This discussion paper is a preprint. A revision of this manuscript was accepted for the journal Geoscientific Model Development (GMD) and is expected to appear here in due course.
The aerosol-climate model ECHAM6.3-HAM2.3: Aerosol evaluation
Received: 20 Sep 2018 – Accepted for review: 10 Oct 2018 – Discussion started: 11 Oct 2018
Abstract. We introduce and evaluate the 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 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.
We describe a new version of the aerosol-climate model ECHAM-HAM and show tests of the performance of model by comparing different aspects of the aerosol distribution with different datasets. The updated version of the HAM aerosol model contains improved descriptions of aerosol processes including updated emission fields and cloud processes. While there are regional deviations between model and observations, the model performs well overall.
We describe a new version of the aerosol-climate model ECHAM-HAM and show tests of the ...