Level-2 Algorithms - Ozone (O3) Full and Tropospheric Vertical profiles

Sentinel-5P Technical Guide - Level-2 Processing Overview - O3 Vertical Profiles

There are two O3 vertical profile output products:

  • full O3 profile
  • tropospheric O3 profile.

The retrieval algorithm is similar for both products and uses an Optimal Estimation Method (OEM). However, the wavelength fitting window differs for the two products. For the retrieval of TROPOMI O3 profiles, the a priori profile of ozone will be taken from the TOMS V8 climatology.

 

Fitting Window

  • For retrieval of the full O3 profile, the wavelength range used for the fit is 270 – 320 nm (spectral bands 1 and 2).
  • For retrieval of the tropospheric O3 profile the wavelength range used for the fit is 300 – 320 nm (spectral band 2). The tropospheric ozone profiles will not be retrieved if a significant amount of elevated absorbing aerosol is present, based on a threshold value for the absorbing aerosol index.

Because of the difference in spatial sampling between the different spectral bands, there is also a difference in spatial resolution for these two products. The full O3 profile has a spatial resolution of 21x28 km2 (ALT x ACT) limited by the spatial sampling of spectral band 1 (270 - 300 nm). The tropospheric O3 profile, which uses only spectral band 2 (300 – 320 nm) has a maximum spatial resolution of 7x7 km2.