zdroj: Strategic Plan for the U.S. Climate Change Science Program
Author Phillipe Rekacewicz, 2003
The employee responsible for the section: Mgr. Peter Huszár, Ph.D.
Composition of atmospheric and chemical processes in the ongoing are particularly important because interaction between the atmosphere and living organisms. The chemical composition of the atmosphere is the result of complex processes, of which the most important are: emissions from surface, chemical reactions, transport and dry and wet deposition.
Emission from the surface: this is the process under, in which the free air release certain gases and aerosol particles. Emissions may have a natural source such as. EMISE already bunch, emissions from fires (if there was such a natural way. after lightning strike), emissions salts in water droplets shattering during intense waves of the oceans, dust emission from the surface when interacting with the flow and eventually biogenic emissions, wherein regards gaseous compounds emitted by plants. Conversely, anthropogenic emissions are due to human activity, in particular the combustion of fossil fuels, transportation (especially automotive), in industrial production, etc..
Substances, which receive air, then these emissions are often subject to chemical transformations, which generates the so-called. secondary compounds. There are a number of, It is worth mentioning for example,. ozone, surface that is not directly emitted, but it is produced in large quantities in the stratosphere and the troposphere. Some substances participating in the reaction, which are also conducted in the liquid phase, often in the presence of water. These reactions are called heterogeneous and often lead to the formation of secondary aerosol particles.
Various substances in the atmosphere may be transported considerable distances, whereby the air flow can contribute to a large extent on the composition of the atmosphere at points, where emissions are not too high.
The lifetime of gaseous, liquid and solid components in the atmosphere is then closed deposit the earth's surface. We distinguish between dry deposition, under which the mean gravitational sedimentation of substances on the surface of the earth, and wet deposition, when it comes to washing cloud and rainwater.
In addition to the aforementioned interaction with the ecosystem composition and chemistry of the atmosphere also important in the radiative balance of the atmosphere. Some gases and aerosol particles can interact with the solar and thermal radiation and cause the absorption, reflection and scattering, or may themselves emit thermal radiation. Hereby changes the radiative balance atmosphere, which results in an altered thermal equilibrium and result in a change of temperature.
In modeling these processes, numerical models used in chemistry of the atmosphere, which is counted in the final time step and provide the time dependence of the three-dimensional distribution of chemical constituents and aerosols. On KMOP MFF UK is now actively used chemical transport model CAMx (www.camx.com), so. Eulerian model, where the calculated change in concentration of substances in the system firmly connected to the earth surface. Other models capable of modeling atmospheric chemistry is used at the department WRF-Chem (http://www.acd.ucar.edu/wrf-chem/).
In order to describe the radiological consequences of chemical processes in the atmosphere is often chosen technique couplování the weather was not climate model. Where weather / climate model provides meteorological conditions for running the model chemistry, which then provides the calculated concentration back to the meteorological model, which contains the algorithm for calculating the influence of radiation and the subsequent temperature change. The department is now used CAMx couple with a regional climate model RegCM.
Models of atmospheric chemistry, or a couple with meteorologickýcmi / climate models can be used for a wide range of purposes from evaluation of the effects of certain emissions (eg. traffic, from certain cities, from agricultural activities, etc.) on the air quality, through modeling of changes in pollutant concentrations due to possible climate change to model climate impacts of emissions changed due to perturbation of the radiation balance of the atmosphere (eg. in the formation of tropospheric ozone, which is a greenhouse gas).
In section Study will find a link to articles, dedicated to the teaching of atmospheric chemistry or her part related. The Department also participates or participated in numerous projects related to atmospheric chemistry research with a large number of publications, as outlined in the Research and publications.
