Impact of climate change on the production and transport of sea salt aerosol on European seas

Joana Soares,Camilla Andersson,Mikhail Sofiev,Jens H Christensen,Camilla Geels,Joakim Langner,Svetlana Tsyro

doi:10.5194/acp-16-13081-2016

Abstract

Abstract. The impact of climate change on sea salt aerosol production, dispersion, and fate over Europe is studied using four offline regional chemistry transport models driven by the climate scenario SRES A1B over two periods: 1990–2009 and 2040–2059. This study is focused mainly on European seas: Baltic, Black, North, and Mediterranean. The differences and similarities between the individual models' predictions of the impact on sea salt emission, concentration, and deposition due to changes in wind gusts and seawater temperature are analysed. The results show that the major driver for the sea salt flux changes will be the seawater temperature, as wind speed is projected to stay nearly the same. There are, however, substantial differences between the model predictions and their sensitivity to changing seawater temperature, which demonstrates substantial lack of current understanding of the sea salt flux predictions. Although seawater salinity changes are not evaluated in this study, sensitivity of sea salt aerosol production to salinity is similarly analysed, showing once more the differences between the different models. An assessment of the impact of sea salt aerosol on the radiative balance is presented.

Highlights

The sea salt aerosol (SSA) affects the Earth radiation budget, atmospheric chemistry, cloud processes, and climate (O’Dowd et al, 1997; IPCC, 2013)
The global ECHAM5/MPIOM model is defined in spectral grid T63, which at mid-latitudes corresponds to a horizontal resolution of ca. 140 × 210 km2
The climate, as downscaled by RCA3, reflects the broad features simulated by the parent general circulation models (GCMs), but from earlier studies with the current setup it is clear that the global ECHAM5/MPIOM

Summary

Introduction

The sea salt aerosol (SSA) affects the Earth radiation budget, atmospheric chemistry, cloud processes, and climate (O’Dowd et al, 1997; IPCC, 2013). Covert et al, 1998; Russell and Heintzenberg, 2000; Bates et al, 2002; Huebert et al, 2003) suggest that for high wind speeds the production of very coarse SSA (with particle diameter, Dp, > 20 mm) increases, contributing to a higher transfer of heat and water vapour from the ocean to the atmosphere (Andreas et al, 1995). These processes have a strong impact on the climate forcing.

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Conclusion