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Your search keyword '"Ferrachat, Sylvaine"' showing total 4 results
Start Over Author "Ferrachat, Sylvaine" Journal geoscientific model development
4 results on '"Ferrachat, Sylvaine"'

1. The global aerosol–climate model ECHAM6.3–HAM2.3 – Part 1: Aerosol evaluation

Author

Tegen, Ina, Neubauer, David, Ferrachat, Sylvaine, Siegenthaler-Le Drian, Colombe, Bey, Isabelle, Schutgens, Nick, Stier, Philip, Watson-Parris, Duncan, Stanelle, Tanja, Schmidt, Hauke, Rast, Sebastian, Kokkola, Harri, Schultz, Martin, Schroeder, Sabine, Daskalakis, Nikos, Barthel, Stefan, Heinold, Bernd, and Lohmann, Ulrike

Subjects
ddc:550, respiratory system, complex mixtures
Abstract

We introduce and evaluate aerosol simulations with the global aerosol–climate model ECHAM6.3–HAM2.3, which is the aerosol component of the fully coupled aerosol–chemistry–climate model ECHAM–HAMMOZ. Both the host atmospheric climate model ECHAM6.3 and the aerosol model HAM2.3 were updated from previous versions. The updated version of the HAM aerosol model contains improved parameterizations of aerosol processes such as cloud activation, as well as updated emission fields for anthropogenic aerosol species and modifications in the online computation of sea salt and mineral dust aerosol emissions. Aerosol results from nudged and free-running simulations for the 10-year period 2003 to 2012 are compared to various measurements of aerosol properties. While there are regional deviations between the model and observations, the model performs well overall in terms of aerosol optical thickness, but may underestimate coarse-mode aerosol concentrations to some extent so that the modeled particles are smaller than indicated by the observations. Sulfate aerosol measurements in the US and Europe are reproduced well by the model, while carbonaceous aerosol species are biased low. Both mineral dust and sea salt aerosol concentrations are improved compared to previous versions of ECHAM–HAM. The evaluation of the simulated aerosol distributions serves as a basis for the suitability of the model for simulating aerosol–climate interactions in a changing climate.

Published
2019
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2. SALSA2.0: The sectional aerosol module of the aerosol–chemistry–climate model ECHAM6.3.0-HAM2.3-MOZ1.0

Author

Kokkola, Harri, primary, Kühn, Thomas, additional, Laakso, Anton, additional, Bergman, Tommi, additional, Lehtinen, Kari E. J., additional, Mielonen, Tero, additional, Arola, Antti, additional, Stadtler, Scarlet, additional, Korhonen, Hannele, additional, Ferrachat, Sylvaine, additional, Lohmann, Ulrike, additional, Neubauer, David, additional, Tegen, Ina, additional, Siegenthaler-Le Drian, Colombe, additional, Schultz, Martin G., additional, Bey, Isabelle, additional, Stier, Philip, additional, Daskalakis, Nikos, additional, Heald, Colette L., additional, and Romakkaniemi, Sami, additional

Published
2018
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3. The chemistry–climate model ECHAM6.3-HAM2.3-MOZ1.0

Author

Schultz, Martin G., primary, Stadtler, Scarlet, additional, Schröder, Sabine, additional, Taraborrelli, Domenico, additional, Franco, Bruno, additional, Krefting, Jonathan, additional, Henrot, Alexandra, additional, Ferrachat, Sylvaine, additional, Lohmann, Ulrike, additional, Neubauer, David, additional, Siegenthaler-Le Drian, Colombe, additional, Wahl, Sebastian, additional, Kokkola, Harri, additional, Kühn, Thomas, additional, Rast, Sebastian, additional, Schmidt, Hauke, additional, Stier, Philip, additional, Kinnison, Doug, additional, Tyndall, Geoffrey S., additional, Orlando, John J., additional, and Wespes, Catherine, additional

Published
2018
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4. The global aerosol–climate model ECHAM6.3–HAM2.3 – Part 2: Cloud evaluation, aerosol radiative forcing, and climate sensitivity.

Author

Neubauer, David, Ferrachat, Sylvaine, Siegenthaler-Le Drian, Colombe, Stier, Philip, Partridge, Daniel G., Tegen, Ina, Bey, Isabelle, Stanelle, Tanja, Kokkola, Harri, and Lohmann, Ulrike

Subjects
*CLIMATE sensitivity, *RADIATIVE forcing, *STRATOCUMULUS clouds, *CLOUD droplets, *ICING (Meteorology), *CLOUDINESS, *SNOWFLAKES
Abstract

The global aerosol–climate model ECHAM6.3–HAM2.3 (E63H23) as well as the previous model versions ECHAM5.5–HAM2.0 (E55H20) and ECHAM6.1–HAM2.2 (E61H22) are evaluated using global observational datasets for clouds and precipitation. In E63H23, the amount of low clouds, the liquid and ice water path, and cloud radiative effects are more realistic than in previous model versions. E63H23 has a more physically based aerosol activation scheme, improvements in the cloud cover scheme, changes in the detrainment of convective clouds, changes in the sticking efficiency for the accretion of ice crystals by snow, consistent ice crystal shapes throughout the model, and changes in mixed-phase freezing; an inconsistency in ice crystal number concentration (ICNC) in cirrus clouds was also removed. Common biases in ECHAM and in E63H23 (and in previous ECHAM–HAM versions) are a cloud amount in stratocumulus regions that is too low and deep convective clouds over the Atlantic and Pacific oceans that form too close to the continents (while tropical land precipitation is underestimated). There are indications that ICNCs are overestimated in E63H23. Since clouds are important for effective radiative forcing due to aerosol–radiation and aerosol–cloud interactions (ERF ari+aci) and equilibrium climate sensitivity (ECS), differences in ERF ari+aci and ECS between the model versions were also analyzed. ERF ari+aci is weaker in E63H23 (-1.0 W m -2) than in E61H22 (-1.2 W m -2) (or E55H20; -1.1 W m -2). This is caused by the weaker shortwave ERF ari+aci (a new aerosol activation scheme and sea salt emission parameterization in E63H23, more realistic simulation of cloud water) overcompensating for the weaker longwave ERF ari+aci (removal of an inconsistency in ICNC in cirrus clouds in E61H22). The decrease in ECS in E63H23 (2.5 K) compared to E61H22 (2.8 K) is due to changes in the entrainment rate for shallow convection (affecting the cloud amount feedback) and a stronger cloud phase feedback. Experiments with minimum cloud droplet number concentrations (CDNCmin) of 40 cm -3 or 10 cm -3 show that a higher value of CDNCmin reduces ERF ari+aci as well as ECS in E63H23. [ABSTRACT FROM AUTHOR]

Published
2019
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