Simulation of Cloud-aerosol Lidar with Orthogonal Polarization (CALIOP) Attenuated Backscatter Profiles Using the Global Model of Aerosol Processes (GLOMAP)

Abstract

To permit the calculation of the radiative effects of atmospheric aerosols, we have linked our aerosol-chemical transport model (CTM-GLOMAP) to a new radiation module (UKCA-RADAER). In order to help assess and improve the accuracy of the radiation code, in particular the height dependence of the predicted scattering, we have developed a module that simulates attenuated backscatter (ABS) profiles that would be measured by the satellite-borne Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) if it were to sample an atmosphere with the same aerosol loading as predicted by the CTM. Initial results of our comparisons of the predicted ABS profiles with actual CALIOP data are encouraging but some differences are noted, particularly in marine boundary layers where the scattering is currently under-predicted and in dust layers where it is often over-predicted. The sources of these differences are being investigated.

Review of Vaughan et al. measurement report "Lidar measurements of stratospheric aerosol following the Raikoke and Ulawun volcanic eruptions"

“…convert the "attenuated backscatter" to a "clean" aerosol backscatter (e.g. as explained in Young et al, 2015;and Antuna Marrero et al, 2020) which then accounts for the attenuation from aerosol and gas phase species in the two-way transmittance. Please add a sentence here to explain what is meant by the "onion-peeling algorithm.…”