Comparison between the variability in the resolved infrared spectrum from observations and model simulations using reanalysis data
Abstract
Measurements of the spectrally resolved longwave energy emitted to space enable changes in the composition and structure of Earth's atmosphere to be detected. Detection and attribution of these changes and their variability are key to enabling a better understanding of how the climate is evolving, which in turn may lead to a better prediction of future climate. Here, we consider 3 years (2008 to 2010) of measurements from the Infrared Atmospheric Sounding Interferometer (IASI) instrument, and quantify the level of variability observed over a range of temporal and spatial scales, for both cloud-free and all-sky conditions. Regions of the outgoing longwave radiation (OLR) which exhibit the highest level of variability over seasonal and annual time scales are highlighted, and the level of variability observed in wavelength regions associated with key atmospheric parameters reported. These results are then compared to model simulations of the spectrally resolved outgoing longwave radiation. The model simulated spectra were calculated using the Reference Forward Model (RFM) and MODTRAN radiative transfer codes with surface temperature and atmospheric profile information prescribed from the European Centre for Medium Range Weather Forecast (ECMWF) Reanalysis Interim data set. The ability of the simulated spectra to represent the variability observed in the IASI measurements is then assessed. Finally, the impact of spectral, spatial and temporal sampling resolution on the ability to represent the variability observed is assessed, with the aim to inform and advise the requirements for future satellite missions focused on measuring changes in the Earth's spectrally resolved OLR.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2011
- Bibcode:
- 2011AGUFM.A13B0256B
- Keywords:
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- 0321 ATMOSPHERIC COMPOSITION AND STRUCTURE / Cloud/radiation interaction