Benchmarking Climate Model Top-of-atmosphere Radiance in the 9.6 Micron Ozone Band Using TES and IASI Observations

Biases of present day top-of-atmosphere (TOA) flux for the 9.6 micron ozone band predicted by IPCC chemistry-climate models have never been evaluated with measurements. Ozone band TOA flux biases impact the estimates of ozone radiative forcing (RF) from pre-industrial to present day. Satellite measurements of TOA radiances and ozone profiles allow evaluation of the performance of chemistry-climate models for both TOA flux and Instantaneous Radiative Kernels (IRK), which give the sensitivity of TOA flux to changes in the vertical distribution of atmospheric state, e.g. tropospheric ozone, water or temperature. We compute the ozone band flux and IRK from Aura-TES and MetOP-IASI spectral radiance measurements. The new version of IRKs from TES have been upgraded from the single-angle anisotropy approximation to the more accurate 5-angle Gaussian quadrature integration method and the IRKs are expanded for quantities other than ozone, such as water vapor, temperature, and cloud at this ozone band. These IRKs can be used to attribute changes in ozone band flux to vertical changes in ozone, water vapor and atmospheric temperature, which will help to assess the feedback from vertical changes in the hydrological cycle on the ozone RF. We present comparisons of satellite observed TOA ozone band fluxes and IRKs with RRTMG (Rapid Radiative Transfer Model-GCM applications) in the NCAR CAM-chem chemistry/climate model and with the GISS radiative transfer model. TES observations of ozone and its radiative effect will be used to evaluate the Atmospheric Chemistry Climate Model Intercomparison (ACCMIP) and the Chemistry Climate Model Initiative (CCMI) ensembles in terms of their simulated tropospheric ozone distributions, their effect on TOA flux, and their predictions of future ozone forcing.