CLoud-Aerosol-Radiation Interactions and Forcing

The representation of clouds, aerosols and cloud-aerosol-radiation impacts remain the largest uncertainties in climate change, limiting our ability to accurately reconstruct and predict future climate change. The south-east Atlantic is a region where high atmospheric aerosol loadings from biomass burning and semi-permanent stratocumulus cloud are co-located, providing a natural laboratory for studying the full range of aerosol-radiation and aerosol-cloud interactions and their perturbations of the Earth’s radiation budget.

Ground-based observations for CLARIFY have been organised from Oxford.  In 2016, an array of aerosol sampling equipment was set up on Etosha Pan in Northern Namibia. Instruments included a Cimel photometer, Dusttrak aerosol sampler, radiometers, automatic weather stations measuring temperature, wind, pressure etc and a Halo-Photonics Lidar system. In addition, aerosol measurements were made on the Skeleton coast near the Huab river (Cimel, Dusttrak, automatic weather station, passive aerosol samplers). In 2017, observations moved from Etosha to Gobabeb (Lidar, automatic weather station) and were maintained on the Skeleton Coast. An additional automatic weather station and Cimel were set up in the far north on the Kunene river just south of the Angolan border.

CLARIFY is a major consortium programme consisting of 5 UK universities (Exeter, Oxford, Leeds, Manchester and Reading) with project partners from the UK Met Office, European universities and research institutes, the US NSF ONFIRE (ObservatioNs of Fires Impact on the southeast Atlantic Region) and US NASA ORACLES (ObseRvations of Aerosols above CLouds and their interactions).

Richard Washington leads the ground-based instrument deployment in CLARIFY.

CLARIFY cloud and AOD

Mean Aug-Oct aerosol optical depth (colour contours), cloud fraction and aerosol emission estimates. The star shows the position of Walvis Bay (Namibia) and the arc around it is the operating range of the research aircraft.

CLARIFY is principally funded by the Natural Environment Research Council.


Prof Richard Washington (Project Co-I at Oxford)

Prof Philip Stier (Project PI at Oxford)

Prof Jim Haywood (overall Project PI)