Adjoint inversion using combined MOPITT, SCIAMACHY and AIRS CO columns
Abstract
To estimate carbon monoxide (CO) sources in the Northern Hemisphere, we combine CO column measurements from MOPITT (aboard Terra), SCIAMACHY (aboard ENVISAT) and AIRS (aboard Aqua) instruments in an efficient adjoint source inversion. The three instruments measuring CO from space deliver complementary information; MOPITT, as a thermal IR instrument, has been providing midand upper tropospheric CO abundances since its 1999 launch, SCIAMACHY as a solar backscatter instrument allows for sensitivity to the surface concentrations, while AIRS, also a thermal IR instrument, delivers unprecedented daily global datasets. Previous source inversion studies have mostly used individual datasets, while the current study investigates the benefit of using multiple measurements of varying vertical sensitivity, data density and data quality. Large uncertainties exist in the source estimates, and modeled concentrations show large disagreements with observations, particularly in matching the amplitude of the observed seasonal cycle. To consider the full extent of seasonal variation and to maximize the amount of available data, we use measurements over Northern Hemisphere between May 1, 2004 and May 1, 2005 from the three instruments. In the inversion, we compare CO column measurements to CO concentrations simulated by a Chemical Transport Model (CTM) GEOS-Chem. Since the efficient adjoint inversion method allows for extracting maximum information from very large data sets, we thus attempt to derive monthly source constraints at the spatial resolution of the underlying CTM, 4 degrees by 5 degrees.
- Publication:
-
37th COSPAR Scientific Assembly
- Pub Date:
- 2008
- Bibcode:
- 2008cosp...37.1579K