No description available.

No description available.

No description available.

This thesis describes a multi-channel millimeter wave radiometer control system that will be used for atmospheric water vapor and temperature profile retrievals. The system consists of four subsystems which provide a total of nine frequency channels, a steerable reflector to permit slant-path measurements at different zenith angles, and a host computer for analyzing the data. The nine channels span the water vapor and oxygen absorption lines in the 20 to 60 GHz range. A distributed processing architecture is implemented to control the system. Each of the subsystems employs a signal processor and a microcontroller, which are configurable from the host. The signal processor filters the receiver's output, while the microcontroller oversees the radiometer, accepts data from the signal processor and communicates with the host. The host executes a custom shell that allows it to concurrently accept data from the subsystems, position the reflector and execute user analysis programs.

This thesis describes the first calibration of the Advanced Very High Resolution Radiometer (AVHRR) on the NOAA-11 satellite. Two methods were used to perform the calibration. Both methods relied on calibrated data from a high resolution sensor that passed over the target site at the White Sands Missile Range, New Mexico, on November 21, 1988. The first approach required ground reflectance and atmospheric optical depth data taken during overpass time. The second method relied on historical ground reflectance data and utilized standard atmospheric models. The calibration gains varied widely depending on which set of calibration offsets were used, but the agreement between the gains computed by the two methods was very close: approximately 1% in channel 1 and 2% in channel 2. This close agreement indicates that Method 2, which does not require the complexity and expense of field work, could be a viable option for future calibration efforts.

Microwave satellite imagery is a valuable tool for the observation of mature tropical cyclones. This study examined the application of microwave data to the extratropical transition (ET) process. During ET a tropical cyclone (TC) moves into an area of large gradients in many atmospheric parameters. The data sparse regions in which these gradients exist make the examination of key physical mechanisms responsible for the ET process difficult. The Advanced Microwave Sounding Unit (AMSU) was used to investigate temperature and water vapor gradients. Advanced Microwave Scanning Radiometer was used to examine WV gradients and precipitation intensities. These observations were combined with diagnostic analysis of frontogenesis during the ET process of a TC that re-intensified as an extratropical cyclone and a TC that dissipated. Although the different outcomes of ET were related to differences in coupling between the decaying TC and the midlatitude environment, microwave data were useful for defining specific characteristics that either inhibited or enhanced the coupling of the decaying TC with the midlatitude environment.

Graduation date: 1999 / Best scan available.

A novel method of human presence detection using passive millimeter-wave sensors is presented. The method focuses on detecting a standing human from a moving platform in a cluttered outdoor environment using millimeter-wave radiometry, which has not been attempted before. Ka-band radiometers are used in total power mode as well as correlation mode, which ideally responds well to self-luminous objects such as humans. The intrinsic radiative power from a human is derived as well as the responses of the total power and correlation mode. The application of correlation radiometer theory to the detection of self-luminous objects at close range is presented in the context of human presence detection. Modifications and additions to techniques developed in radio astronomy and remote sensing for close range terrestrial situations are developed and discussed. The correlation radiometer fringe frequency is analyzed in the context of the scanning beam detection system and is estimated using MUSIC and ESPRIT. Detection and classification of humans is accomplished using a Naïve Bayesian classifier. The performance of the classifier is measured using the F1-measure and the receiver operating characteristic. / text

No description available.

No abstract available. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2012.