Advancing an Observational Estimate of the Cloud-albedo Effect Radiative Forcing

Allison McComiskey National Oceanic and Atmospheric Administration
Graham Feingold NOAA - Earth System Research Laboratory

Category: Aerosol-Cloud-Radiation Interactions

Working Group: Aerosol Life Cycle

Radiative forcing estimates of the cloud-albedo effect by the IPCC 4AR derive solely from model representations and are subject to high uncertainty. Observations of the cloud-albedo effect are not considered mature enough to provide a radiative forcing estimate; the uncertainty in existing observations may produce an uncertainty in radiative forcing several times that of the models. Several factors contribute to the difficulty in quantifying the cloud-albedo effect from observations. Foremost among these factors are: (1) variability in cloud liquid water path and failure to constrain this variability in calculations, (2) variability in vertical air velocities, and (3) variability in aerosol composition and size distribution. Failure to account for these factors tends to reduce the observed strength of aerosol impacts on cloud albedo and may be exacerbated by the observational platform or approach employed. We explore the impact of these factors, particularly their manifestation at different spatial scales, on the uncertainty in the observed cloud-albedo effect.

This poster will be displayed at ASR Science Team Meeting.

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