Dissertations / Theses: 'Microwave sensing'

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Strawbridge, Fiona. "Passive microwave remote sensing of vegetation." Thesis, University of Bristol, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.242948.

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Au, Wai Chung 1966. "Computational electomagnetics in microwave remote sensing." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/11645.

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Sreerekha, T. R. "Impact of clouds on microwave remote sensing." Berlin Logos-Verl, 2005. http://d-nb.info/979728304/34.

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Remund, Quinn P. "Multisensor microwave remote sensing in the cryosphere /." Diss., CLICK HERE for online access, 2000. http://contentdm.lib.byu.edu/ETD/image/etd7.pdf.

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Tian, Xiaoyi. "Microwave Photonic Sensing Based on Optical Microresonators." Thesis, The University of Sydney, 2022. https://hdl.handle.net/2123/29545.

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Optical microresonators (OMRs) have been widely applied in various sensing applications. However, the sensing performances of conventional OMR-based sensors are subject to resonance parameters and fabrication accuracy and are further restricted by the interrogation scheme used. Recently, microwave photonic (MWP) techniques have been used to realize high-speed and high-resolution OMR-based sensors. So far, those MWP schemes are either still fabrication dependent or only applicable to specific uses, and rare attention has been paid to achieving multi-parameter sensing that is indispensable in real-life applications. The thesis proposes novel OMR-based MWP sensing schemes with improved sensing performances. Based on the MWP sideband processing technique, a new MWP interrogation scheme, which features a high resolution regardless of the OMR parameters and fabrication imperfections, is proposed and demonstrated in the sensing of temperature, humidity, and magnetic field, respectively, with high sensitivity and high resolution, where an automatic correction mechanism is added to compensate for resonance lineshape variation automatically. Next, the high-resolution MWP sensing scheme is extended to cascaded OMRs to enable multi-parameter sensing capability. The simultaneous high-resolution MWP sensing of temperature and humidity with two cascaded OMRs is demonstrated. Lastly, machine learning (ML) and deep learning (DL) techniques are applied to MWP sensing to reduce the complexity further. The temperature-insensitive MWP humidity sensor is first achieved with the support vector regression. Then, a new MWP multi-parameter sensing paradigm with the least requirement on the OMR structure is proposed by incorporating DL to process the raw interrogation results directly. The simultaneous MWP sensing of temperature and humidity with a single optical resonance using the convolutional neural tangent kernel is demonstrated.

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Remund, Quinn P. "Multisensor Microwave Remote Sensing in the Cryosphere." BYU ScholarsArchive, 2003. https://scholarsarchive.byu.edu/etd/72.

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Because the earth's cryosphere influences global weather patterns and climate, the scientific community has had great interest in monitoring this important region. Microwave remote sensing has proven to be a useful tool in estimating sea and glacial ice surface characteristics with both scatterometers and radiometers exhibiting high sensitivity to important ice properties. This dissertation presents an array of studies focused on extracting key surface features from multisensor microwave data sets. First, several enhanced resolution image reconstruction issues are addressed. Among these are the optimization of the scatterometer image reconstruction (SIR) algorithm for NASA scatterometer (NSCAT) data, an analysis of Ku-band azimuthal modulation in Antarctica, and inter-sensor European Remote Sensing Satellite (ERS) calibration. Next, various methods for the removal of atmospheric distortions in image reconstruction of passive radiometer observations are considered. An automated algorithm is proposed which determines the spatial extent of sea ice in the Arctic and Antarctic regions from NSCAT data. A multisensor iterative sea ice statistical classification method which adapts to the temporally varying signatures of ice types is developed. The sea ice extent and classification algorithms are adopted for current SeaWinds scatterometer data sets. Finally, the automated inversion of large-scale forward electromagnetic scattering of models is considered and used to study the temporal evolution of the scattering properties of polar sea ice.

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Xiao, Renmeng. "Passive microwave snow mapping in Quebec." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq29810.pdf.

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English, Stephen James. "Remote sensing of meteorological parameters by microwave radiometry." Thesis, University of Oxford, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302777.

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Yu, Guoyu. "Fibre Bragg gratings for microwave photonics and sensing." Thesis, Aston University, 2002. http://publications.aston.ac.uk/7996/.

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This thesis presents details on the fabrication of microwave transversal filters using fibre Bragg grating arrays and the building of fibre Bragg grating based magnetic-field sensors. Some theoretical background about fibre Bragg gratings, photosensitivity, fibre Bragg grating sensors and filters are presented. Fibre Bragg grating sensors in other industrial applications are highlighted. Some sensing principles are also introduced. Experimental work is carried out to demonstrate a magnetic-field sensor using an established fibre Bragg grating strain sensor. System performance and trade-off are discussed. The most important part of this thesis is on the fabrication of photonic transversal filter using fibre Bragg grating arrays. In order to improve the filter performance, a novel tap multiplexing structure is presented. Further improving approaches such as apodisation are also investigated. The basis of nonrecirculating filter, some structure and performance are introduced.

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Yang, Wenjian. "Microwave Photonics and Sensing based on Silicon Photonics." Thesis, University of Sydney, 2020. https://hdl.handle.net/2123/23482.

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Chip scale photonic integrated circuits can provide important new functions in communications, signal processing and sensing. Recent research on microwave photonics (MWPs) and integrated optical sensors using the silicon photonic devices has opened up new opportunities for signal processing and sensing applications. MWPs brings together the world of microwave engineering and optoelectronics, which provides solutions for processing high frequency microwave signals. It has attracted significant interest in many different areas including communications, sensors, radar systems and defence applications. The use of photonic integrated circuit enhances functionalities and flexibilities as well as enabling a reduction of size and weight for MWP applications. The high integratablity of the photonic circuit not only boosts the filtering, time delay and phase shifting functionalities, but also enables the sensing applications in the nano-scale range. Integrated sensors are under high demand in many environmental chemical and biomedical applications. The mass fabricated integrated sensor provides opportunities for multi-functional sensor array with minimized volume. The research work presented in this thesis aims to investigate silicon photonics applications in MWP signal processing and different sensing circumstances. Firstly, the MWP filter based on the SOI microring resonator with phase compensation method is demonstrated. In addition, instantaneous frequency measurement based on frequency to time mapping is presented. Then, a novel integrated optical sensor system based on SOI add drop microring resonator structure is presented. The MWP techniques for high performance sensing application is explored. Lastly, to address the multi-functionality of silicon photonics based sensor, an application of integrated ultrasound optical sensor is demonstrated. It is expected the work provided in this thesis can assist in the emergence of real-world silicon photonic applications. (1992 out of 2000 characters)

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Piles, Guillem Maria. "Multiscale soil moisture retrievals from microwave remote sensing observations." Doctoral thesis, Universitat Politècnica de Catalunya, 2010. http://hdl.handle.net/10803/77910.

