SANDCAT

SahAraN Dust and its role in a Changing climATe

Mineral dust particles are transported through the atmosphere from the world’s deserts, deposited over the
oceans, and affect climate and global warming in many different ways. Changing winds and rain determine
how much and how far dust is transported, but the exact relations and feedbacks between dust and climate
are unclear. Dust from the Sahara Desert that blows over the Atlantic Ocean will be collected, its particle size,
shape and composition will be studied, and climate models will reveal how dust and climate affect each other.
This knowledge is fundamental to make more accurate predictions for our future climate.

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Scientific abstract

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.