SANDCAT

Global climate change is one of the biggest challenges of our time. Mineral dust plays a key role in the Earth’s climate, through impacts on the atmospheric radiation budget, greenhouse-gas (methane) removal, mineral ballasting, and ocean fertilisation. In return, ongoing climate change has large impacts on dust generation and emission from the sources, (long-distance) transport and deposition of dust. Hence, there are several feedback mechanisms between dust and climate, and the sign and magnitude of their impacts remain unclear. This necessitates timeseries of dust transport and a detailed understanding of deposition pathways, especially over remote areas such as the open ocean, and linking these to climate observations.

The project will exploit a unique transect in the Atlantic Ocean, where mineral dust has been collected for more than a decade with a temporal resolution up to 2 days, down-wind of the world’s largest dust source, the Sahara Desert. This allows studying the effects of a changing climate on the dust cycle on interannual timescales, while novel upgrades to the collectors allow to, for the first time, decipher the various forms of dust deposition (dry deposition by gravitation and wet deposition with precipitation) over the ocean, and to unravel their different impacts on the carbon cycle.

SANDCAT aims to reveal the role of mineral dust in a changing climate, by (1) characterising and quantifying dust transport and exposing differences between wet and dry deposition over the ocean, (2) relating this to current climate variables, and (3) improving model simulations and future climate predictions.

The unique multi-year record with the quantification of dry and wet dust deposition over the Atlantic Ocean, together with a thorough particle characterisation and the implementation in state-of-the-art climate models, will lead SANDCAT to determine the two-way interactions between dust and climate, ultimately contributing to improved climate projections.