Several organizations in the Netherlands are cooperating to develop user requirements and instrument concepts in the line of SCIAMACHY and OMI but with an increased focus on measuring tropospheric constituents from space. The concepts use passive spectroscopy in dedicated wavelength sections in the range of 300 to 2400 nm and wide angle, non-scanning, swath viewing.
To be able to penetrate into the troposphere small ground pixels are used to obtain a fair fraction of cloud-free pixels and to allow precise detection of the sources of polluting gases.
The trace gas products aimed for are O3, NO2, HCHO, H2O, SO2, Aerosol (optical depth, type and absorption index), CO and CH4, covering science issues on air quality and climate.
The main challenge in the instrument design is to obtain a good signal-to-noise for cloud free pixels and for low ground albedo and light levels. Also the retrieval of separated tropospheric and stratospheric column amounts from a nadir looking instrument is challenging.
The paper discusses the user requirements and compares alternative measurement strategies. It explains the selection of passive UV-Visible-NIR spectroscopy and comes with an instrument concept which provides the current best realisation of the user requirements.