ATM-MPC Operational HCHO tropospheric column L2 data from TROPOMI (NRT and OFFL products)

Sentinel-5 Precursor Level 2 Formaldehyde (L2__HCHO__)

The TROPOMI instrument onboard Sentinel-5 Precursor is a nadir-viewing, imaging spectrometer covering wavelength bands between the ultraviolet and the shortwave infrared. The instrument uses passive remote sensing techniques to attain its objective by measuring, at the Top Of Atmosphere (TOA), the solar radiation reflected by and radiated from the earth.

Formaldehyde is an intermediate gas in almost all oxidation chains of Non-Methane Volatile Organic Compounds (NMVOC), leading eventually to CO2. NMVOCs are, together with NOx, CO and CH4, among the most important precursors of tropospheric O3. The major HCHO source in the remote atmosphere is CH4 oxidation. Over the continents, the oxidation of higher NMVOCs emitted from vegetation, fires, traffic and industrial sources results in important and localised enhancements of the HCHO levels.

In addition to the main product results, such as HCHO slant column, vertical column and air mass factor, the level 2 data files contain several additional parameters and diagnostic information.

The retrieval algorithm has been developed by BIRA-IASB and operationally implemented at DLR.

Algorithm description and validation:

• https://doi.org/10.5194/amt-11-2395-2018
• https://doi.org/10.5194/amt-13-3751-2020
• https://doi.org/10.5194/acp-21-12561-2021