Abstract. Aerosol heating due to shortwave absorption has
implications for local atmospheric stability and regional dynamics. The
derivation of heating rate profiles from space-based observations is
challenging because it requires the vertical profile of relevant properties
such as the aerosol extinction coefficient and single-scattering albedo
(SSA). In the southeastern Atlantic, this challenge is amplified by the
presence of stratocumulus clouds below the biomass burning plume advected
from Africa, since the cloud properties affect the magnitude of the aerosol
heating aloft, which may in turn lead to changes in the cloud properties and
life cycle. The combination of spaceborne lidar data with passive imagers
shows promise for future derivations of heating rate profiles and curtains,
but new algorithms require careful testing with data from aircraft
experiments where measurements of radiation, aerosol, and cloud parameters
are better colocated and readily available. In this study, we derive heating rate profiles and vertical
cross sections (curtains) from aircraft measurements during the NASA
ObseRvations of Aerosols above CLouds and their intEractionS (ORACLES)
project in the southeastern Atlantic. Spectrally resolved irradiance
measurements and the derived column absorption allow for the separation of
total heating rates into aerosol and gas (primarily water vapor) absorption.
The nine cases we analyzed capture some of the co-variability of heating
rate profiles and their primary drivers, leading to the development of a new
concept: the heating rate efficiency (HRE; the heating rate per unit aerosol
extinction). HRE, which accounts for the overall aerosol loading as well
as vertical distribution of the aerosol layer, varies little with altitude
as opposed to the standard heating rate. The large case-to-case variability
for ORACLES is significantly reduced after converting from heating rate to
HRE, allowing us to quantify its dependence on SSA, cloud albedo, and solar
zenith angle.