Estimating atmospheric CO 2 from advanced infrared satellite radiances within an operational four‐dimensional variational (4D‐Var) data assimilation system: Results and validation
2005; American Geophysical Union; Volume: 110; Issue: D18 Linguagem: Inglês
10.1029/2005jd005982
ISSN2156-2202
AutoresRichard Engelen, A. P. McNally,
Tópico(s)Atmospheric Ozone and Climate
ResumoMore than a year of Atmospheric Infrared Sounder (AIRS) radiance observations have been assimilated in the European Centre for Medium‐Range Weather Forecasts four‐dimensional variational (4D‐Var) data assimilation system to estimate tropospheric CO 2 . The assimilation of a set of 18 spectral channels provides a mean tropospheric mixing ratio representing a layer between ∼700 hPa and the tropopause. Analysis errors for a 5‐day mean on a 6° by 6° averaging grid box are on the order of 1%. Comparisons with independent flight data from Japanese Airlines and National Oceanic and Atmospheric Administration Climate Monitoring and Diagnostics Laboratory are favorable. Differences between the averaged assimilation estimates and the onboard flask observations are generally within the 1‐σ error bars. Currently, this work is being extended by introducing CO 2 as a full assimilation model tracer variable, which will allow the operational monitoring of atmospheric CO 2 using AIRS observations and observations from upcoming instruments.
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