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Quantifying climatological precipitation and soil moisture as well as interannual variability and trends requires extensive observation. This work focuses on the analysis of available precipitation and soil moisture data and the development of new ways to estimate these quantities. Precipitation and soil moisture characteristics are highly dependent on the spatial and temporal scales. We begin at the point scale, examining hourly precipitation and soil moisture at individual gauges. First, we focus on the Walnut Gulch Experimental Watershed (WGEW), a 150 km² area in southern Arizona. The watershed has been measuring rainfall since 1956 with a very high density network of approximately 0.6 gauges per km². Additionally, there are 19 soil moisture probes at 5 cm depth with data starting in 2002. In order to extend the measurement period, we have developed a water balance model which estimates monsoon season (Jul-Sep) soil moisture using only precipitation for input, and calibrated so that the modeled soil moisture fits best with the soil moisture measured by each of the 19 probes from 2002-2012. This observationally constrained soil moisture is highly correlated with the collocated probes (R=0.88), and extends the measurement period from 10 to 56 years and the number of gauges from 19 to 88. Then, we focus on the spatiotemporal variability within the watershed and the ability to estimate area averaged quantities. Spatially averaged precipitation and observationally constrained soil moisture from the 88 gauges is then used to evaluate various gridded datasets. We find that gauge-based precipitation products perform best followed by reanalyses and then satellite-based products. Coupled Model Intercomparison Project Phase 5 (CMIP5) models perform the worst and overestimate cold season precipitation while offsetting the monsoon peak precipitation forward or backward by a month. Satellite-based soil moisture is the best followed by land data assimilation systems and reanalyses. We show that while WGEW is small compared to the grid size of many of the evaluated products, unlike scaling from point to area, the effect of scaling from smaller to larger area is small. Finally, we focus on global precipitation. Global monthly gauge based precipitation data has become widely available in recent years and is necessary for analyzing the climatological and anomaly precipitation fields as well as for calibrating and evaluating other gridded products such as satellite-based and modeled precipitation. However, frequency and intensity of precipitation are also important in the partitioning of water and energy fluxes. Therefore, because daily and sub-daily observed precipitation is limited to recent years, the number of raining days per month (N) is needed. We show that the only currently available long-term N product, developed by the Climate Research Unit (CRU), is deficient in certain areas, particularly where CRU gauge data is sparse. We then develop a new global 110-year N product, which shows significant improvement over CRU using three regional daily precipitation products with far more gauges than are used in CRU.

The promoters of the large groundwater developments implemented in the 1970's paid little attention to the effects of pumping on soil moisture. A field study, conducted in 1979 in the Tern Area of the Shropshire Groundwater Scheme, revealed that significant quantities of the available moisture could be removed from the root zone of vegetation when drawdown of shallow watertables occurred. Arguments to this effect, supported by the field study evidence, were successfully presented at the Shropshire Groundwater Scheme public inquiry. The aim of this study has been to expand the work which was undertaken in connection with the Shropshire Groundwater Scheme, and to develop a method whereby the effects of groundwater pumping on vegetation can be assessed, and hence the impacts minimised. Two concepts, the critical height and the soil sensitivity depth, formulated during the initial work are at the core of the Environmental Impact Assessment method whose development is described. A programme of laboratory experiments on soil columns is described, as is the derivation of relationships for determining critical heights and field capacity moisture profiles. These relationships are subsequently employed in evaluating the effects of groundwater drawdown. In employing the environmental assessment technique, digitised maps of relevant features of the Tern Area are combined to produce composite maps delineating the extent of the areas which are potentially sensitive to groundwater drawdown. A series of crop yield/moisture loss functions are then employed to estimate the impact of simulated pumping events on the agricultural community of the Tern Area. Finally, guidelines, based on experience gained through evaluation of the Tern Area case study, are presented for use in the design of soil moisture monitoring systems and in the siting of boreholes. In addition recommendations are made for development of the EIA technique, and further research needs are identified.

"The presence of moisture can lead to serious damage in Hot Mix Asphalt mixes and failures of HMA pavements. This is of an even greater concern for Warm Mix Asphalt (WMA) due to the use of much lower production temperatures which may not be high enough to completely dry the aggregates. In this Maine DOT study, the use of fracture energy parameters was evaluated to determine the influence of incomplete drying of mixes on their mechanical properties. Fracture energy based parameters (ER: energy ratio; RER: ratio of energy ratio) were determined from the following indirect tensile testing on mixes with fully and partially dried aggregates, some of which were subjected to moisture conditioning: Resilient modulus (Mr), creep compliance, and indirect tensile strength (ITS) strength at 5oC. The results indicate that: i. resilient modulus, creep compliance, and indirect tensile strength were all affected by the presence of moisture in mixes; ii. the trend and degree of influence by moisture for the different mechanical parameters are different; iii. The moisture conditioning process has caused larger decreases in resilient modulus and ITS values than incomplete drying of aggregates; however, the same moisture conditioning process has caused much larger decreases in modulus and ITS in asphalt mixes prepared with incompletely dried aggregates than the counterparts prepared with fully dried aggregates; and iv. fracture energy-based parameters (ER and RER) appear to be more distinctive moisture effect/damage indicators than the other parameters. "

