Thesis (Ph. D.)--University of Texas at Austin, 2005. / Vita. Includes bibliographical references.

Thesis (M.Sc.)--York University, 2007. Graduate Programme in Geography. / Typescript. Includes bibliographical references (leaves 157-163). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:MR38844

An evaluation of the global water storage contribution to the Chandler wobble has never been undertaken because: (1) the hydrological data necessary for the reconstruction of an extended monthly time series have not been available; and (2) the water storage contribution has traditionally been regarded as relatively unimportant because of its minor role in the excitation of the annual wobble. However, a crude approximation of the global water storage series is possible using worldwide records of monthly precipitation and temperature, accumulating precipitation at individual locations whenever temperatures are at 0° Celsius or below. Comparison of this modeled series with a previous estimate of the annual component of the global water balance, and with the observed monthly polar motion series, indicates good agreement with the former, and a significant correlation with the latter near the Chandler frequency. / text

Thesis (Ph.D.)--Pennsylvania State University, 2008. / Mode of access: World Wide Web.

Thesis (M.S.)--University of North Texas, Dec., 2008. / Title from title page display. Includes bibliographical references.

Thesis (Ph.D.)--The Chinese University of Hong Kong, 2005. / Advisers: Chen Yongqin, Lam Kin-che. Includes bibliographical references (p. 174-190)

Not available / text

Thesis (Ph. D.)--University of Texas at Austin, 2003. / Vita. Includes bibliographical references. Available also from UMI Company.

Meteorological and environmental (i.e. soil water content) data measured from semiarid watersheds (Lucky Hills and Kendall) during the summer rainy and winter periods were used to study the interrelationships between variables, and to evaluate the effects of variables on the daily estimation of actual evapotranspiration (AET). The relationship between AET and potential evapotranspiration (PET) as a function of an environmental factor was the major consideration of this research. The relationship between AET and PET as a function of soil water content as suggested by Thornthwaite-Mather, Morton and Priestley-Taylor was studied to determine its applicability to the study area. Furthermore, multiple linear regression (MLR) analysis was employed to evaluate the order of importance of the meteorological and soil water factors involved. Finally, the information gained was used for MLR model development. The results of MLR analysis showed that the combined effects of available energy, soil water content and wind speed were responsible for 77 % of the observed variations in AET at Lucky Hills watershed and 70 % at Kendall watershed during the summer rainy period. The analyses also indicated that the combined effects of available energy, vapor pressure deficit and wind speed were responsible for 70 % of the observed variations in AET at Lucky Hills watershed and 72 % at Kendall watershed during the winter period. However, the test results of three different approaches, using the relationships between AET and PET as a function of soil water content indicated some inadequacy. The low correlation between PET, AET, and soil moisture conditions raised some doubt concerning the validity of methods developed elsewhere, and indicated the effects of energy availability on the relationship between PET, AET, and soil water content regardless of the soil water condition. In contrast, agreement between observed AET and estimated AET from MLR models during the summer rainy and winter periods at both watersheds indicated that MLR models can give reasonable estimates of AET, at least under the climatic conditions in which the formulae were developed.

Bank storage is defined as a volume of water that periodically infiltrates a river's banks during increases in stream stage. It is a potentially critical variable for accurately modeling the water budget in semi-arid riparian systems, but is particularly difficult to assess and quantify. It is especially essential for understanding ground-water/surface-water interactions. In collaboration with other projects, a field-scale vadose monitoring effort took place in the San Pedro Riparian National Conservation Area (SPRNCA), Arizona. The San Pedro River flows north from Mexico into the United States, and SPRNCA is a 60 km stretch of U.S.-protected ecosystem north of the border. In addition to a progressive climate of ecological conservation, hydrological research that leads to an improved understanding of the water budget will ultimately improve the prospects for improved water policy decisions. Soil moisture, stream stage, and soil tension data were collected for over 8 consecutive months in both 1997 and 1998, and the data were used as input into a software program called HYDRUS-2D (§imiinek et al. 1996), which models two-dimensional, variably saturated flow. Field-collected data and subsequent modeling efforts suggest that the effects of bank storage were estimated to contribute approximately 8.5% of the river's total flow for 147 days in 1997. Accordingly, bank storage and its effects should be considered in future water-balance simulations of stream-aquifer interaction, and of the San Pedro River in particular. In addition, model estimates of root water uptake match favorably with other estimates of evapotranspiration in the cottonwood-willow forest gallery of the SPRNCA.