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Identifier

000391242

Title

Αριθμητικές προσομοιώσεις ατμοσφαιρικής χημείας και μεταφοράς με έμφαση στην οξειδωτική ικανότητα της τροπόσφαιρας και τα οργανικά αερολύματα

Alternative Title

Numerical simulations of atmospheric chemistry and transport focusing on the oxidizing capacity of the troposphere and organic aerosol

Author

Δασκαλάκης, Νικόλαος Κωνσταντίνου

Thesis advisor

Κανακίδου, Μαρία

Reviewer

Φρουδάκης, Γεώργιος
Στεφάνου, Ευριπίδης

Abstract

The ability of atmospheric composition models to simulate the chemical processes that take place in the atmosphere and the levels of atmospheric pollutants is limited by the understanding of the processes involved and the necessary approximations to parameterize them in the models. Model input data, such as emissions and meteorology, are associated with some of these processes. Emissions are of great interest for environmental sciences, because of their impact on air quality, health and climate, and for the uncertainty they induce to environmental calculations. Therefore, both the development of emission inventories and their impact on the simulations of the chemical composition of the atmosphere are at the center of environmental studies. This study aims to assess and improve the ability of a global 3D chemistry and transport model to simulate atmospheric composition and to apply it for assessing the effectiveness of measures taken to reduce air pollution on our planet in recent decades. First the different processes related to the simulation of organic aerosols in the atmosphere are analyzed and evaluated using simulation results from 31 different chemistry transport and general circulation models. The importance of different parameters and processes is evaluated by model-to-model comparisons but also by model-to-measurements comparisons. Then, the impact of wild fires emissions on pollutant levels, on the lifetimes of pollutants in the troposphere is studied. The differences in the results caused by using different emission inventories and injection heights in the atmosphere are evaluated. Differences in the levels of pollutants in the atmosphere caused by the choice of emission inventory range from -30% to 30% and can reach up to a factor of 7 regionally, especially for aerosols. Emissions from fires also affect the levels of isoprene, a predominantly biogenic tracer, due to the impact of emitted compounds on the oxidizing capacity of the atmosphere. Interestingly, the presence of fires causes a chemical interaction that results to a significant increase in the levels of secondary aerosols produced from isoprene. Finally, the effectiveness of the measures taken to reduce emissions of air pollutants and their precursors, both in the gas and particulate phase, is examined and evaluated. Three different hindcast simulations of the atmospheric composition of the last 30 years were performed using emission scenarios that include or neglect the applied emission reduction regulations. The environmental benefit from the implementation of these measures is calculated by comparisons to past concentrations but also by comparison to simulated air pollution levels in the hypothetical scenario of uncontrolled emissions, both on global and in regional scales. Finally the changes in the seasonal variations (amplitude and timing of maximum) of gases and aerosols is quantified and evaluated. Shifts in seasonality and amplitude changes from season to season are calculated. Keywords: air pollution, atmospheric processes, global, 3D chemistry and transport model, organic aerosols, pollutant emissions.

Language

English

Subject

3-διάστατο μοντέλο μεταφοράς και χημείας

3D chemistry and transport model

Air pollution

Atmospheric processes

Global

Organic aerosols, pollutant emissions.

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