Remote sensing of CO2 from the NASA OCO-2 satellite by RemoTeC

Abstract:

For a sound monitoring of the global distribution of atmospheric CO2 concentrations and their sources and sinks and the improvement of our ability to model those, precise measurements of atmospheric CO2 concentrations with global coverage and high spatial and temporal resolution are needed. The new NASA OCO-2 satellite, launched in July 2014, offers the capability to meet these needs. However, for the uptake of the OCO-2 data products by the science community, a profound analysis of the data quality and robust knowledge of the occurring retrieval errors is required.

Therefore, the RemoTeC algorithm, previously applied for the retrieval of column-averaged dry air mole fractions of carbon dioxide (XCO2) from measurements by the Greenhouse Gases Observing Satellite (GOSAT), is adapted to enable the retrieval of XCO2 from OCO-2 measurements. As the OCO-2 measurements are sensitive for the polarization of the reflected sunlight, the algorithm is expanded for polarization sensitive measurements by making use of a vector radiative transfer model. Furthermore, the algorithm is adjusted to deal with OCO-2 instrument specific aspects, such as data format and instrumental line shape. We compare the results with the OCO-2 Level 2 data product. Here, we report on first results.