final_program_abstracts[1]

11 IMSC Session Program
Observational system simulation experiments of CLARREO
shortwave reflectance spectra
Friday - Parallel Session 6
Daniel Feldman 1 , Chris Algieri 2 , Jonathan Ong 1 , William Collins 1,2
1
University of California-Berkeley, USA
2 Lawrence Berkeley National Laboratory, USA
The reflected solar spectrum contains information about climate forcings and
feedbacks and will likely change as a result of changes in the Earth’s climate.
Therefore, we have developed and extensively validated an Observational System
Simulation Experiment (OSSE) framework in order to analyze changes in reflectance
spectra over seasonal, annual, and decadal time-scales. OSSEs have been widely
utilized with infrared spectra, but are a novel approach to exploring the utility of
visible and near-infrared measurements. This OSSE couples the NCAR CCSM
climate model with the MODTRAN radiative transfer code to calculate spectra that
simulate IPCC AR4 emissions scenarios. We have found that the spectral signature of
aerosol forcing changes are substantial relative to natural variability and are confined
to lower latitudes. The signatures of low-cloud feedbacks and snow and ice-albedo
changes are also readily detectable from the reflectance spectra. We also tested the
reflectance spectra residuals associated with CCSM runs with different cloud
feedback strengths to gauge the magnitude of the signal. The results of the OSSE
suggest that the proposed NASA CLARREO mission to record highly-calibrated
infrared and shortwave spectra from a satellite platform may help detect climate
forcings and feedbacks more quickly than conventional satellite instruments.
Abstracts 358