Observational Constraint on Cloud Susceptibility Weakened by Aerosol Retrieval Limitations

TitleObservational Constraint on Cloud Susceptibility Weakened by Aerosol Retrieval Limitations
Publication TypeJournal Article
Year of Publication2018
JournalNature Communications
Volume9
Number1
Date Published07/2018
Abstract / Summary

Aerosol-cloud interactions remain a major uncertainty in climate research. Studies have indicated that model estimates of cloud susceptibility to aerosols frequently exceed satellite estimates, motivating model reformulations to increase agreement. Here we show that conventional ways of using satellite information to estimate susceptibility can serve as only a weak constraint on models because the estimation is sensitive to errors in the retrieval procedures. Using instrument simulators to investigate differences between model and satellite estimates of susceptibilities, we find that low aerosol loading conditions are not well characterized by satellites, but model clouds are sensitive to aerosol perturbations in these conditions. We quantify the observational requirements needed to constrain models, and find that the nighttime lidar measurements of aerosols provide a better characterization of tenuous aerosols. We conclude that observational uncertainties and limitations need to be accounted for when assessing the role of aerosols in the climate system.

URLhttp://dx.doi.org/10.1038/s41467-018-05028-4
DOI10.1038/s41467-018-05028-4
Journal: Nature Communications
Year of Publication: 2018
Volume: 9
Number: 1
Date Published: 07/2018

Aerosol-cloud interactions remain a major uncertainty in climate research. Studies have indicated that model estimates of cloud susceptibility to aerosols frequently exceed satellite estimates, motivating model reformulations to increase agreement. Here we show that conventional ways of using satellite information to estimate susceptibility can serve as only a weak constraint on models because the estimation is sensitive to errors in the retrieval procedures. Using instrument simulators to investigate differences between model and satellite estimates of susceptibilities, we find that low aerosol loading conditions are not well characterized by satellites, but model clouds are sensitive to aerosol perturbations in these conditions. We quantify the observational requirements needed to constrain models, and find that the nighttime lidar measurements of aerosols provide a better characterization of tenuous aerosols. We conclude that observational uncertainties and limitations need to be accounted for when assessing the role of aerosols in the climate system.

DOI: 10.1038/s41467-018-05028-4
Citation:
Ma, P, P Rasch, H Chepfer, D Winker, and S Ghan.  2018.  "Observational Constraint on Cloud Susceptibility Weakened by Aerosol Retrieval Limitations."  Nature Communications 9(1).  https://doi.org/10.1038/s41467-018-05028-4.