will be available soon.

See also:

A special quality routine monitoring visualisation interface is under preparation and will soon be made public.

A series of partial reprocessed datasets covering the periods of 2019–2021 can be made available upon request.

Note: The FRP product is currently mostly generated during night-time. Developments are ongoing for FRP data during daytime.

For more information, contact our User Service Helpdesk.