The Continual Intercomparison of Radiation Codes: Results from Phase I
We present results from Phase I of the Continual Intercomparison of Radiation Codes (CIRC), intended as an evolving and regularly updated reference source for evaluation of radiative transfer (RT) codes used in Global Climate Models. CIRC differs from previous intercomparisons in that it relies on an observationally validated catalogue of cases. The seven CIRC Phase I baseline cases, five cloud-free, and two with overcast liquid clouds, are built around observations by the Atmospheric Radiation Measurements (ARM) program that satisfy the goals of Phase I, namely to examine radiative transfer (RT) model performance in realistic, yet not overly complex, atmospheric conditions. In addition to the seven baseline cases, additional idealized "subcases" are also examined to facilitate intrepretation of the causes of model errors. In addition to summarizing individual model performance with respect to reference line-by-line calculations and inter-model differences, we also highlight RT model behavior for conditions of doubled CO2, aspects of utilizing a spectral specification of surface albedo, and the impact of the inclusion of scattering in the thermal infrared. Our analysis suggests that RT models should work towards improving their calculation of diffuse shortwave flux, shortwave absorption, treatment of spectral surface albedo, and shortwave CO2 forcing. On the other hand, LW calculations appear to be significantly closer to the reference results. By enhancing the range of conditions under which participating codes are tested, future CIRC phases will hopefully allow even more rigorous examination of RT code performance.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 1178525
- Report Number(s):
- PNNL-SA-83841; KP1704010
- Journal Information:
- Journal of Geophysical Research. D. (Atmospheres), 117(D6):Article No. D06118, Journal Name: Journal of Geophysical Research. D. (Atmospheres), 117(D6):Article No. D06118
- Country of Publication:
- United States
- Language:
- English
Similar Records
Mean fluxes of visible solar radiation in broken clouds
Radiative heating rate profiles over the southeast Atlantic Ocean during the 2016 and 2017 biomass burning seasons