First generation outdoor marine cloud brightening trial increases aerosol concentration at cloud base height
Diana Carolina Hernandez Jaramillo, Luke Harrison, Grace Gunner, Andrew McGrath, Wolfgang Junkermann, Wolfgang Lieff, Jorg Hacker, Daniel Rosenfeld, Brendan Kelaher and Daniel P. Harrison
Environmental research letters, Vol.20(5), pp.1-12
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Abstract
marine cloud brightening plume dispersion airborne measurements particle number concentration
Regional scale marine cloud brightening (MCB) has been proposed as a novel climate intervention to reduce the impact of global warming and associated marine heatwaves on the Great Barrier Reef. The concept relies on artificially generated sea spray aerosols (SSA) at the ocean surface and their transport in sufficient quantities to low-level maritime clouds. A portion of the SSA that reaches cloud height can act as additional cloud condensation nuclei and modify cloud microphysical properties, potentially reducing the amount of solar radiation reaching the sea surface. Although modelling data supports the MCB concept, field experiments demonstrating the dispersion of artificially produced SSA to clouds have not been previously reported. Here, we show that within a field of low-level trade wind cumulus-type clouds, an aerosol plume generated at the sea surface on board a research vessel was rapidly advected to cloud base height. Aircraft measurements conducted during two different sampling strategies, detected the aerosol plume from the vessel's sea water atomisation system just below cloud bases at 700–900 m altitudes. For an estimated surface level aerosol production rate of 4 × 1014 s−1, aerosol concentrations at cloud base were detected with peak number concentrations of up to ∼1 × 103 cm−3. Although such production rates of aerosol particles are orders of magnitude less than what is envisioned for any practical implementation of MCB, our results indicate that cloud perturbation experiments should now be possible using surface-produced SSA.
Details
Title
First generation outdoor marine cloud brightening trial increases aerosol concentration at cloud base height
Creators
Diana Carolina Hernandez Jaramillo - Southern Cross University
Luke Harrison - The University of Sydney
Grace Gunner - ARA
Andrew McGrath - ARA
Wolfgang Junkermann - ARA
Wolfgang Lieff - ARA
Jorg Hacker - ARA
Daniel Rosenfeld - The Hebrew University of Jerusalem
Brendan Kelaher - Southern Cross University
Daniel P. Harrison - Southern Cross University
Publication Details
Environmental research letters, Vol.20(5), pp.1-12
Publisher
IOP Publishing Ltd
Grant note
The Reef Restoration and Adaptation Program is funded by the partnership between the Australian Government’s Reef Trust and the Great Barrier Reef Foundation.