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La humedad del suelo es la variable que regula los intercambios de agua, energía, y carbono entre la tierra y la atmósfera. Mediciones precisas de humedad son necesarias para una gestión sostenible de los recursos hídricos, para mejorar las predicciones meteorológicas y climáticas, y para la detección y monitorización de sequías e inundaciones. Esta tesis se centra en la medición de la humedad superficial de la Tierra desde el espacio, a escalas global y regional. Estudios teóricos y experimentales han demostrado que la teledetección pasiva de microondas en banda L es optima para la medición de humedad del suelo, debido a que la atmósfera es transparente a estas frecuencias, y a la relación directa de la emisividad del suelo con su contenido de agua. Sin embargo, el uso de la teledetección pasiva en banda L ha sido cuestionado en las últimas décadas, pues para conseguir la resolución temporal y espacial requeridas, un radiómetro convencional necesitaría una gran antena rotatoria, difícil de implementar en un satélite. Actualmente, hay tres principales propuestas para abordar este problema: (i) el uso de un radiómetro de apertura sintética, que es la solución implementada en la misión Soil Moisture and Ocean Salinity (SMOS) de la ESA, en órbita desde noviembre del 2009; (ii) el uso de un radiómetro ligero de grandes dimensiones y un rádar operando en banda L, que es la solución que ha adoptado la misión Soil Moisture Active Passive (SMAP) de la NASA, con lanzamiento previsto en 2014; (iii) el desarrollo de técnicas de desagregación de píxel que permitan mejorar la resolución espacial de las observaciones. La primera parte de la tesis se centra en el estudio del algoritmo de recuperación de humedad del suelo a partir de datos SMOS, que es esencial para obtener estimaciones de humedad con alta precisión. Se analizan diferentes configuraciones con datos simulados, considerando (i) la opción de añadir información a priori de los parámetros que dominan la emisión del suelo en banda L —humedad, rugosidad, temperatura del suelo, albedo y opacidad de la vegetación— con diferentes incertidumbres asociadas, y (ii) el uso de la polarización vertical y horizontal por separado, o del primer parámetro de Stokes. Se propone una configuración de recuperación de humedad óptima para SMOS. La resolución espacial de los radiómetros de SMOS y SMAP (40-50 km) es adecuada para aplicaciones globales, pero limita la aplicación de los datos en estudios regionales, donde se requiere una resolución de 1-10 km. La segunda parte de esta tesis contiene tres novedosas propuestas de mejora de resolución espacial de estos datos: • Se ha desarrollado un algoritmo basado en la deconvolución de los datos SMOS que permite mejorar la resolución espacial de las medidas. Los resultados de su aplicación a datos simulados y a datos obtenidos con un radiómetro aerotransportado muestran que es posible mejorar el producto de resolución espacial y resolución radiométrica de los datos. • Se presenta un algoritmo para mejorar la resolución espacial de las estimaciones de humedad de SMOS utilizando datos MODIS en el visible/infrarrojo. Los resultados de su aplicación a algunas de las primeras imágenes de SMOS indican que la variabilidad espacial de la humedad del suelo se puede capturar a 32, 16 y 8 km. • Un algoritmo basado en detección de cambios para combinar los datos del radiómetro y el rádar de SMAP en un producto de humedad a 10 km ha sido desarrollado y validado utilizando datos simulados y datos experimentales aerotransportados. Este trabajo se ha desarrollado en el marco de las actividades preparatorias de SMOS y SMAP, los dos primeros satélites dedicados a la monitorización de la variación temporal y espacial de la humedad de la Tierra. Los resultados presentados contribuyen a la obtención de estimaciones de humedad del suelo con la precisión y la resolución espacial necesarias para un mejor conocimiento del ciclo del agua y una mejor gestión de los recursos hídricos.
Soil moisture is a key state variable of the Earth's system; it is the main variable that links the Earth's water, energy and carbon cycles. Accurate observations of the Earth's changing soil moisture are needed to achieve sustainable land and water management, and to enhance weather and climate forecasting skill, flood prediction and drought monitoring. This Thesis focuses on measuring the Earth's surface soil moisture from space at global and regional scales. Theoretical and experimental studies have proven that L-band passive remote sensing is optimal for soil moisture sensing due to its all-weather capabilities and the direct relationship between soil emissivity and soil water content under most vegetation covers. However, achieving a temporal and spatial resolution that could satisfy land applications has been a challenge to passive microwave remote sensing in the last decades, since real aperture radiometers would need a large rotating antenna, which is difficult to implement on a spacecraft. Currently, there are three main approaches to solving this problem: (i) the use of an L-band synthetic aperture radiometer, which is the solution implemented in the ESA Soil Moisture and Ocean Salinity (SMOS) mission, launched in November 2009; (ii) the use of a large lightweight radiometer and a radar operating at L-band, which is the solution adopted by the NASA Soil Moisture Active Passive (SMAP) mission, scheduled for launch in 2014; (iii) the development of pixel disaggregation techniques that could enhance the spatial resolution of the radiometric observations. The first part of this work focuses on the analysis of the SMOS soil moisture inversion algorithm, which is crucial to retrieve accurate soil moisture estimations from SMOS measurements. Different retrieval configurations have been examined using simulated SMOS data, considering (i) the option of adding a priori information from parameters dominating the land emission at L-band —soil moisture, roughness, and temperature, vegetation albedo and opacity— with different associated uncertainties and (ii) the use of vertical and horizontal polarizations separately, or the first Stokes parameter. An optimal retrieval configuration for SMOS is suggested. The spatial resolution of SMOS and SMAP radiometers (~ 40-50 km) is adequate for global applications, but is a limiting factor to its application in regional studies, where a resolution of 1-10 km is needed. The second part of this Thesis contains three novel downscaling approaches for SMOS and SMAP: • A deconvolution scheme for the improvement of the spatial resolution of SMOS observations has been developed, and results of its application to simulated SMOS data and airborne field experimental data show that it is feasible to improve the product of the spatial resolution and the radiometric sensitivity of the observations by 49% over land pixels and by 30% over sea pixels. • A downscaling algorithm for improving the spatial resolution of SMOS-derived soil moisture estimates using higher resolution MODIS visible/infrared data is presented. Results of its application to some of the first SMOS images show the spatial variability of SMOS-derived soil moisture observations is effectively captured at the spatial resolutions of 32, 16, and 8 km. • A change detection approach for combining SMAP radar and radiometer observations into a 10 km soil moisture product has been developed and validated using SMAP-like observations and airborne field experimental data. This work has been developed within the preparatory activities of SMOS and SMAP, the two first-ever satellites dedicated to monitoring the temporal and spatial variation on the Earth's soil moisture. The results presented contribute to get the most out of these vital observations, that will further our understanding of the Earth's water cycle, and will lead to a better water resources management.

