Thesis (Ph. D.)--University of California, Riverside, 2009. / Includes abstract. Also issued in print. Includes bibliographical references. Available via ProQuest Digital Dissertations.

In order to better quantify the continuous net ecosystem exchange (NEE) at the farm scale, a 24 m high transportable tower-based eddy covariance and profiling system was tested during three field campaigns during the summer and autumn of 2006. The profile measurement system, equipped with a low-cost closed-path infrared gas analyser (LI-840) was designed to measure the carbon dioxide (CO2) storage especially during weak mixing periods under stable conditions. A tethered blimp-based measurement system for the nocturnal boundary layer (NBL) budget technique was deployed on several calm nights to compare with the concentrations and fluxes determined with the profiling system. The profiling system was also installed to determine horizontal and vertical advection. The two-dimensional horizontal positioning of the profile inlets allowed an examination of the CO2 advective gradient in relation to the wind direction. A near-source advection analysis provided parameters for further adjustments of the NEE at the actual farmland.

High frequency turbulent temperature measurements were performed above clipped grass in the lower atmospheric surface layer in conjunction with three-dimensional turbulent velocities. Measurements were also made of turbulent temperature inside a corn canopy and at the canopy top. The 500Hz temperature time series were collected over periods of varying intervals, to a maximum of 24 hours. / The multifractal analysis was performed on several datasets. First scaling properties of the temperature and the velocity fields were examined. Our results suggest that scaling is not observed throughout the entire range but on different regimes. The physically related regimes corresponding to the clipped grass experiment include the inertial subrange, the trend for diurnal peak, and a range between them, all together featuring the existence of the hourly gap. In the canopy experiment, except for the above feature, the effects of the presence of plant objects are also reflected by the presence of two regimes different from those for clipped grass field. / The double trace moment technique was performed on the inertial subrange of the temperature and velocity fields measured over clipped grass to obtain the parameters characterizing the multifractal fields. The variability of the parameters with the atmospheric stability was investigated and no apparent difference between stable and unstable conditions was found. The results reveal that those fields are universal multifractals with the characteristic parameters $ alpha$ near 1.7 and C$ sb1$ ranging from 0.04 to 0.12, implying that the fields can be modeled by a log-Levy process with unbounded singularities. We also found that the critical moment q$ rm sb{s}$ for the multifractal phase transition is close to 4.

Thesis (M.Sc.). / Written for the Dept. of Atmospheric and Oceanic Sciences. Title from title page of PDF (viewed 2008/12/10). Includes bibliographical references.

Thesis (M.S.)--Florida State University, 2004. / Advisor: Dr. Paul Ruscher, Florida State University, College of Arts and Sciences, Dept. of Meteorology. Title and description from dissertation home page (viewed Jan 18, 2005). Includes bibliographical references.

Thesis (Ph.D.)--University of Hamburg, 2005. / Title from PDF file.

Thesis (Ph. D.)--University of Canterbury, 2009. / Typescript (photocopy). Includes bibliographical references (leaves 177-204). Also available via the World Wide Web.

Thesis (M.S.)--Naval Postgraduate School, 1993. / Includes bibliographical references (p. 95-98).

Thesis (Ph. D.)--Ohio State University, 2005. / Title from first page of PDF file. Includes bibliographical references (p. 152-162).

The main motive for studying turbulent flow in an urban environment is to understand the processes governing momentum, heat and mass exchange between the atmosphere and a very inhomogeneous and aerodynamically rough surface. This exchange regulates the microclimate wherein about 40% of the current world population lives. An understanding of its mechanisms is essential for a variety of reasons and applications. The structure of the atmosphere close to this irregular surface is not homogeneous and there is reason for concern that traditional micrometeorological theories are inadequate to describe the turbulent transfer in this environment. The main objective of the present study is to investigate the turbulent transfer mechanism and the applicability of the Monin Obukhov similarity framework in an unstable suburban atmosphere. In addition the first full set of energy balance data including longer term directly-measured sensible and latent heat fluxes is presented. The results suggest that the (co)spectra in respect to shape and location of the peaks are relatively insensitive to surface features. They generally agree well with homogeneous surface layer data with the exceptions of u, T, uw and possibly q which all exhibit slight anomalies which may be attributed to particular surface features. The non-dimensional dissipation functions and most of the integral statistics results follow the trends predicted by similarity theory (i.e. they are a function of stability), however, the magnitudes are often smaller. Analysis of the correlation coefficients shows that under near neutral and slightly unstable conditions the transfers of momentum and heat are most efficient (and enhanced compared to the homogeneous surface layer) whereas the transfer efficiency of moisture is generally least efficient. This results in a dissimilar behaviour of heat and moisture. It is shown that the humidity statistics not only depend on surface boundary conditions but are also influenced by the entire PBL. Observational support in this respect is obtained from a time series analysis of humidity signals which shows the sporadic occurrence of strong, dry downdrafts (under mainly cloudy conditions) which result in positive contributions to the moisture flux. There is evidence that the present observation levels are sometimes within the roughness sub-layer. At around noon and in the early afternoon the Bowen ratio measured using the gradient approach was often larger than the Bowen ratio obtained from directly measured fluxes. This affects the turbulent fluxes derived from the Bowen ratio-energy balance approach. It is suggested that beside the inequality of the transfer efficiencies sampling problems affect the gradient measurements. The average diurnal energy balance is in general agreement with previous summertime observations from the same site. The results indicate that the storage heat flux, obtained as the energy balance residual using directly measured turbulent fluxes, peaks slightly earlier than predicted by the objective hysteresis model. / Arts, Faculty of / Geography, Department of / Graduate