Nitrogen dioxide (NO2) and nitrogen oxide (NO) together are usually referred to as nitrogen oxides (NOx = NO + NO2). They are important trace gases in the Earth’s atmosphere, present in both the troposphere and the stratosphere. They enter the atmosphere as a result of anthropogenic activities (notably fossil fuel combustion and biomass burning) and natural processes (such as microbiological processes in soils, wildfires and lightning). Approxiately 95% of the NOx emissions is in the form of NO. During daytime, i.e. in the presence of sunlight, a photochemical cycle involving ozone (O3) converts NO into NO2 (and vice versa) on a timescale of minutes, so that NO2 is a robust measure for concentrations of nitrogen oxides. Tropospheric and stratospheric concentrations of NO2 are monitored all over the world by a variety of instruments either ground-based, in-situ (balloon, aircraft), or satellite-based– each with its own specific advantages.
The TROPOMI NO2 processing system is based on the DOMINO system, developed for NO2 retrieval for OMI, with improvements related to TROPOMI and state-of-the-art scientific insights. The basis for the processing is a retrieval-assimilation-modelling system which uses the 3-dimensional global TM5 chemistry transport model (CTM) as an essential element. The retrieval consists of a three-step procedure, performed on each measured Level-1b spectrum.
USER DOCUMENTATION: ATBD
The Algorithm Theoretical Basis Document (ATBD) can be found by clicking here.
PUM & SAMPLE DATA
The Product User Manual (PUM) and Sample Data Files are being updated based on a new release of the processing software and will be available for download by mid-May 2017.
After launch, preliminary product results will be provided during the Commissioning Phase and the Operational Phase.