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Effects of temporal variability in the environmental factors driving evapotranspiration over grazed pasture during extreme drought

Posted on:2006-07-28Degree:M.AType:Thesis
University:University of Colorado at BoulderCandidate:Alfieri, Joseph GFull Text:PDF
GTID:2453390008958089Subject:Physical geography
Abstract/Summary:
Since drought is the most damaging of weather related natural disasters, it would be prudent to accurately model drought so that its adverse effects can be minimized. To accomplish this, it is necessary to fully understand the effects of drought on the processes linking the land surface to the atmosphere.; This objective was achieved in three phases. In the first phase, a statistical analysis was used to determine the influence of several environmental factors in driving the latent heat flux over time.; The analysis was repeated in the second phase of the research using the partitioned latent heat flux and their respective resistances as the response variable. Soil moisture content was again found to be the major control on both soil evaporation, which was the primary pathway for moisture transfer, and transpiration. Further, a strong sigmoidal relationship between soil moisture and soil resistance and a strong logarithmic relationship between soil moisture and the vegetation resistance was seen.; In the final phase of this research, the relationships developed from the observational data were compared to those used by a number of land surface models including the Noah LSM, Community Land Model, and Simple Biosphere II model.; This research reinforces the importance of accurately describing soil moisture so that the relationships describing the interconnections between the land surface and the atmosphere may be modeled correctly. (Abstract shortened by UMI.)...
Keywords/Search Tags:Drought, Land surface, Model, Soil moisture, Effects
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