Sentinel-5P TROPOMI
Date modified: February 2025
Overview
Background
Sentinel-5P is an Earth observation satellite launched in 2017 and operated by the European Space Agency under the Copernicus Programme (ESA, 2023). It was developed as a precursor mission to the future Sentinel-5 satellite to ensure continuity of atmospheric composition observations following earlier European missions such as SCIAMACHY, GOME, and GOME-2 (Veefkind et al., 2012; Munro et al., 2016). The core objective of Sentinel-5P is to provide near-real-time, global measurements of atmospheric composition and air quality, supporting scientific research, environmental monitoring, and policy implementation related to air pollution, climate change, ozone depletion, and human health (ESA, 2023; Copernicus, 2022). Its datasets enable scientists to track pollutants and trace gases spatially and temporally across the globe with continuous daily coverage.
Sentinel-5P carries a single instrument—the TROPOMI (Tropospheric Monitoring Instrument)—which measures solar radiation reflected from the Earth’s atmosphere and surface across ultraviolet, visible, near-infrared, and shortwave infrared spectral bands (Veefkind et al., 2012). Using these measurements, concentration values for various trace gases and aerosol properties are retrieved, including NO₂, SO₂, O₃, CO, CH₄, HCHO, and UV Aerosol Index. Compared to previous instruments, TROPOMI provides unprecedented spatial resolution and sensitivity, enabling detection of localised emission sources such as urban pollution, industrial stacks, biomass-burning plumes, and methane point sources (Landgraf et al., 2016; ESA, 2023).
Level-2 products represent geophysical variables derived from calibrated radiance measurements and converted into physically meaningful atmospheric quantities. These products describe key atmospheric components—trace gases, aerosols, and cloud properties—that are essential for applications in air-quality monitoring, weather forecasting, and climate-system analysis (van Geffen et al., 2022).
Sentinel-5P TROPOMI Level-2 Products and Their Functions
UV Aerosol Index (UVAI) detects light-absorbing aerosol particles such as smoke, dust, volcanic ash, and industrial pollution using UV spectral contrast. It is especially effective over bright surfaces and water, supporting monitoring of transboundary smoke transport, dust storms, and aerosol-related air-quality hazards (ESA, 2023; Torres et al., 2018).
Methane (CH4) Column-Averaged Mixing Ratio provides average methane concentrations in the atmosphere, retrieved from shortwave infrared absorption. It enables detection of methane “hotspots” from coal mining, oil and gas activity, agriculture, wetlands, and waste sites, supporting greenhouse gas inventories and climate-change mitigation (Butz et al., 2012; ESA, 2023).
Cloud fraction quantifies the portion of each pixel obscured by clouds, which strongly influences trace-gas retrieval accuracy. Cloud fraction is essential for filtering low-quality observations and understanding cloud cover patterns in climate and atmospheric studies (Koelemeijer et al., 2002).
Cloud albedo measures how much sunlight is reflected by clouds and supports assessments of cloud radiative effects, cloud–aerosol interactions, and corrections applied to gas retrievals (Stammes et al., 2008).
Cloud top pressure provides an estimate of cloud height and supports analysis of atmospheric convection, storm systems, and vertical structure used in atmospheric modelling and radiative transfer calculations (van Geffen et al., 2021).
Carbon Monoxide (CO) total column detects atmospheric CO using infrared absorption and serves as a tracer of incomplete combustion. CO is widely used to monitor biomass burning, industrial emissions, traffic pollution, and long-range smoke transport across Africa (Landgraf et al., 2016).
Formaldehyde (HCHO) total column indicates emissions from vegetation, industry, and biomass burning. As a short-lived product of VOC oxidation, it is a proxy for ozone precursor activity and helps quantify fire intensity and ecosystem stress (De Smedt et al., 2018; ESA, 2023).
Nitrogen Dioxide (NO2) total column measures the total atmospheric abundance of NO₂, supporting assessments of pollution trends, atmospheric chemistry, and satellite validation over regional and continental scales (van Geffen et al., 2022).
