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dc.creatorVogel, Gregor Klaus
dc.date.accessioned2012-06-07T22:43:10Z
dc.date.available2012-06-07T22:43:10Z
dc.date.created1995
dc.date.issued1995
dc.identifier.urihttp://hdl.handle.net/1969.1/ETD-TAMU-1995-THESIS-V64
dc.descriptionDue to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to digital@library.tamu.edu, referencing the URI of the item.en
dc.descriptionIncludes bibliographical references.en
dc.descriptionIssued also on microfiche from Lange Micrographics.en
dc.description.abstractRunoff, infiltration, evaporation and transpiration and-at climatic scales-precipitation are hydrologic processes that strongly depend on soil moisture. From a descriptive viewpoint, soil moisture is. characterized by an extremely high degree of heterogeneity over a wide range of scales in both time and space: a complex picture with nested patterns of variability. From a dynamic perspective many factors and processes influence the evolution of soil moisture at different scales: climate, topography, precipitation, geology, pedology, vegetation. In this thesis it is examined whether the apparently orderless spatial structure of soil moisture can be described using a simple statistical approach and the dynamics of soil moisture is investigated through a model. Experimental large scale data of soil moisture, measured from remote sensors, are analyzed under different resolutions. The variance of soil moisture fields is shown to follow a power law decay as function of the area at which the process is observed. The spatial correlation remains unchanged with the scale and follows a power law decay typical of scaling processes. Soil moisture also shows clear scaling properties on its spatial clustering patterns. A well-defined organization of statistical character links scales from the tens of meters to several kilometers. The dynamics of soil moisture in space and time at climatic scales is modeled including its coupling with the atmosphere through energy and mass fluxes. Water balance for the soil and the atmospheric components of the continental hydrologic subsystem as well as energy balance for the atmosphere, including an additive stochastic forcing term, constitute the model's equations. The system evolves in time and shows to be highly organized reaching a noise-induced statistical balance between positive and negative feedbacks. The generated soil moisture fields are analyzed in both time and space showing some of the typical aspects of experimental data: low pass-filtering of rainfall forcing, persistence of droughts and wet periods. Furthermore the model indicates a scaling spectrum of soil moisture for high frequencies, a strong correlation with the atmospheric moisture and precipitation, and positive spatial correlations ranging up to one-fifth of the domain size.en
dc.format.mediumelectronicen
dc.format.mimetypeapplication/pdf
dc.language.isoen_US
dc.publisherTexas A&M University
dc.rightsThis thesis was part of a retrospective digitization project authorized by the Texas A&M University Libraries in 2008. Copyright remains vested with the author(s). It is the user's responsibility to secure permission from the copyright holder(s) for re-use of the work beyond the provision of Fair Use.en
dc.subjectwater resouces engineering.en
dc.subjectMajor water resouces engineering.en
dc.titleThe spatial and temporal organization of soil moistureen
dc.typeThesisen
thesis.degree.disciplinewater resouces engineeringen
thesis.degree.nameM.S.en
thesis.degree.levelMastersen
dc.type.genrethesisen
dc.type.materialtexten
dc.format.digitalOriginreformatted digitalen


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