This website uses cookies. By continuing to use this website you are agreeing to our use of cookies. 



Sentinel 5P: Sulphur Dioxide (SO2) Total Column level 2 data

Status: Ongoing
Online Status: ONLINE
Publication State: Preview
Publication Date:


Sentinel 5 Precursor (S5P) was launched on the 13th October 2017 carrying the TROPOspheric Monitoring Instrument (TROPOMI). Sulphur dioxide (SO2) enters the Earth’s atmosphere through both natural and anthropogenic processes. It plays a role in chemistry on a local and global scale and its impact ranges from short term pollution to effects on climate. Only about 30% of the emitted SO2 comes from natural sources; the majority is of anthropogenic origin. SO2 emissions adversely affect human health and air quality. SO2 has an effect on climate through radiative forcing, via the formation of sulphate aerosols. Volcanic SO2 emissions can also pose a threat to aviation, along with volcanic ash. S5P/TROPOMI samples the Earth’s surface with a revisit time of one day with unprecedented spatial resolution of 3.5 x 7 km which allows the resolution of fine details including the detection of much smaller SO2 plumes.

Citable as:  [ PROVISIONAL ] Copernicus; European Space Agency (9999): Sentinel 5P: Sulphur Dioxide (SO2) Total Column level 2 data. NERC EDS Centre for Environmental Data Analysis, date of citation.
Abbreviation: Not defined
Keywords: Sentinel, Sulphur Dioxide, SO2, TROPOMI


Previous Info:
No news update for this record
Previously used record identifiers:
No related previous identifiers.
Access rules:
Access to these data is available to any registered CEDA user. Please Login or Register for an account to gain access.
Use of these data is covered by the following licence: When using these data you must cite them correctly using the citation given on the CEDA Data Catalogue record.
Data lineage:

Data collected and prepared by European Space Agency (ESA). Downloaded from the Collaborative Hub for use by CEDA users.

Data Quality:
See dataset associated documentation.
File Format:
These data are in NetCDF format.

Process overview

This dataset was generated by a combination of instruments deployed on platforms and computations as detailed below.

Instrument/Platform pairings

TROPOspheric Monitoring Instrument (TROPOMI) Deployed on: Sentinel 5 Precursor

Computation Element: 1

Title Level 2 Sulphur Dioxide (SO2) total column processing algorithm applied to Sentinel 5P TROPOspheric Monitoring Instrument (TROPOMI) raw data
Abstract The baseline operation flow of the scheme is based on a DOAS retrieval algorithm and is identical to that implemented in the retrieval algorithm for HCHO (also developed by BIRA-IASB, see S5P HCHO ATBD [RD12]). The main output of the algorithm are SO2 vertical column density, slant column density, air mass factor, Averaging Kernels (AK), and error estimates. Here, we will first briefly discuss the principle of the DOAS VCD retrieval before discussing the separate steps of the process in more detail. First, the radiance and irradiance data are read from an S5P L1b file, along with geolocation data such as pixel coordinates and observation geometry (sun and viewing angles). At this stage also cloud cover information is obtained from the S5P cloud L2 data, as required for the calculation of the AMF, later in the scheme. Then relevant absorption cross-section data (SO2), as well as characteristics of the instrument (e.g., slit functions) are used as input for the SO2 slant column density determination. As a baseline, the slant column fit is done in a sensitive window from 312 to 326 nm. For pixels with a strong SO2 signal, results from alternative windows, where the SO2 absorption is weaker, can be used instead. An empirical offset correction (dependent on the fitting window used) is then applied to the SCD. The latter correction accounts for systematic biases in the SCDs. Following the SCD determination, the AMF is estimated. For computational efficiency, the algorithm makes no ‘on the fly’ calculation but uses a pre-calculated box air mass factor look-up table (LUT). This lookup-table is generated using the LIDORT radiative transfer code and has several entries: cloud cover data, topographic information, observation geometry, surface albedo, effective wavelength (representative of the fitting window used), total ozone column, and the shape of the vertical SO2 profile. The algorithm also includes an error calculation and retrieval characterization module that computes the so-called DOAS-type averaging kernels (Eskes & Boersma, 2003), which characterize the vertical sensitivity of the measurement and which are required for comparison with other types of data (Veefkind et al., 2012). For more information please look at the ATBD document on the TROPOMI website.
Input Description None
Output Description None
Software Reference None
Output Description None

No variables found.

Temporal Range
Start time:
End time:
Geographic Extent