Ozone (O3) total column captures the total ozone layer thickness and supports monitoring of stratospheric ozone recovery, UV shielding, atmospheric health, and tropospheric ozone chemistry (Tilstra et al., 2021; ESA, 2023).
Sulfur Dioxide (SO2) total column detects SO₂ from volcanic eruptions, coal-fired power stations, and industrial activities. It is used in volcanic early warning systems, aviation hazard monitoring, and regional air-quality management (Theys et al., 2017).
Specifications
Relevant coverage and metadata for each of the datasets can be viewed on DE Africa Metadata Explorer:
A Jupyter Notebook which demonstrates loading and visualisng the products in the Sandbox is also available.
Sentinel-5P TROPOMI Level-2 Product Specifications
Sentinel-5P is dedicated to atmospheric composition monitoring, providing daily global measurements of trace gases, aerosols, and cloud properties. Its TROPOMI instrument captures ultraviolet, visible, near-infrared, and shortwave-infrared radiation, enabling the retrieval of key atmospheric pollutants at high temporal frequency. The tables below summarise the general characteristics of Sentinel-5P Level-2 products and present individual specifications for each trace-gas dataset available through Digital Earth Africa.
Specification |
Sentinel-5P TROPOMI Level-2 (Trace Gas Products) |
|---|---|
Cell size |
-0.01, 0.01 |
Coordinate Reference System |
EPSG:4326 (WGS 84) |
Temporal resolution |
Daily global coverage |
Temporal range |
2018 – Present |
Parent dataset |
Sentinel-5 Precursor TROPOMI (UV–VIS–NIR–SWIR) |
Update frequency |
Near-Real-Time (NRT) & Offline L2 (∼1–3 days) |
Access |
Free and open via DE Africa |
Below are the product-specific specifications for each major atmospheric variable.
Specification |
Sentinel-5P TROPOMI L2 UVAI |
|---|---|
Variable name |
|
Unit |
Unitless |
Expected range |
-1 to 5 (positive indicates absorbing aerosols) |
Spectral bands |
340–380 nm & 354–388 nm |
Use cases |
Smoke, dust storms, volcanic ash, absorbing aerosols |
Specification |
Sentinel-5P TROPOMI L2 CH4 |
|---|---|
Variable name |
|
Unit |
Parts Per Billion (PPB) |
Expected range |
1600 to 2000 |
Spectral band |
SWIR (2.3 µm) |
Use cases |
Coal mines, wetlands, gas leaks, agriculture |
Specification |
Sentinel-5P TROPOMI L2 CO |
|---|---|
Variable name |
|
Unit |
mol/m² |
Expected range |
0 to 0.1 mol/m² |
Spectral band |
SWIR (2.3 µm) |
Use cases |
Biomass burning, vehicles, industry, atmospheric transport |
Specification |
Sentinel-5P TROPOMI L2 HCHO |
|---|---|
Variable name |
|
Unit |
mol/m² |
Expected range |
0 to 0.001 mol/m² |
Spectral band |
UV (330–360 nm) |
Use cases |
Biomass burning, VOC emissions, precursors to O₃ |
Specification |
Sentinel-5P TROPOMI L2 NO2 |
|---|---|
Variable names |
|
Unit |
mol/m² |
Expected range |
0 to 0.0003 mol/m² |
Spectral band |
UV–VIS (405–465 nm) |
Use cases |
Power plants, traffic, industry, pollution hotspots |
Specification |
Sentinel-5P TROPOMI L2 O3 |
|---|---|
Variable name |
|
Unit |
mol/m² |
Expected range |
0 to 0.36 mol/m² |
Spectral band |
UV (270–330 nm) |
Use cases |
Stratospheric ozone, UV-shield monitoring, pollution chemistry |
Specification |
Sentinel-5P TROPOMI L2 SO2 |
|---|---|
Variable name |
|
Unit |
mol/m² |
Expected range |
0 to 0.01 mol/m² |
Spectral band |
UV (310–330 nm) |
Use cases |
Power plants, volcanoes, industrial emissions |
Geographic Extent
Specific temporal and geographic extents for the product can be explored interactively using the Digital Earth Africa Metadata Explorer.
