Model-Observational Intercomparisons of Aerosol and Cloud Properties during NASA ORACLES

Aerosols, clouds, and their interactions with radiation remain highly uncertain, burdening the reconstruction of past climate and prognosis of future climate change. The prevalent coexistence of African biomass burning aerosols and clouds during Austral winters in the southeast Atlantic presents a natural laboratory for investigating aerosol-cloud-radiation interactions. To gain an understanding of the impacts of biomass burning aerosol on cloud properties and the regional radiation balance requires an integrated modeling and observational plan that spans various spatio-temporal scales. Airborne measurements from three field experiments as part of the ObseRvations of Aerosols above CLouds and their intEractionS (ORACLES) project offer an opportunity to evaluate the representativeness of aerosol and cloud properties from airborne in situ measurements and their limitations due to sparse sampling. This study compares ORACLES airborne observations of aerosol, cloud, and thermodynamic properties against regional chemical transport models and quantifies the spatio-temporal representativeness of airborne measurements by testing the observations against model output. The in situ airborne data are used to quantify multi-spectral satellite retrieval errors, to identify error sources in retrievals, and to improve retrieval algorithms for aerosols above clouds.