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Stephen, Haroon. "Microwave Remote Sensing of Saharan Ergs and Amazon Vegetation." Diss., CLICK HERE for online access, 2006. http://contentdm.lib.byu.edu/ETD/image/etd1461.pdf.

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Cheng, Qiao. "Compressive sensing for microwave and millimeter-wave array imaging." Thesis, Queen Mary, University of London, 2018. http://qmro.qmul.ac.uk/xmlui/handle/123456789/31704.

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Compressive Sensing (CS) is a recently proposed signal processing technique that has already found many applications in microwave and millimeter-wave imaging. CS theory guarantees that sparse or compressible signals can be recovered from far fewer measure- ments than those were traditionally thought necessary. This property coincides with the goal of personnel surveillance imaging whose priority is to reduce the scanning time as much as possible. Therefore, this thesis investigates the implementation of CS techniques in personnel surveillance imaging systems with different array configurations. The first key contribution is the comparative study of CS methods in a switched array imaging system. Specific attention has been paid to situations where the array element spacing does not satisfy the Nyquist criterion due to physical limitations. CS methods are divided into the Fourier transform based CS (FT-CS) method that relies on conventional FT and the direct CS (D-CS) method that directly utilizes classic CS formulations. The performance of the two CS methods is compared with the conventional FT method in terms of resolution, computational complexity, robustness to noise and under-sampling. Particularly, the resolving power of the two CS methods is studied under various cir- cumstances. Both numerical and experimental results demonstrate the superiority of CS methods. The FT-CS and D-CS methods are complementary techniques that can be used together for optimized efficiency and image reconstruction. The second contribution is a novel 3-D compressive phased array imaging algorithm based on a more general forward model that takes antenna factors into consideration. Imaging results in both range and cross-range dimensions show better performance than the conventional FT method. Furthermore, suggestions on how to design the sensing con- figurations for better CS reconstruction results are provided based on coherence analysis. This work further considers the near-field imaging with a near-field focusing technique integrated into the CS framework. Simulation results show better robustness against noise and interfering targets from the background. The third contribution presents the effects of array configurations on the performance of the D-CS method. Compressive MIMO array imaging is first derived and demonstrated with a cross-shaped MIMO array. The switched array, MIMO array and phased array are then investigated together under the compressive imaging framework. All three methods have similar resolution due to the same effective aperture. As an alternative scheme for the switched array, the MIMO array is able to achieve comparable performance with far fewer antenna elements. While all three array configurations are capable of imaging with sub-Nyquist element spacing, the phased array is more sensitive to this element spacing factor. Nevertheless, the phased array configuration achieves the best robustness against noise at the cost of higher computational complexity. The final contribution is the design of a novel low-cost beam-steering imaging system using a flat Luneburg lens. The idea is to use a switched array at the focal plane of the Luneburg lens to control the beam-steering. By sequentially exciting each element, the lens forms directive beams to scan the region of interest. The adoption of CS for image reconstruction enables high resolution and also data under-sampling. Numerical simulations based on mechanically scanned data are conducted to verify the proposed imaging system.

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Ramnath, Vinod. "Estimation of soil moisture using active microwave remote sensing." Master's thesis, Mississippi State : Mississippi State University, 2003.

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Piepmeier, Jeffrey R. "Remote sensing of ocean wind vectors by passive microwave polarimetry." Diss., Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/15027.

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Kong, Fanqi. "Dual-frequency Optoelectronic Oscillator and its Application in Transverse Load Sensing." Thesis, Université d'Ottawa / University of Ottawa, 2014. http://hdl.handle.net/10393/31537.

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In this thesis, dual-frequency optoelectronic oscillators (OEOs) and their applications to transverse load sensing are studied. Two configurations of dual-frequency OEOs are proposed and investigated. In the first configuration, a polarization-maintaining phase-shifted fiber Bragg grating (PM-PSFBG) is employed in the OEO loop to the generation of two oscillating frequencies. The beat between the two oscillating frequencies is a function of the load applied to the PM-PSFBG, which is used in transverse load sensing. To avoid the frequency measurement ambiguity, a second configuration is proposed by coupling a dual-wavelength fiber laser to the dual-frequency OEO. A single tone microwave signal with the frequency determined by the birefringence of the grating is generated in the OEO and is fed into the fiber ring laser to injection lock the dual wavelengths. The sensitivity and the resolution are measured to be 9.73 GHz/(N/mm) and 2.06×10-4 N/mm, respectively. The high stability of the single-tone microwave signal permits accurate measurement, while the frequency interrogation allows an ultra-high speed demodulation.

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Lau, Chung-Lun. "Microwave limb sounder instrument noise analysis and calibration." Thesis, Heriot-Watt University, 1995. http://hdl.handle.net/10399/760.

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Hong, Liang. "INTER-SATELLITE MICROWAVE RADIOMETER CALIBRATION." Doctoral diss., University of Central Florida, 2008. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3323.

