This thesis discusses methods to measure several atmospheric parameters related to turbulence. Techniques used by two different scintillometers based on weak turbulence theory are discussed along with a method to estimate the inner scale developed by Hill. The theory and minimization algorithm used to infer the atmospheric parameters are discussed. The main focus is on the analysis and collection of experimental data with a three-aperture receiver system. Intensity fluctuations from a CW laser source are collected over a 1km path with three different receiving apertures. The scintillation index is found for each receiving aperture and recently developed theory for all regimes of optical turbulence is used to infer three atmospheric parameters, Cn2, l0, and L0. The transverse wind speed is also calculated from the experimental data using a cross-correlation technique. Parallel to the three-aperture data collection is a commercial scintillometer unit which reports Cn2 and crosswind speed. There is also a weather station positioned at the receiver side which provides point measurements for temperature and wind speed. The Cn2 measurement obtained from the commercial scintillometer is used to infer l0, L0, and the scintillation index. Those values are then compared to the inferred atmospheric parameters from the experimental data. Hill's method is used as an estimate to l0 based upon path-averaged wind speed and is compared to the inferred l0 values. The optimal aperture sizes required for three-aperture data collection are presented. In closing, the technique for measuring crosswind speed is discussed along with the ideal aperture size and separation distance for data collection. Suggestions are offered for future experimentation.

<p> A gabbroic intrusion within the Goulburn group of sediments near the west margin of Bathurst trench was studied and mapped using a TV-1 scintillometer. Petrographic examination of the sill was carried out and geochemical whole rock and trace element data were obtained using X.R.F. methods. </p> <p> The 1308 Lake sill was injected conformably between the Western River (argillite/greywacke) and Burnside River (pink quartzite) units of the Goulburn group of sediments. The sill subsequently underwent minor fractional crystallization and differentiation. Generally the sill exhibits poor phase layering, but can be divided into six basic units. </p> 1) Upper Chilled Margin Gabbro 2) Leuco-Micro-Syenite Lens 3) Diabasic Gabbro 4) Pyroxene Granophyre 5) Diabasic Gabbro 6) Basal Sheared Chilled Margin Gabbro These units are evident in this section and are distinguishable both modally and texturally. In most cases, variations in the chemistry and norms reflect the units mapped in the field. Comparisons have been drawn and theories incorporated from other gabbroic intrusions to help explain some features of the 1308 Lake sill. </p> / Thesis / Bachelor of Arts (BA)

Master of Science / Department of Agronomy / Jay Ham / The exchange of water, carbon, and energy between grasslands and the atmosphere is an important biogeochemical pathway affecting ecosystem productivity and sustainability. The eddy covariance (EC) technique directly measures this mass and energy exchange. However, questions remain regarding the accuracy of EC-derived H[subscript]2O and CO[subscript]2 fluxes in landscapes with irregular topography and variable vegetation. These concerns stem from the "energy balance (EB) closure problem" (i.e., measured energy in does not equal measured energy out). My main objectives were to examine EB closure at two topographical positions within an annually burned tallgrass prairie watershed and to examine the effect of landscape position and woody encroachment on carbon and water exchanges. In tallgrass prairie, 14 km south of Manhattan, KS, USA, EC towers were deployed at three sites in 2007 and 2008. One upland and lowland tower were within an annually burned watershed dominated by C[subscript]4 grasses. Another lowland tower was deployed in a separate quadrennial-burned watershed where significant woody vegetation occupied the tower's sampling area. All towers measured EB components (net radiation, R[subscript]n; soil heat flux, G; sensible heat flux, H; and latent heat flux, [lambda]E). In the annually burned watershed, landscape position had little effect on G, H, and R[subscript]n with differences [less than] 2% between sites. However lowland [lambda]E was 8% higher, owing to larger plant biomass/leaf area and greater soil moisture. Energy balance closure (i.e., [[lambda]E + H] / [R[subscript]n - G]) was 0.87 and 0.90 at the upland and lowland sites, respectively. A nearby large-aperture scintillometer provided good validation of EC-derived H in 2007. Data suggested that underestimates of [lambda]E may have accounted for the closure problem; sample calculations showed that increasing [lambda]E by 17% would have resulted in near prefect closure. Data from this study suggests that EB closure does not strongly correlate with topographical position; however these data raise questions regarding accuracy of the [lambda]E term. Mass exchange analysis shows that the prairie carbon cycle is highly dependent on burning. The lowland and upland annually burned sites saw carbon gains of 281 to 444 g C m[superscript]-[superscript]2 yr[superscript]-[superscript]1 before burning with the shrub lowland showing the least (e.g. 159 and 172 g C m[superscript]-[superscript]2 yr[superscript]-[superscript]1). After the prescribed burn, the upland and lowland sites remained slight carbon sinks (68 to 191 g C m[superscript]-[superscript]2 yr[superscript]-[superscript]1), whereas the unburned shrub site was a carbon sink in 2007 (159 g C m[superscript]-[superscript]2 yr[superscript]-[superscript]1, because no carbon loss was incurred via burning) and a large carbon source in 2008 when it was burned the following year (336 g C m[superscript]-[superscript]2 yr[superscript]-[superscript]1 loss). Evapotranspiration (ET) was highest at the shrub lowland where greater soil moisture and abundance of deep-rooted C[subscript]3 shrub vegetation allowed greater uptake and loss of water.