Testing climate models using infrared spectra and GNSS radio occultation

Abstract

The Climate Absolute Radiance and Refractivity Observatory will be a climate benchmarking mission intended to include instruments for measuring Earth's atmospheric refractivity by GNSS radio occultation (RO), high spectral resolution thermal infrared spectra emitted from the Earth, and the spectrally resolved reflected shortwave spectrum. Climate benchmarking is necessary to establish a record that can be used to test climate models according to their predictive capability because other attempts at establishing trustworthy timeseries of satellite data have not been particularly successful. We have investigated how GNSS RO measurements and thermal infrared spectra can be used to test models' predictive capability. GNSS RO provides a constraint on the transient sensitivity of the climate system. Infrared radiance spectra can quantify the individual longwave feedbacks of the climate system, including cloud-longwave feedbacks when used in conjunction with GNSS RO. At present, studies are limited to clear sky infrared radiation, so the next research steps should include cloudy sky infrared simulations and reflected shortwave simulations. © 2009 Springer-Verlag Berlin Heidelberg.