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The removal of systematic brightness temperature (Tb) biases is necessary when producing decadal passive microwave data sets for weather and climate research. It is crucial to achieve Tb measurement consistency among all satellites in a constellation as well as to maintain sustained calibration accuracy over the lifetime of each satellite sensor. In-orbit inter-satellite radiometric calibration techniques provide a long term, group-wise solution; however, since radiometers operate at different frequencies and viewing angles, Tb normalizations are made before making intermediate comparisons of their near-simultaneous measurements. In this dissertation, a new approach is investigated to perform these normalizations from one satellite's measurements to another. It uses Taylor's series expansion around a source frequency to predict Tb of a desired frequency. The relationship between Tb's and frequencies are derived from simulations using an oceanic Radiative Transfer Model (RTM) over a wide variety of environmental conditions. The original RTM is built on oceanic radiative transfer theory. Refinements are made to the model by modifying and tuning algorithms for calculating sea surface emission, atmospheric emission and attenuations. Validations were performed with collocated WindSat measurements. This radiometric calibration approach is applied to establish an absolute brightness temperature reference using near-simultaneous pair-wise comparisons between a non-sun synchronous radiometer and two sun-synchronous polar-orbiting radiometers: the Tropical Rain Measurement Mission (TRMM) Microwave Imager (TMI), WindSat (on Coriolis) and Advanced Microwave Scanning Radiometer (AMSR) on Advanced Earth Observing System –II (ADEOSII), respectively. Collocated measurements between WindSat and TMI as well as between AMSR and TMI, within selected 10 weeks in 2003 for each pair, are collected, filtered and applied in the cross calibration. AMSR is calibrated to WindSat using TMI as a transfer standard. Accuracy prediction and error source analysis are discussed along with calibration results. This inter-satellite radiometric calibration approach provides technical support for NASA's Global Precipitation Mission which relies on a constellation of cooperative satellites with a variety of microwave radiometers to make global rainfall measurements.
Ph.D.
School of Electrical Engineering and Computer Science
Engineering and Computer Science
Electrical Engineering PhD

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Li, Li. "Microwave remote sensing techniques for vapor, liquid and ice parameters /." Thesis, Connect to this title online; UW restricted, 1995. http://hdl.handle.net/1773/6070.

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Skofronick, Gail Mari. "Iterative nonlinear statistical retrievals of precipitation from simulated spaceborne multispectral passive microwave observations." Diss., Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/13398.

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Das, Narendra N. "Soil moisture modeling and scaling using passive microwave remote sensing." Texas A&M University, 2005. http://hdl.handle.net/1969.1/4881.

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Soil moisture in the shallow subsurface is a primary hydrologic state governing land-atmosphere interaction at various scales. The primary objectives of this study are to model soil moisture in the root zone in a distributed manner and determine scaling properties of surface soil moisture using passive microwave remote sensing. The study was divided into two parts. For the first study, a root zone soil moisture assessment tool (SMAT) was developed in the ArcGIS platform by fully integrating a one-dimensional vadose zone hydrology model (HYDRUS-ET) with an ensemble Kalman filter (EnKF) data assimilation capability. The tool was tested with dataset from the Southern Great Plain 1997 (SGP97) hydrology remote sensing experiment. Results demonstrated that SMAT displayed a reasonable capability to generate soil moisture distribution at the desired resolution at various depths of the root zone in Little Washita watershed during the SGP97 hydrology remote sensing experiment. To improve the model performance, several outstanding issues need to be addressed in the future by: including "effective" hydraulic parameters across spatial scales; implementing subsurface soil properties data bases using direct and indirect methods; incorporating appropriate hydrologic processes across spatial scales; accounting uncertainties in forcing data; and preserving interactions for spatially correlated pixels. The second study focused on spatial scaling properties of the Polarimetric Scanning Radiometer (PSR)-based remotely sensed surface soil moisture fields in a region with high row crop agriculture. A wavelet based multi-resolution technique was used to decompose the soil moisture fields into larger-scale average soil moisture fields and fluctuations in horizontal, diagonal and vertical directions at various resolutions. The specific objective was to relate soil moisture variability at the scale of the PSR footprint (800 m X 800 m) to larger scale average soil moisture field variability. We also investigated the scaling characteristics of fluctuation fields among various resolutions. The spatial structure of soil moisture exhibited linearity in the log-log dependency of the variance versus scale-factor, up to a scale factor of -2.6 (6100 m X 6100 m) irrespective of wet and dry conditions, whereas dry fields reflect nonlinear (multi-scaling) behavior at larger scale-factors.

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Cadeddu, Maria Paola. "Remote sensing of the atmosphere by ground-based microwave radiometry." Thesis, Heriot-Watt University, 2001. http://hdl.handle.net/10399/461.

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Standley, Andy. "Passive microwave remote sensing of snow cover from satellite data." Thesis, University of Bristol, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.265475.

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Miller, Michael W. (Michael William). "A spaceborne microwave radiometer design for ocean wind remote sensing." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/39388.

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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1996.
Includes bibliographical references (leaves 60-61).
by Michael W. Miller.
M.Eng.

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Konings, Alexandra Georges. "Microwave remote sensing of water in the soil - plant system." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/101833.

