Aerosols significantly affect cloud microphysics and energy budget in different ways. The contribution of the direct, semi-direct, and indirect effects of aerosols on radiation are here investigated over the North Atlantic tropical ocean under different aerosol loadings. The Weather Research and Forecasting Model is used to perform a set of numerical idealized experiments, which are forced with prescribed aerosol profiles. We evaluate the effects of aerosols on modeled shallow clouds and surface radiative budget. The results indicate that large aerosol loadings are associated with enhanced cloudiness and reduced precipitation. While the change in rainfall is mainly due to the larger number of smaller droplets, the change in cloudiness is attributed to the effects of absorbing aerosols, mainly dust particles, which are responsible for a rise of temperature that feeds back onto specific humidity. As in the boundary layer the increase of moisture dominates, the net effect is a higher relative humidity, which favors the formation of thin low non-precipitating clouds. The feedback accounts for a dynamical change in the lower troposphere: shortwave radiation absorption increases temperature at the top of the marine atmospheric boundary-layer and reduces entrainment of warm and dry air, increasing low level moisture content. Despite the overall increase in cloudiness, daytime cloud cover is reduced. The semi-direct effect of aerosols on clouds results in a warming of the surface, opposite to the indirect effect.

Tartaglione, N., Desbiolles, F., del Moral-Mendez, A., Meroni, A., Napoli, A., Borgnino, M., et al. (2024). Low cloud response to aerosol-radiation-cloud interactions: Idealized WRF numerical experiments for EUREC4A project. ATMOSPHERIC SCIENCE LETTERS [10.1002/asl.1208].

Low cloud response to aerosol-radiation-cloud interactions: Idealized WRF numerical experiments for EUREC4A project

Desbiolles F.;Meroni A. N.;Borgnino M.;Pasquero C.
2024

Abstract

Aerosols significantly affect cloud microphysics and energy budget in different ways. The contribution of the direct, semi-direct, and indirect effects of aerosols on radiation are here investigated over the North Atlantic tropical ocean under different aerosol loadings. The Weather Research and Forecasting Model is used to perform a set of numerical idealized experiments, which are forced with prescribed aerosol profiles. We evaluate the effects of aerosols on modeled shallow clouds and surface radiative budget. The results indicate that large aerosol loadings are associated with enhanced cloudiness and reduced precipitation. While the change in rainfall is mainly due to the larger number of smaller droplets, the change in cloudiness is attributed to the effects of absorbing aerosols, mainly dust particles, which are responsible for a rise of temperature that feeds back onto specific humidity. As in the boundary layer the increase of moisture dominates, the net effect is a higher relative humidity, which favors the formation of thin low non-precipitating clouds. The feedback accounts for a dynamical change in the lower troposphere: shortwave radiation absorption increases temperature at the top of the marine atmospheric boundary-layer and reduces entrainment of warm and dry air, increasing low level moisture content. Despite the overall increase in cloudiness, daytime cloud cover is reduced. The semi-direct effect of aerosols on clouds results in a warming of the surface, opposite to the indirect effect.
Articolo in rivista - Articolo scientifico
aerosol-cloud interactions; aerosols; radiation-aerosol-cloud interactions; shallow clouds; Tropical Atlantic;
English
11-gen-2024
2024
e1208
open
Tartaglione, N., Desbiolles, F., del Moral-Mendez, A., Meroni, A., Napoli, A., Borgnino, M., et al. (2024). Low cloud response to aerosol-radiation-cloud interactions: Idealized WRF numerical experiments for EUREC4A project. ATMOSPHERIC SCIENCE LETTERS [10.1002/asl.1208].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/467681
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