Size distributions of sea salt aerosols for marine cloud brightening over the Great Barrier Reef

[Geoengineering News]

https://gfzpublic.gfz-potsdam.de/pubman/faces/ViewItemFullPage.jsp?itemId=item_5018746_1

Authors

Medcraft, Chris¹, Author
Hernandez-Jaramillo, Diana C.¹, Author
Harrison, Luke¹, Author
Braga, Ramon C.¹, Author
Butcherine, Peter¹, Author
Harrison, Daniel P.¹, Author

Conference Paper (2023)

Citation:Medcraft, C., Hernandez-Jaramillo, D. C., Harrison, L., Braga, R. C., Butcherine, P., Harrison, D. P. (2023): Size distributions of sea salt aerosols for marine cloud brightening over the Great Barrier Reef, XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG) (Berlin 2023).

https://doi.org/10.57757/IUGG23-2107

Abstract

Marine cloud brightening (MCB) aims to increase the albedo of low-lying marine clouds by the introduction of additional sea salt aerosol particles (SSA) increasing the population of cloud condensation nuclei which activate to form cloud droplets. The outcomes of this intervention depend on the size and hygroscopicity of the introduced SSA and meteorological conditions. SSA that are too small or too large are both speculated to reduce the magnitude of the desired net albedo increase, or may even reduce albedo. The ideal SSA size distribution is subject to debate however literature suggests dry diameters in the range of 60-1000nm may be effective. Current technologies produce a distribution of SSA particles sizes, rather than the monomodal size originally proposed for MCB. </p><p>We have studied numerous nozzle technologies to continuously, efficiently and effectively produce sufficient quantities of SSA from sea water. Size distributions and production rates of these various nozzle technologies from laboratory data tests will be presented and will be compared to data from a campaign on the southern Great Barrier Reef (Feb-April 2023). Data from this campaign was measured from an aircraft, drones and on the surface from a research ship following another vessel containing the spraying apparatus. The implications for the effectivity of MCB due to changes in size distribution with distance and altitude from the spraying source will discussed. </p><p>&nbsp;</p><p>This work was undertaken as part of the Reef Restoration and Adaptation Program, funded by the partnership between the Australian Governments Reef Trust and the Great Barrier Reef Foundation.

Source: GFZ