The regional atmospheric model Consortium for Small-scale Modeling (COSMO) coupled to the Multi-Scale Chemistry Aerosol Transport model (MUSCAT) is extended in this work to represent aerosol–cloud ...interactions. Previously, only one-way interactions (scavenging of aerosol and in-cloud chemistry) and aerosol–radiation interactions were included in this model. The new version allows for a microphysical aerosol effect on clouds. For this, we use the optional two-moment cloud microphysical scheme in COSMO and the online-computed aerosol information for cloud condensation nuclei concentrations (Cccn), replacing the constant Cccn profile. In the radiation scheme, we have implemented a droplet-size-dependent cloud optical depth, allowing now for aerosol–cloud–radiation interactions. To evaluate the models with satellite data, the Cloud Feedback Model Intercomparison Project Observation Simulator Package (COSP) has been implemented. A case study has been carried out to understand the effects of the modifications, where the modified modeling system is applied over the European domain with a horizontal resolution of 0.25° × 0.25°. To reduce the complexity in aerosol–cloud interactions, only warm-phase clouds are considered. We found that the online-coupled aerosol introduces significant changes for some cloud microphysical properties. The cloud effective radius shows an increase of 9.5 %, and the cloud droplet number concentration is reduced by 21.5 %.
Modelling mineral dust emissions Laurent, B; Marticorena, B; Bergametti, G ...
IOP conference series. Earth and environmental science,
03/2009, Letnik:
7, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The biogeochemical cycle of mineral dust is of major interest to understand climatic changes. Moreover, these particles can also cause risks for human health and societal activities in regions in the ...neighbourhoods of arid and semi-arid source areas of dust emission. To estimate and forecast atmospheric dust concentrations and their impacts, the correct description of the spatial and temporal variability of dust emission occurrences and intensities is a prerequisite. The explicit dust emission models provide a physical description of the main processes involved in dust production. They allow describing the spatio-temporal variability of the non-linear phenomenon of dust production if their input parameters (surface and soil features, surface winds) are accurately described. The recent developments, the current limits of these emission models, and some of their applications using relevant surface, soil and meteorological databases to simulate dust emissions are presented here.
North Africa is the world’s largest source of dust, a large part of which is transported across the Atlantic to the Caribbean and beyond where it can impact radiation and clouds. Many aspects of this ...transport and its climate effects remain speculative. The Saharan Aerosol Long-Range Transport and Aerosol-Cloud-Interaction Experiment (SALTRACE; www.pa.op.dlr.de/saltrace) linked ground-based and airborne measurements with remote sensing and modeling techniques to address these issues in a program that took place in 2013/14. Specific objectives were to 1) characterize the chemical, microphysical, and optical properties of dust in the Caribbean, 2) quantify the impact of physical and chemical changes (“aging”) on the radiation budget and cloud microphysical processes, 3) investigate the meteorological context of transatlantic dust transport, and 4) assess the roles of removal processes during transport. SALTRACE was a German-led initiative involving scientists from Europe, Cabo Verde, the Caribbean, and the United States. The Falcon research aircraft of the Deutsches Zentrum für Luft- und Raumfahrt (DLR), equipped with a comprehensive aerosol and wind lidar payload, played a central role. Several major dust outbreaks were studied with 86 h of flight time under different conditions, making it by far the most extensive investigation on long-range transported dust ever made. This article presents an overview of SALTRACE and highlights selected results including data from transatlantic flights in coherent air masses separated by more than 4,000-km distance that enabled measurements of transport effects on dust properties. SALTRACE will improve our knowledge on the role of mineral dust in the climate system and provide data for studies on dust interactions with clouds, radiation, and health.
SUPPLEMENT Weinzierl, Bernadett; Ansmann, A.; Prospero, J. M. ...
Bulletin of the American Meteorological Society,
07/2017, Letnik:
98, Številka:
7
Journal Article
PDF
