Daytime aerosol optical depth above low-level clouds is similar to that in adjacent clear skies at the same heights: airborne observation above the southeast Atlantic Journal Article uri icon



  • Abstract. To help satellite retrieval of aerosols and studies of their radiative; effects, we demonstrate that daytime aerosol optical depth over low-level; clouds is similar to that in neighboring clear skies at the same heights.; Based on recent airborne lidar and sun photometer observations above the; southeast Atlantic, the mean aerosol optical depth (AOD) difference at 532 nm is between 0 and; −0.01, when comparing the cloudy and clear sides, each up to 20 km wide, of; cloud edges. The difference is not statistically significant according to a; paired t test. Systematic differences in the wavelength dependence of AOD; and in situ single scattering albedo are also minuscule. These results hold; regardless of the vertical distance between cloud top and aerosol layer; bottom. AOD aggregated over ∼2∘ grid boxes for each of; September 2016, August 2017 and October 2018 also shows little correlation; with the presence of low-level clouds. We posit that a satellite retrieval; artifact is entirely responsible for a previous finding of generally smaller; AOD over clouds (Chung et al., 2016), at least for the region and time of; our study. Our results also suggest that the same values can be assumed for; the intensive properties of free-tropospheric biomass-burning aerosol; regardless of whether clouds are present below.;

publication date

  • October 2, 2020

Date in CU Experts

  • March 2, 2021 11:11 AM

Full Author List

  • Shinozuka Y; Kacenelenbogen MS; Burton SP; Howell SG; Zuidema P; Ferrare RA; LeBlanc SE; Pistone K; Broccardo S; Redemann J

author count

  • 17

Other Profiles

Electronic International Standard Serial Number (EISSN)

  • 1680-7324

Additional Document Info

start page

  • 11275

end page

  • 11285


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