completed in 2014

CO2 flux estimation by four-dimensional variational assimilation of in situ and remote sensing data

Research Area:
Atmospheric tracer simulations, chemical data assimilation, source estimation via inverse modeling

The goal of this project is to provide a CO2 Budget for the Rur catchment area including estimates with the 4D-var system EURAD-IM for anthropogenic and biogenic sources, biogenic sinks and lateral in- and outfluxes.

Boundary values will be provided by a nested CO2 transport simulation from European scale of 15 km resolution in steps of 5 km to 1 km Rur catchment resolution. The global lateral boundaries are taken from the MACC II project (MACC-GHG). Anthropogenic CO2 emissions have been downscaled from 0.7°*0.7° resolution TNO emission inventory to 1km*1km horizontal resolution for ten snap codes. Biogenic fluxes will be generated with CLM for the Rur catchment which accounts the heterogeneous pattens of the area. The atmospheric transport will play a key role in the EURAD-IM 4D-var system. On the one hand the forward tracer transport has to be realized with only few diffusion and in a contour preserving manner. On the other hand sensitivity studies with the adjoint transport model aim to optimize not only initial conditions, but also emission sources which shall distinguish anthropogenic and biogenic fluxes. For this purpose a new advection scheme, the Walcek scheme has been integrated in the EURAD-IM. The adjoint advection routine will be validated to quantify theoretical boundaries to which extent observation time series can get analyzed with the 4D-var EURAD-IM system.

Cooperation partner:

• FZ Jülich
• MACC II
• TNO