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dc.contributor.author
Arsenović, Pavle
dc.contributor.supervisor
Thomas, Peter
dc.contributor.supervisor
Rozanov, Eugene
dc.contributor.supervisor
Verronen, Pekka T.
dc.date.accessioned
2018-12-04T10:42:10Z
dc.date.available
2017-11-29T14:12:04Z
dc.date.available
2017-11-29T14:44:08Z
dc.date.available
2017-11-29T14:46:00Z
dc.date.available
2018-12-04T10:42:10Z
dc.date.issued
2017
dc.identifier.uri
http://hdl.handle.net/20.500.11850/215269
dc.identifier.doi
10.3929/ethz-b-000215269
dc.description.abstract
Solar activity has been driving changes in Earth’s climate throughout history. However, since the 1970s, the emissions of greenhouse gases by human activities have become the dominant factor of climate change. Today, global warming is one of the main challenges of the modern society. On centennial time-scales, the solar contribution could still be important for climate. A factor closely related with solar activity is energetic particle precipitation. The impact of energetic particles on atmospheric composition and climate is relatively new area of research. Our aim is: (i) to investigate the influence of solar activity on terrestrial climate during the long term solar changes and (ii) to investigate the impact of energetic particle precipitation, specifically electrons, on atmospheric chemistry and climate. For these purposes we are using SOCOL3-MPIOM chemistry-climate model with interactive ocean. Measurement data from atmospheric monitoring stations shows a significant temperature increase During the early 20th century (1910 – 1940). This period coincided with an increase in both greenhouse gases and solar activity. To determine the main driver for the temperature increase we conducted a comprehensive model study. We considered separately solar UV radiation, solar visible and infrared radiation, energetic particle precipitation, greenhouse gases, ozone precursors, and volcanic eruptions. Globally, our results suggest that the surface warming was mostly induced by increase in concentrations of greenhouse gases. In Europe, however, this temperature increase may have been dominated by an increase of ozone precursors emissions (CO and NOx). The solar radiation in visible and infrared wavebands produced a smaller, yet detectable contribution in temperature trends, especially around Labrador Sea. In 1970s, some human-emitted substances were found to be depleting ozone layer. This was confirmed by observations and an ozone hole over Antarctica was found leading to the prohibition of ozone depleting substances emissions in 1987. Since the ozone layer is the protective shield of Earth against solar UV radiation, a thinning ozone layer is harmful to living beings. At the same time, however, solar UV radiation is responsible for producing ozone. Recent observations of the Sun show that solar activity is gradually decreasing and it has been hypothesized that the Sun might enter a new grand solar minimum in the 21st century. The change in solar radiation might impact the atmospheric chemical composition, temperature and regional climate. In order to investigate the effects of reduced solar activity on these variables, we conducted a model study covering the 21st and 22nd centuries that assumes the Sun will enter a phase of grand solar minimum. Focusing at the end of 21st century, we found that an unusually strong grand solar minimum enhances cooling of the stratosphere and mesosphere due to the presence of high concentrations of the greenhouse gases. We find that the global warming leads to an acceleration of the meridional circulation from tropics to poles and combined with the lower rates of ozone production due to the reduced solar activity, stratospheric ozone concentrations decrease over tropics. Though, based on the ban of ozone depleting substances ozone recovery is expected to happen within the 21st century, we show that total ozone would not recover globally to the levels before the ozone hole as long as grand minimum lasts. This could lead to increase of UV radiation reaching the surface with potential implications for Earth’s ecosystem. Energetic particles constantly bombard the Earth and, as mentioned above, their precipitation into the Earth’s atmosphere is another climate forcing related to solar activity. As part of these particles, energetic