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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Civil and Environmental Engineering, 2015.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 171-191).
Remotely sensed measurements made by radars or radiometers in the low microwave frequency range are sensitive to soil moisture, soil roughness, and vegetation water content. Measurements made at multiple polarizations can be used to determine additional ancillary parameters alongside the primary variable of interest. However, if an attempt is made to retrieve too many parameters from too few measurements, the resulting retrievals will contain high levels of noise. In this thesis, I introduce a framework to determine an upper bound on the number of geophysical parameters that can be retrieved from remotely sensed measurements such as those made by microwave instruments. The principles behind this framework, as well as the framework itself, are then applied to derive two new ecohydrological variables: a) soil moisture profiles across much of the root-zone and b) vegetation optical depth, which is proportional to vegetation water content. For P-band observations, it is shown that soil moisture variations with depth must be accounted for to prevent large forward modeling - and thus retrieval - errors. A Tikhonov regularization approach is then introduced to allow retrieval of soil moisture in several profile layers by using statistics on the expected co-variation between soil moisture at different depths. The algorithm is tested using observations from the NASA Airborne Microwave Observatory of Subcanopy and Subsurface (AirMOSS) Mission over the Harvard Forest in Western Massachusetts. Additionally, at L-band, a multi-temporal algorithm is introduced to determine vegetation optical depth (VOD) alongside soil moisture. The multi-temporal approach used reduces the chance of compensating errors between the two retrieved parameters (soil moisture and vegetation optical depth), caused by small amounts of measurement noise. In several dry tropical ecosystems, the resulting VOD dataset is shown to have opposite temporal behavior to coincident cross-polarized backscattering coefficients, an active microwave indicator of vegetation water content and scattering. This possibly shows dry season bud-break or enduring litter presence in these regions. Lastly, cross-polarized backscattering coefficients are used to test the hypothesis that vegetation water refilling slows down under drought even at the ecosystem scale. Evidence for this hypothesis is only found in the driest location tested.
by Alexandra Georges Konings.
Ph. D.

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Xu, Zhiqian. "Theoretical models for microwave remote sensing of forests and vegetation." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/11010.

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Diaz, Carlos Luis Perez. "Development of a Microwave - Remote Sensing Based Snow Depth Product." Thesis, The City College of New York, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10745516.

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Snow is a key component of the Earth’s energy balance, climate, environment, and a major source of freshwater in many regions. Seasonal and perennial snow cover affect up to 50% of the Northern Hemisphere landmass, which accounts for vast regions of the Earth that influence climate, culture, and commerce significantly. Information on snow properties such as snow cover, depth, and wetness is important for making hydrological forecasts, monitoring climate change, weather prediction, and issuing snowmelt runoff, flash flood, and avalanche warnings. Hence, adequate knowledge of the areal extent of snow and its properties is essential for hydrologists, water resources managers, and decision-makers.

The use of infrared (IR) and microwave (MW) remote sensing (RS) has demonstrated the capability of estimating the presence of snow cover and snowpack properties with accuracy. However, there are few publicly accessible, operational RS-based snow depth products, and these only provide the depth of recently accumulated dry snow because retrievals lose accuracy drastically for wet snow (late winter - early spring). Furthermore, it is common practice to assume snow grain size and wetness to be constant to retrieve certain snow properties (e.g. snow depth). This approach is incorrect because these properties are space- and time- dependent, and largely impact the MW signal scattering. Moreover, the remaining operational snow depth products have not been validated against in-situ observations; which is detrimental to their performance and future calibrations.

This study is focused on the discovery of patterns in geospatial data sets using data mining techniques for mapping snow depth globally at 10 km spatial resolution. A methodology to develop a RS MW-based snow depth and water equivalent (SWE) product using regression tree algorithms is developed. The work divided into four main segments includes: (1) validation of RS-based IR and MW-retrieved Land Surface Temperature (LST) products, (2) studying snow wetness by developing, validating, and calibrating a Snow Wetness Profiler, (3) development of a regression tree algorithm capable of estimating snow depth based on radiative (MW observations) and physical snowpack properties, and (4) development of a global MW-RS-based snow depth product built on the regression tree algorithm.

A predictive model based on Regression Tree (RT) is developed in order to model snow depth and water equivalent at the Cooperative Remote Sensing Science and Technology Center – Snow Analysis and Field Experiment (CREST-SAFE). The RT performance analyzed based on contrasting training error, true prediction error, and variable importance estimates. The RT algorithm is then taken to a broader scale, and Japan Aerospace Exploration Agency (JAXA) Global Change Observation Mission – Water 1 (GCOM-W1) MW brightness temperature measurements were used to provide snow depth and SWE estimates. These SD and SWE estimates were evaluated against twelve (12) Snow Telemetry (SNOTEL) sites owned by the National Resources Conservation Service (NRCS) and JAXA’s own snow depth product. Results demonstrated that a RS MW-based RT algorithm is capable of providing snow depth and SWE estimates with acceptable accuracy for the continental United States, with some limitations. The major setback to the RT algorithm is that it will only provide estimates based on the data with which it was trained. Therefore, it is recommended that the work be expanded, and data from additional in-situ stations be used to re-train the RT algorithm. The CREST snow depth and water equivalent product, as it was named, is currently operational and publicly accessible at https://www.noaacrest.org//snow/products/.

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Khan, Salman Saeed. "Simulation of brightness temperatures for the microwave radiometer on the Aquarius/SAC-D mission." Orlando, Fla. : University of Central Florida, 2009. http://purl.fcla.edu/fcla/etd/CFE0002821.

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Guglielmetti, Massimo. "Remote sensing of temporally varying forest soil properties using microwave radiometry /." Zürich : ETH, 2007. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=17315.

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Sreerekha, T. R. [Verfasser]. "Impact of clouds on microwave remote sensing / von T. R. Sreerekha." Berlin : Logos-Verl, 2005. http://d-nb.info/979728304/34.

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Kolodner, Marc Alan. "Microwave remote sensing of sulfuric acid vapor in the Venus atmosphere." Diss., Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/30081.

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Isleifson, Dustin. "Simulation and measurement techniques for microwave remote sensing of sea ice." IEEE, 2010. http://hdl.handle.net/1993/4812.