Figure 1: Sentinel-SP TROPOMI geographic extent
Processing
The complete processing methodology for these products is detailed in the Technical Manual.
License
CC BY Attribution 4.0 International License
Acknowledgments
The Sentinel-5P TROPOMI Level-2 atmospheric composition products are produced by the European Space Agency (ESA) under the Copernicus Programme and are freely available through the Copernicus Open Access Hub and the Copernicus Data Space Ecosystem. Data access, processing, and regional support are enabled by Digital Earth Africa.
Data Access
Amazon Web Services S3
The Digital Earth Africa Sentinel-SP Tropomi product can be accessed from the associated S3 bucket.
Table 5: AWS data access details
AWS S3 details |
|
|---|---|
Bucket ARN |
|
Product name |
|
The bucket is located in the region af-south-1 (Cape Town)
Table 6: AWS file path convention
File path element |
Description |
Example |
|---|---|---|
|
|
|
|
Product version |
|
|
path number ranging from |
|
|
row number ranging from |
|
|
Year the data was collected |
|
|
Month of the year the data was collected (with leading zeros) |
|
|
Day of the month the data was collected (with leading zeros) |
|
OGC Web Services (OWS)
This product is available through DE Africa’s OWS.
Table 7: OWS data access details.
OWS details |
|
|---|---|
Name |
|
Web Map Services (WMS) URL |
|
Web Coverage Service (WCS) URL |
|
Layer names |
|
Digital Earth Africa OWS details can be found at https://ows.digitalearth.africa/.
For instructions on how to connect to OWS, see this tutorial.
Open Data Cube (ODC)
The Sentinel-5P TROPOMI collection can be accessed through the Digital Earth Africa ODC API, which is available through the Digital Earth Africa Sandbox.
ODC product name: s5p_tropomi_l2_aer_ai, s5p_tropomi_l2_ch4, s5p_tropomi_l2_cloud, s5p_tropomi_l2_co, s5p_tropomi_l2_hcho, s5p_tropomi_l2_no2, s5p_tropomi_l2_o3, s5p_tropomi_l2_so2
References
Butz, A., Guerlet, S., Hasekamp, O., Frankenberg, C., Schepers, D., & Aben, I. (2012). Towards accurate CO₂ and CH₄ observations from GOSAT. Atmospheric Chemistry and Physics.
Copernicus. (2022). Copernicus Sentinel-5P Mission Overview. European Commission.
De Smedt, I., et al. (2018). Improved retrievals of formaldehyde from TROPOMI. Atmospheric Measurement Techniques.
ESA. (2023). Sentinel-5P/TROPOMI Product Specification Documents. European Space Agency.
Koelemeijer, R. B. A., et al. (2002). Cloud and aerosol retrieval from satellite measurements. Journal of Geophysical Research.
Landgraf, J., et al. (2016). Carbon monoxide retrieval with TROPOMI. Atmospheric Measurement Techniques.
Liu, F., et al. (2020). NO₂ pollution mapping with TROPOMI. Science Advances.
Munro, R., et al. (2016). Evolution of GOME-2 and its role in atmospheric monitoring. Atmospheric Measurement Techniques.
Stammes, P., et al. (2008). UV–VIS cloud and albedo retrieval algorithms. Atmospheric Measurement Techniques.
Theys, N., et al. (2017). SO₂ retrievals from TROPOMI. Atmospheric Measurement Techniques.
Torres, O., et al. (2018). Aerosol Index from TROPOMI. Journal of Geophysical Research.
van Geffen, J., et al. (2021). Cloud parameter retrieval for TROPOMI. Atmospheric Measurement Techniques.
van Geffen, J., et al. (2022). NO₂ retrieval improvements for TROPOMI. Atmospheric Measurement Techniques.
Veefkind, J. P., et al. (2012). TROPOMI on the ESA Sentinel-5 Precursor: Mission Preparation and Calibration. Atmospheric Measurement Techniques.