Typescript. / Digitized by Kansas Correctional Industries

Typescript (photocopy) / xx, 251 leaves, [6] leaves of plates : ill. (part col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Soil Science, 1982

The application of the widely used Penrnan-Monteith evapotranspiration equation to hybrid poplar trees is impossible without a valid surface resistance. The increase in applications of drip-irrigated hybrid poplar trees for wood chip stock and veneer production, as well as bioremediation, constitutes a need for estimating the evapotranspiration of these trees. To the author's knowledge, there are no published estimates of surface resistance for poplar trees. Six years of weekly soil moisture content for drip-irrigated, hybrid poplar trees were used in a water balance to compute evapotranspiration. The weekly data were adjusted with reference evapotranspiration data to compute a daily evapotranspiration. Only data that represent fully leaved hybrid poplars are used in this study and the data were screened for the effects of drainage. Additional parameters applied in this study include solar radiation, temperature, wind speed and relative humidity taken at a nearby AGRIMET Weather Station. The results of this study indicate that surface resistance values cannot be described as a function of meteorological data within the constraints of the current experiment design. The graph of poplar evapotranspiration versus surface resistance shows that for a given evapotranspiration there can be multiple rs values. This scatter is the influence of parameters other than rs within the Penman-Monteith model. The use of an instrument to directly measure the surface resistance is recommended in further studies. / Graduation date: 2000

Sandwich composites with polymer foam core are currently used in load-bearing components in buildings and naval structures due to their high strength to weight and stiffness to weight ratios, excellent thermal insulation, and ease of manufacturing. During their service time, sandwich composites are exposed to various external mechanical and hygro-thermal stimuli. It is known that the constituent properties of the sandwich composites are greatly influenced by the temperature and moisture fields. For example extreme temperature changes and humid environmental conditions can significantly degrade the stiffness and strength of the polymer foam core. This study analyzes the effect of moisture diffusion on the deformation of viscoelastic sandwich composites, which are composed of orthotropic fiber-reinforced laminated skins and viscoelastic polymeric foam core. It is assumed that the elastic and time-dependent (transient) moduli at any particular location in the foam core depend on the moisture concentration at that location. Sequentially coupled analyses of moisture diffusion and deformation are performed to predict overall performance of the studied viscoelastic sandwich systems. A time and moisture dependent constitutive model is used for the polymer foam core. A time-integration algorithm is developed to link this constitutive model to finite element (FE) analyses framework. The overall time-dependent responses of the sandwich composites subject to moisture diffusion are analyzed using 2D plane strain and 3D continuum elements. A 23% increase in the transverse deformation of the viscoelastic sandwich beam is observed due to the moisture degradation. Experimental data and analytical models available in the literature are used to verify the results obtained from the FE code. Parametric studies on the effects of different diffusivity ratios of skin and core materials on stress, strain and displacement fields have been analyzed. At the initial times the effect of moisture on the field variables is found to be most pronounced in the case with the highest diffusivity ratio. Contributions of moisture dependent elastic and the time-dependent moduli to the overall stress, strain and displacement field have been studied. The structural analysis of the sandwich composite under combined moisture diffusion and mechanical loading for two kinds of problems using FE method is performed to complete the study.

In this research, a systematic and multi-disciplinary study was conducted to understand the fundamental science of moisture-induced degradation of interfacial adhesion. The research is comprised of both experimental and modeling components of analysis and consists of four primary components. First, the moisture transport behavior within underfill adhesives is experimentally characterized and incorporated into a finite element model to depict the moisture ingress and interfacial moisture concentration for each respective level of moisture preconditioning. Second, the effect of moisture on the variation of the underfill elastic modulus is demonstrated and the physical mechanisms for the change identified. Third, the aggregate effect of moisture on the interfacial fracture toughness of underfill to both copper and FR-4 board substrates is determined. This includes the primary effect of moisture being physically present at the interface and the secondary effect of moisture changing the elastic modulus of the adhesive when absorbed. Last, the recovery of both the elastic modulus and interfacial fracture toughness from moisture preconditioning is assessed with reversible and irreversible components identified. Using adsorption theory in conjunction with fracture mechanics, an analytical model is developed that predicts the loss in interfacial fracture toughness as a function of moisture content. The model incorporates key parameters relevant to the problem of moisture in epoxy joints identified from the experimental portion of this research, including the interfacial hydrophobicity, epoxy nanopore density, saturation concentration, and density of water. This research results in a comprehensive understanding of the primary mechanisms responsible for the interfacial degradation due to the presence of moisture. The experimental results obtained through this research provide definitive data for the electronics industry to use in their product design, failure analysis, and reliability modeling. The predictive model developed in this research provides a useful tool for developing new adhesives, innovative surface treatment methods, and effective protection methodologies for enhancing interfacial adhesion.

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