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This dissertation presents new research into the study of simulation and measurement techniques for microwave remote sensing of sea ice. We have embarked on a major study of the microwave propagation and scattering properties of sea ice in an attempt to link the physics of the sea ice medium to experimentally obtained concomitant scatterometer measurements. During our fieldwork, we studied the polarimetric backscattering response of sea ice, focusing on newly-formed sea ice under a large assortment of surface coverage. Polarimetric backscattering results and physical data for 40 stations during the fall freeze-up of 2003, 2006, and 2007 are presented. Analysis of the co-polarization correlation coefficient showed its sensitivity to sea ice thickness and surface coverage and resulted in a statistically significant separation of ice thickness into two regimes: ice less than 6 cm thick and ice greater than 8 cm thick. A case study quantified the backscatter of snow-infiltrated frost fl owers on new sea ice, showing that the presence of the frost flowers enhanced the backscatter by more than 6 dB. In our simulation work, an efficient method for simulating scattering from objects in multi-layered media was incorporated into a scattered-field formulation of the FVTD method. A total-field 1D-FDTD solution to the plane-wave propagation through multi-layered meda was used as a source. The method was validated for a TE-polarized incident-field through comparisons with other numerical techniques involving examples of scattering from canonically-shaped objects. Methods for homogenization of inhomogeneous media were developed and validated using well-known dielectric mixture models. A Monte Carlo Method for simulating scattering from statistically rough surfaces was developed and was validated through favorable comparison with the SPM method for rough surface scattering. Finally, we presented a new Monte Carlo Method for simulating sea ice remote sensing that utilized the framework of the FVTD method for scattering simulations. The modeling process was driven by actual physical measurements of sea ice, wherein dielectric and physics-based modeling techniques were employed. The method was demonstrated through a series of case studies where the scattering from newly-formed sea ice was simulated using a TE-polarized incident- eld. Good agreement between experimental scatterometer measurements and simulated results was obtained for co-polarized returns, whereas cross-polarized results indicated that more depolarizing features must be taken into account.

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Podest, E. V. "Monitoring boreal landscape freeze/thaw transitions with spaceborne microwave remote sensing." Thesis, University of Dundee, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.516529.

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Scarito, Michael P. "Design and development of an airborne microwave radiometer for atmospheric sensing." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/66808.

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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2011.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 103-105).
Satellite-based passive microwave remote sensing is a valuable tool for global weather monitoring and prediction. This thesis presents the design and development of a low-cost airborne weather sensing instrument to independently validate a satellite-based sensor platform. The NPOESS Aircraft Sounder Testbed - K-band (NAST-K) is a passive microwave radiometer operating over approximately 200 MHz bandwidth centered at 23.8 GHz and 31.4 GHz, whose data can be used to find surface water, humidity, and temperature conditions. NAST-K flies along with the existing NAST-M instrument at an altitude of 18 km in the NASA ER-2 high altitude aircraft. The primary function of NASTK is to provide coverage of channels 1 and 2 of the Advanced Technology Microwave Sounder (ATMS) aboard the NPOESS Preparatory Project (NPP) satellite, scheduled to be launched in October 2011. The combined NAST-M/K system can validate the performance of ATMS on all channels with data products up to 17km, by underflying the satellite along the same ground track and collecting correlated data. NAST-K has fullwidth at half maximum beamwidths of 7.4° and 6.8° for the two channels respectively, which is approximately consistent with NAST-M. The effective spot size of NAST-K is 2.3km in diameter for the wider 23.8GHz channel at nadir, providing an areal resolution approximately 1000 times greater than ATMS. The major contributions of this thesis include the system-level design of NAST-K, the development of the video amplifier and embedded environmental monitor, and the analysis of the antenna system.
by Michael P. Scarito.
M.Eng.

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Tadross, Mark Alexander. "Microwave remote sensing of young sea ice in the Greenland Sea." Thesis, University of Cambridge, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.624765.

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Maughan, Sally M. "Distributed fibre sensing using microwave heterodyne detection of spontaneous Brillouin backscatter." Thesis, University of Southampton, 2002. https://eprints.soton.ac.uk/42382/.

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Brillouin scattering has been used for many years in optical fibre temperature and strain sensing applications, due to the dependence of both the power and the frequency shift of the scattered radiation on these two quantities. Simultaneous temperature and strain sensing is possible if both the power and frequency shift are measured. Much work has been published which presents either power or frequency shift measurements alone. Simultaneous measurement, however, has been less well documented, with all recent cases using direct detection of the backscattered power. As the input pulse power is increased, nonlinear processes ensue, compromising the accuracy of the sensor. These processes were investigated both experimentally and theoretically for a range of input pulse durations, focussing on their effect on Brillouin Power and frequency shift measurement.

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Lee, Michael W. "Microwave sensing of bulk electrical properties of tank track pad rubber." Thesis, Virginia Polytechnic Institute and State University, 1988. http://hdl.handle.net/10919/80089.

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A complex permittivity measurement system composed of a network analyzer and a open-ended coaxial waveguide has been used to evaluate the permittivity of rubber samples. The conductivity of rubber provides an indication of the dispersion of carbon black throughout the rubber matrix. The technique is based on the Deschamps antenna modeling theorem which relates the effective admittance of an antenna in some arbitrary medium to the effective admittance of the same antenna embedded in free space. This technique is well suited for material with loss tangents between 0.1 and 1.0. Only material within a radius on the order of the outer conductor radius of the coaxial waveguide is interrogated. Inferred permittivity measurements for rubber samples are presented. An APC-7 connector is used as the transducer which provides a means for convenient calibration because standard calibration terminations can be used. The amount of pressure from the sample applied to the waveguide affects reflection coefficient measurements, preventing consistent results.
Master of Science

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Muñoz, Martin Joan Francesc. "Development of novel instruments and techniques for passive microwave remote sensing." Doctoral thesis, Universitat Politècnica de Catalunya, 2021. http://hdl.handle.net/10803/672272.

