Nitrogen oxides (NO x NO NO 2 originating from combustion, lightning and soil, are the main drivers of the tropospheric ozone formation and important precursors of secondary organic aerosols, with consequences for human health, climate and ecosystem Isoprene, the most important biogenic volatile organic compounds (globally, accounts for about half of the BVOC emissions 500 Tg yr 1 Its rapid oxidation in the presence of NO x is a main driver of atmospheric chemistry Detailed and accurate estimations of NO x emissions and a better understanding of isoprene chemis
Mesoscale and submesoscale dynamics and their role on the transport and mixing of ocean biogeochemical tracers have been investigated widely in recent literatures. In general, large circulations and mesoscale eddies control the absolute dispersion of tracers horizontally, while submesoscale motions affect horizontal mixing and, with their strong vertical velocities, control upwelling or subduction processes in the boundary layers, at the ocean surface and near its bottom.
The exponential growth of climate data combined with advances in machine learningoffers new opportunities to understand the climate system and its response to external forcings. This thesis explores and proposes data mining frameworks to reduce the complexityof spatiotemporal climate fields and facilitate analysis and interpretation.As complex as it appears, the dynamics of the climate system is dominated by spatiotemporal patterns and the identification of these patterns and their linkages offers a useful framework for dimensionality reduction.
By the end of this century, the Oceans will markedly change in response to anthropogenic stressors and increasing greenhouse gas emissions. Their circulation and the horizontal and vertical transport of heat, salt, carbon, oxygen and nutrients will be impacted. In response to rising temperatures, stratification will increase in the upper water column, affecting ventilation of the deep ocean and nutrient transport from the deep and nutrient-rich waters to the euphotic layer.
Phosphorus (P) is an essential and limited micronutrient regulating marine primary productivity. Despite the critical roles of marine P cycle in global biogeochemical processes, the mechanisms leading to marine P removal as authigenic apatite are not fully understood. This dissertation investigates the mineralogical and geochemical controls on marine polyphosphate (polyP) transformation and mineralization under laboratory controlled experiments and sediment incubations.
We present a systematic modeling framework for the identification of water vapor plumes in plasma and magnetic field data from spacecraft flybys of Jupiter's moon Europa. In particular, we determine the degree to which different plume configurations can be obscured by the interaction of Jupiter's magnetospheric plasma with Europa's induced dipole field and its global atmosphere. Additionally we constrain the diagnostic potential of ion energy spectrograms to identify signatures of water vapor plumes in the thermal plasma environment of Europa.
Pacific climate and weather extreme events such as heatwaves, drought, and hydrological extremes are dynamically linked large-scale climate variability. This work aims at improving the current understanding of the role of climate coupling within the Pacific system and investigating their changes to anthropogenic forcing.
Particulate matter (PM) is an important component of the atmosphere which affects the planetary energy budget, visibility, and public health. Although atmospheric PM is a complex mixture of inorganic and organic components from a variety of sources, organic aerosols (OA) represent a significant fraction (20-90%) of tropospheric submicron PM. A better understanding of atmospheric organic aerosols is essential to evaluate their impact and develop effective regulations.
Dissolved oxygen (DO) is essential for marine life and biogeochemical cycling. To a first order, DO is determined by the competition between ocean ventilation and biological productivity. Approximately 21% of the atmospheric gases is oxygen, and the waters at the ocean surface are enriched in DO. Ventilation occurs through a suite of physical processes that brings the DO-rich surface waters into the interior ocean.