Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Earth and Planetary Sciences, 1978. / Microfiche copy available in Archives and Science. / Bibliography: leaf 68. / by Nancy Therese Lukitsh. / B.S.

An improved formulation for radar backscatter from a volume of oblate spheroidal raindrops is developed, taking account of the beam elevation angle and the raindrop canting angle. The formulation is in terms of scattering coefficients in a matrix, and can be applied to systems using linear, circular, or elliptical polarization. The general formulation reduces to results previously published in the literature for linear polarization differential reflectivity (Z_DR) and for circular polarization depolarization ratio ( CDR). Analysis of the linear polarization case for a dual-polarization radar which can transmit and receive orthogonal linear polarizations in the horizontal-vertical (HV) planes, and the (±45) degree planes are considered. Results are presented showing the effect raindrop parameters have on Z , and linear polarization ratio (LDR) measured in (HV) and (±45°) planes. Analysis of the circular polarization case for a dual polarization radar which can transmit and receive circular polarizations is also considered. Results show that LDR measured in the (±45°) planes is similar to CDR. The dual-polarized radar development program at VPI&SU was discussed and a detailed design of a new radar data collection system is given. With the theory of dual-polarization radar measurement and the practical implementation of such a radar described within this thesis, a more accurate characterization of the propagation effects along a satellite to earth path can be carried out. / M.S.

Thesis (Ph. D.)--University of Hong Kong, 1984.

Scanning strategies for research and operational applications were developed for meteorological measurements with an experimental PAR, the MWR-05XP. A tornadic storm sampling strategy was developed with a 502.26 ms volumetric update and a resolution of 1.8 Az x 2 El x 150 m range. A sampling strategy for severe thunderstorm clusters was developed with a 10 second volumetric update and a resolution of 1.8 Az x 2 El x 300 m range. An operational weather scanning strategy was developed with an 81 second volumetric update and a resolution of 1.8 Az x 2 El x 150 m range. In general, for the acquisition of weather data, single frequency phased array radars offer only a slight sampling advantage over conventional scanning radars. This research verified that for meteorological sampling with the MWR-05XP, frequency diversity, coupled with electronic elevation scanning, offers a significant sampling advantage over conventional radars. The combination of electronic beam steering and frequency diversity produces a synergistic reduction in sampling time that increases the overall volumetric update rate. This research has also shown that, based on assumptions about the MWR-05XP operating parameters, it is possible to incorporate operational weather scanning into the radar's multifunction capability.

Typescript, etc. / Digitized by Kansas Correctional Industries

This thesis describes the refinements, modifications and additions to a prototype Very High Frequency (VHF) Boundary Layer (BL) Spaced Antenna (SA) radar initially installed at the University of Adelaide's Buckland Park field site in 1997. Previous radar observations of the lowest few kilometres of the atmosphere, in particular the Atmospheric Boundary Layer, have used Ultra-High Frequency (UHF) radars. Unlike VHF radars, UHF radars are extremely sensitive to hydro-meteors and have difficulty in distinguishing clear-air echoes from precipitation returns. The advantages and requirements of using a VHF radar to observe the lowest heights is discussed in conjunction with some of the limitations. The successful operation of the system over long periods has enabled in-depth investigation of the performance of the system in a variety of conditions and locations. Observations were made from as low as 300m and as high as 8 km, dependent upon conditions. Comparisons between the radar and alternative wind measuring devices were carried out and examined. The antenna system of the radar is a critical component which was analysed in depth and subsequently re-designed. Through the use of numerical models and mea- surements, evaluation of different designs was accomplished. Further calibration of the remaining components of the full system has enabled estimations of the absolute received power. Additional parameters which can be derived with a calibrated radar were compared with values obtained by other authors, giving favourable results. Full Correlation Analysis (FCA) is the predominant technique used in this work. A brief discussion of the background theory and parameters which can be measured is described. A simple one-dimensional model was developed and combined with a 'radar backscatter model' to investigate potential sources of errors in the parameters determined using FCA with the VHF Boundary Layer Radar. In particular, underes- timations in the wind velocity were examined. The integration of a Radio Acoustic Sounding System (RASS) to obtain tempera- ture profiles is discussed. The theory of RASS measurements including the limitations and considerations which are required for the VHF BL radar are given. The difficulties encountered trying to implement such a system and the subsequent success using a Stratospheric Tropospheric (ST) Profiler in place of the BL radar is presented. Taken as a whole this thesis shows the success of the VHF BL to obtain mea- surements from as low as 300m. The validation of this prototype radar provides an alternative and, in certain situations, a superior device with which to study the lower troposphere. / Thesis (Ph.D.)--Department of Physics and Mathematical Physics, 2001.

Thesis (Ph. D.)--University of Hong Kong, 1983.

Thesis (Ph. D.)--University of Washington, 2003. / Vita. Includes bibliographical references (p. 100-107).

Thesis (Ph. D.)--University of Washington, 2003. / Vita. Includes bibliographical references (p. 97-106).

Thesis (M.S.)--Brigham Young University. Dept. of Electrical and Computer Engineering, 2003. / Includes bibliographical references (p. 103-104).