electrons can initiate cascades of chemical reactions of which some lead to the production of odd nitrogen oxides and odd hydrogen oxides (NOx and HOx). Due to their low energy (< 30 keV) auroral electrons produce NOx only above the mesosphere while continuously precipitating from magnetosphere. In the polar winter, NOx can descend inside the polar vortex down to the stratosphere where it depletes ozone. Only a recent advance in climate modeling allows implementing this effect of the auroral electrons, which motivated us to analyze their impact on atmospheric chemistry during the Southern Hemispheric winter. Results indicate that around 90% of winter NOx in the polar regions in the upper stratosphere comes from the precipitation of auroral electrons. In accordance with satellite observations, ozone anomalies of around 30% in the mesosphere and around 15% in the stratosphere are found during winters with intense electron precipitation. Electrons of higher energies (middle energy; 30 – 300 keV), precipitate from Earth’s outer radiation belt. They are able to penetrate to lower altitudes than auroral, producing NOx and HOx directly in the mesosphere. Satellite observations of higher energy electron fluxes became available only recently. In order to investigate their impact on atmospheric chemistry and climate, we have included them in our model. We confirm that these electrons, during geomagnetically active periods, significant amounts of NOx and HOx are produced and thus induce ozone depletion. Ozone anomalies in the mesosphere and stratosphere can reach up to 15% and 8%, respectively compared to climatological mean state. Furthermore, by depleting ozone they induce changes in atmospheric temperature and dynamics. Particularly during winters with high electron precipitation, we found anomalous mesospheric warming and stratospheric cooling in both Northern and Southern polar regions. The change in atmospheric temperature and dynamics leads to impact on the surface temperature during boreal winter: cooling around North Pole and warming over continental Asia. Using a single model, we made substantial advances in understanding the influence of solar radiation and energetic electron precipitation on Earth’s chemistry and climate. Nevertheless, we suggest, more models shall include these processes and continue broadening our knowledge about solar influence on climate.
en_US
dc.format
application/pdf
en_US
dc.language.iso
en
en_US
dc.publisher
ETH Zurich
en_US
dc.rights.uri
http://rightsstatements.org/page/InC-NC/1.0/
dc.title
The Influence of Spectral Solar Irradiance and Energetic Particle Precipitation on Climate
en_US
dc.type
Doctoral Thesis
dc.rights.license
In Copyright - Non-Commercial Use Permitted
ethz.size
70 p.
en_US
ethz.identifier.diss
24362
en_US
ethz.publication.place
Zurich
en_US
ethz.publication.status
published
en_US
ethz.leitzahl
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02350 - Dep. Umweltsystemwissenschaften / Dep. of Environmental Systems Science::02717 - Institut für Atmosphäre und Klima / Inst. Atmospheric and Climate Science::03517 - Peter, Thomas / Peter, Thomas
en_US
ethz.leitzahl
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02350 - Dep. Umweltsystemwissenschaften / Dep. of Environmental Systems Science::02717 - Institut für Atmosphäre und Klima / Inst. Atmospheric and Climate Science::03517 - Peter, Thomas / Peter, Thomas
en_US
ethz.leitzahl.certified
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02350 - Dep. Umweltsystemwissenschaften / Dep. of Environmental Systems Science::02717 - Institut für Atmosphäre und Klima / Inst. Atmospheric and Climate Science::03517 - Peter, Thomas / Peter, Thomas
en_US
ethz.leitzahl.certified
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02350 - Dep. Umweltsystemwissenschaften / Dep. of Environmental Systems Science::02717 - Institut für Atmosphäre und Klima / Inst. Atmospheric and Climate Science::03517 - Peter, Thomas / Peter, Thomas
ethz.date.deposited
2017-11-29T14:12:07Z
ethz.source
FORM
ethz.eth
yes
en_US
ethz.availability
Open access
en_US
ethz.date.embargoend
2018-11-29
ethz.rosetta.installDate
2017-11-29T14:44:31Z
ethz.rosetta.lastUpdated
2018-12-04T10:42:25Z
ethz.rosetta.exportRequired
false
ethz.rosetta.versionExported
true
ethz.COinS
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