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dc.contributor.advisorYang, Zong-liangen
dc.creatorJiang, Xiaoyan, doctor of geological sciencesen
dc.date.accessioned2011-02-09T18:50:22Zen
dc.date.accessioned2011-02-09T18:50:56Zen
dc.date.available2011-02-09T18:50:22Zen
dc.date.available2011-02-09T18:50:56Zen
dc.date.issued2010-12en
dc.date.submittedDecember 2010en
dc.identifier.urihttp://hdl.handle.net/2152/ETD-UT-2010-12-2346en
dc.descriptiontexten
dc.description.abstractLand surface areas, which represent approximately 30% of the Earth’s surface, contribute largely to the complexity of the climate system by exchanging water, energy, momentum, and chemical materials with the overlying atmosphere. Because of the highly heterogeneous nature of the land surface and its rapid transformation due to human activities, future climate projections are less certain on regional scales than for the globe as a whole. The work presented in this dissertation is focused on a better understanding of regional-scale land–atmosphere interactions and their impacts on climate and air quality. Specifically, I concentrate my research on three typical regions in the United States (U.S.): 1) the Central U.S. (representing transition zones between arid and wet climates); 2) the Houston metropolitan region (representing a major urban area); and 3) the eastern U.S. (representing temperate forested regions). These regions are also chosen owing to the consideration of data availability. The first study concerns the roles of vegetation phenology and groundwater dynamics in regulating evapotranspiration and precipitation over the transition zones in summer months. It is found that the warm-season precipitation in the Central U.S. is sensitive to latent heat fluxes controlled by vegetation dynamics. Groundwater enhances the persistence of soil moisture memory from rainy periods to dry periods by transferring water to upper soil layers through capillary forces. Enhancement in soil moisture facilitates vegetation persistence in dry periods, producing more evaporation to the atmosphere and resulting in enhanced precipitation, which then increases soil moisture. The second study compares the impacts of future urbanization and climate change on regional air quality. The results show that the effect of land use change on surface ozone (O3) is comparable to that of climate change, but the details differ across the domain. The third study deals with the formation and distributions of secondary organic aerosols (SOA) — a largely overlooked but potentially important component in the climate system. Under future different climate scenarios, I found that biogenic emissions — an important precursor of SOA — are expected to increase everywhere over the U.S., with the largest increase found in the southeastern U.S. and the northwestern U.S., while changes in SOA do not necessarily follow those in biogenic emissions. Other factors such as partitioning coefficients, atmospheric oxidative capability, primary organic carbon, and anthropogenic emissions also play a role in SOA formation. Direct and indirect impacts from climate change complicate the future SOA formation.en
dc.format.mimetypeapplication/pdfen
dc.language.isoengen
dc.subjectLand–atmosphere interactionsen
dc.subjectVegetationen
dc.subjectGroundwateren
dc.subjectOzoneen
dc.subjectBiogenic emissionsen
dc.subjectSecondary organic aerosolsen
dc.titleRegional-scale land--climate interactions and their impacts on air quality in a changing climateen
dc.date.updated2011-02-09T18:50:56Zen
dc.contributor.committeeMemberDickinson, Robert E.en
dc.contributor.committeeMemberGuenther, Alexen
dc.contributor.committeeMemberJackson, Charlesen
dc.contributor.committeeMemberSharp, Jr., John M.en
dc.contributor.committeeMemberWilson, Clark R.en
dc.description.departmentGeological Sciencesen
dc.type.genrethesisen
thesis.degree.departmentGeological Sciencesen
thesis.degree.disciplineGeological Sciencesen
thesis.degree.grantorUniversity of Texas at Austinen
thesis.degree.levelDoctoralen
thesis.degree.nameDoctor of Philosophyen


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