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Earth Observation using satellites has helped to better model our planet. The goal of such systems is to provide large data sets to help to understand the effects of our actions on the climate, to predict storms in near real-time, to prevent forest fires, or to prevent desertification, among others. In the last years, thanks to the miniaturization of electronics a new type of satellite have become popular, the CubeSat, a small spacecraft weighing from 1 to 10 kg, which can carry different types of instruments. Thanks to the cost reduction of these new platforms, new techniques can be easily evaluated, and the concept of a mesh of sensors surrounding the Earth is becoming a reality. Besides, the suitability of new techniques is being proven for such small spacecraft, such as GNSS reflectometry (GNSS-R). GNSS-R instruments are typically cheaper, more efficient (in terms of power consumption), and smaller than their traditional equivalent ones. This Ph.D. thesis is devoted to the development of passive microwave remote sensing instruments for CubeSats. However, before entering into the instrument design, several field experiments were proposed to model and validate the use of GNSS-R under different conditions. This Ph.D. thesis is divided into three main parts. The first part is devoted to assessing the capabilities of GNSS-R to retrieve different geophysical parameters through a different set of field experiments. First, the achievable spatial resolution of L1 and L5 GNSS-R signals is analyzed under different conditions. Second, taking into account the incoherent integration limits previously analyzed, the coherency of GNSS-R signals is analyzed at L1 and L5 bands. Third, thanks to the use of short integration times, multiple reflections received in the GPS L5 reflected signal could be identified as multiple peaks, thanks to the narrower auto-correlation function of such signals. Over the ocean, these multiple peaks are analyzed and linked to the sea state. Over the Australian rainforest, these multiple peaks at L5 are linked to multiple reflections on top of the vegetation canopy and in the bare soil. Fourth, a methodology to estimate soil moisture content over land using GNSS-R signals is proposed. Finally, the use of GNSS-R signals to estimate sea-ice thickness and snow content over the sea-ice is examined thanks to the data collected by a circular polarization GNSS-R instrument part of the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition. The second part of this dissertation is devoted to the design, implementation, and test of three passive microwave instruments for CubeSats. First, the Flexible Microwave Payload -1 (FMPL-1) is proposed as part of the 3Cat-4 mission. The instrument includes three experiments in a single platform: a total power L-band radiometer with frequent internal calibration, an L1/L2 GNSS reflectometer, and an AIS receiver. Second, the FMPL-2 instrument is proposed as the main payload of the 3Cat-5/A, one of the two instruments composing the ESA FSSCat mission, the first third-party mission contributing to the Copernicus system based on CubeSats. This second instrument is the evolved version of FMPL-1 and can provide synchronous GNSS-R and L-band radiometry data. Finally, a third instrument, the FMPL-3, is proposed for the GNSSaS mission of the NSSTC from the UAE. This third instrument includes the first-ever GNSS-R receiver at L5 and aims to prove the capabilities of such signals from space. Finally, in the third part, the first results of FMPL-2 are presented and analyzed. The instrument was successfully launched into a Low Earth Orbit during the Vega VV16 flight. First, the results of FMPL-2 during the first two weeks of in-orbit validation are presented. Data-driven algorithms to estimate sea-ice concentration, thickness, and soil moisture content over land are implemented using L-band microwave radiometry data and GNSS-R data retrieved by FMPL-2.
iL'observació de la Terra mitjançant satèl·lits ha ajudat a modelar millor el nostre planeta. L'objectiu d'aquests sistemes és proporcionar grans conjunts de dades que ajudin a comprendre els efectes de les nostres accions sobre el clima, a predir tempestes gairebé en temps real, o a prevenir incendis forestals o a prevenir la desertificació, entre d’altres. En els darrers anys, gràcies a la miniaturització de l’electrònica, s’ha popularitzat un nou tipus de satèl·lit, el CubeSat, un petit satèl·lit que pesa menys de 10 kg i que pot transportar diferents tipus d’instruments. Gràcies a la reducció de costos d'aquestes noves plataformes, es poden avaluar fàcilment noves tècniques, com ara la reflectometria GNSS (GNSS-R). Els instruments GNSS-R solen ser més econòmics, més eficients (en termes de consum d’energia) i més petits que els equivalents tradicionals. Aquest doctorat la tesi es dedica al desenvolupament d'instruments de teledetecció passiva per microones per a CubeSats. No obstant això, abans d’entrar en el disseny de l’instrument, es van proposar diversos experiments de camp per modelar i validar l’ús de GNSS-R en diferents condicions. Aquesta tesi es divideix en tres parts principals. La primera part es dedica a avaluar les capacitats de GNSS-R per recuperar diferents paràmetres geofísics mitjançant un conjunt diferent d’experiments de camp. En primer lloc, s’analitza la resolució espacial assolible dels senyals GNSS-R L1 i L5 en diferents condicions. En segon lloc, tenint en compte els límits d’integració incoherents analitzats prèviament, s’analitza la coherència dels senyals GNSS-R a les bandes L1 i L5. En tercer lloc, gràcies a l’ús de curts temps d’integració, les múltiples reflexions rebudes al senyal reflectit GPS L5 s'identifiquen com a múltiples pics. Sobre l’oceà, aquests múltiples pics s’analitzen i es relacionen amb l’estat del mar. A la selva tropical australiana, aquests múltiples pics a L5 es relacionen amb múltiples reflexions a la part superior de la vegetació i al sòl nu. En quart lloc, es proposa una metodologia per estimar el contingut d’humitat del sòl sobre la terra mitjançant senyals GNSS-R. Finalment, l’ús de senyals GNSS-R per estimar el gruix del gel marí i el contingut de neu sobre el gel marí s’examina gràcies a les dades recollides per un instrument GNSS-R de polarització circular que forma part d'expedició "MOSAiC". La segona part d'aquesta dissertació es dedica al disseny, implementació i prova de tres instruments de microones passius per a CubeSats. En primer lloc, es proposa la FMPL-1 com a part de la missió 3Cat-4. L'instrument inclou tres experiments en una única plataforma: un radiòmetre de banda L de potència total amb un calibratge intern freqüent, un reflectòmetre GNSS L1/L2 i un receptor AIS. En segon lloc, es proposa l’instrument FMPL-2 com a principal càrrega útil del 3Cat-5/A, un dels dos instruments que componen la missió FSSCat de la ESA, la primera missió subcontractada basada en CubeSats que contribueix al sistema Copernicus. Aquest segon instrument és la versió evolucionada de FMPL-1 i pot proporcionar dades de radiometria GNSS-R i de banda L síncronament. Finalment, es proposa un tercer instrument, el FMPL-3, per a la missió GNSSaS del NSSTC dels Emirats Àrabs Units. Aquest tercer instrument inclou el primer receptor GNSS-R de L5 i pretén demostrar les capacitats d’aquests senyals des de l’espai. Finalment, a la tercera part es presenten i analitzen els primers resultats de FMPL-2. L'instrument es va llançar amb èxit a una òrbita terrestre baixa durant el vol Vega VV16. En primer lloc, es presenten els resultats de FMPL-2 durant les dues primeres setmanes de validació en òrbita. Algoritmes basats en dades per estimar la concentració i el gruix del gel oceànic, i el contingut d’humitat sobre la terra s'implementen mitjançant dades de radiòmetre

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39

Ashcraft, Ivan S. "Microwave Remote Sensing of the Greenland Ice Sheet: Models and Applications." Diss., CLICK HERE for online access, 2004. http://contentdm.lib.byu.edu/ETD/image/etd532.pdf.

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40

Al-Jassar, Hala Khalid. "Retrieval of surface microwave emissivity using multisensor satellite measurements." Thesis, University College London (University of London), 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.283304.

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41

Ruston, Benjamin C. "Characteristics of summertime microwave land emissivity over the conterminous United States." Access citation, abstract and download form; downloadable file 5.20 Mb, 2004. http://wwwlib.umi.com/dissertations/fullcit/3131699.

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42

Kim, Rhae Sung. "Estimating snow depth of alpine snowpack via airborne multifrequency passive microwave radiance observations." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1503071052341111.

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43

Karpowicz, Bryan Mills. "In search of water vapor on Jupiter: laboratory measurements of the microwave properties of water vapor and simulations of Jupiter's microwave emission in support of the Juno mission." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/33947.

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This research has involved the conduct of a series of laboratory measurements of the centimeter-wavelength opacity of water vapor along with the development of a hybrid radiative transfer ray-tracing simulator for the atmosphere of Jupiter which employs a model for water vapor opacity derived from the measurements. For this study an existing Georgia Tech high-sensitivity microwave measurement system (Hanley and Steﬀes , 2007) has been adapted for pressures ranging from 12-100 bars, and a corresponding temperature range of 293-525°K. Water vapor is measured in a mixture of hydrogen and helium. Using these measurements which covered a wavelength range of 6--20 cm, a new model is developed for water vapor absorption under Jovian conditions. In conjunction with our laboratory measurements, and the development of a new model for water vapor absorption, we conduct sensitivity studies of water vapor microwave emission in the Jovian atmosphere using a hybrid radiative transfer ray-tracing simulator. The approach has been used previously for Saturn (Hoﬀman, 2001), and Venus (Jenkins et al., 2001). This model has been adapted to include the antenna patterns typical of the NASA Juno Mission microwave radiometer (NASA/Juno -MWR) along with Jupiter's geometric parameters (oblateness), and atmospheric conditions. Using this adapted model we perform rigorous sensitivity tests for water vapor in the Jovian atmosphere. This work will directly improve our understanding of microwave absorption by atmospheric water vapor at Jupiter, and improve retrievals from the Juno microwave radiometer. Indirectly, this work will help to refine models for the formation of Jupiter and the entire solar system through an improved understanding of the planet-wide abundance of water vapor which will result from the successful opreation of the Juno Microwave Radiometer (Juno-MWR).

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Devaraj, Kiruthika. "The centimeter- and millimeter-wavelength ammonia absorption spectra under jovian conditions." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/42806.

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Accurate knowledge of the centimeter- and millimeter-wavelength absorptivity of ammonia is necessary for the interpretation of the emission spectra of the jovian planets. The objective of this research has been to advance the understanding of the centimeter- and millimeter-wavelength opacity spectra of ammonia under jovian conditions using a combination of laboratory measurements and theoretical formulations. As part of this research, over 1000 laboratory measurements of the 2-4 mm-wavelength properties of ammonia under simulated upper and middle tropospheric conditions of the jovian planets, and approximately 1200 laboratory measurements of the 5-20 cm-wavelength properties of ammonia under simulated deep tropospheric conditions of the jovian planets have been performed. Using these and pre-existing measurements, a consistent mathematical formalism has been developed to reconcile the centimeter- and millimeter-wavelength opacity spectra of ammonia. This formalism can be used to estimate the opacity of ammonia in a hydrogen/helium atmosphere in the centimeter-wavelength range at pressures up to 100 bar and temperatures in the 200 to 500 K range and in the millimeter-wavelength range at pressures up to 3 bar and temperatures in the 200 to 300 K range. In addition, a preliminary investigation of the influence of water vapor on the centimeter-wavelength ammonia absorptivity spectra has been conducted. This work addresses the areas of high-sensitivity centimeter- and millimeter-wavelength laboratory measurements, and planetary science, and contributes to the body of knowledge that provides clues into the origin of our solar system. The laboratory measurements and the model developed as part of this doctoral research work can be used for interpreting the emission spectra of jovian atmospheres obtained from ground-based and spacecraft-based observations. The results of the high-pressure ammonia opacity measurements will also be used to support the interpretation of the microwave radiometer (MWR) measurements on board the NASA Juno spacecraft at Jupiter.

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Hoffman, James Patrick. "Microwave opacity of phosphine : application to remote sensing of the atmospheres of the outer planets." Diss., Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/14969.

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Hanna, Rafik. "VALIDATION OF QUICKSCAT RADIOMETER (QRAD) MICROWAVE BRIGHTNESS TEMPERTURE MEASURMENTS." Doctoral diss., University of Central Florida, 2009. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3990.

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After the launch of NASA's SeaWinds scatterometer in 1999, a radiometer function was implemented in the Science Ground Data Processing Systems to allow the measurement of the earth's microwave brightness temperature. This dissertation presents results of a comprehensive validation to assess the quality of QRad brightness temperature measurements using near-simultaneous ocean Tb comparisons between the SeaWinds on QuikSCAT (QRad) and WindSat polarimetric radiometer on Coriolis. WindSat was selected because it is a well calibrated radiometer that has many suitable collocations with QuikSCAT; and it has a 10.7 GHz channel, which is close to QRad frequency of 13.4 GHz. Brightness temperature normalizations were made for WindSat before comparison to account for expected differences in Tb with QRad because of incidence angle and channel frequency differences. Brightness temperatures for nine months during 2005 and 2006 were spatially collocated for rain-free homogeneous ocean scenes (match-ups) within 1° latitude x longitude boxes and within a ± 60 minute window. To ensure high quality comparison, these collocations were quality controlled and edited to remove non-homogenous ocean scenes and/or transient environmental conditions, including rain contamination. WindSat and QRad Tb's were averaged within 1° boxes and these were used for the radiometric inter-calibration analysis on a monthly basis. Results show that QRad calibrations are stable in the mean within ± 2K over the yearly seasonal cycle.
Ph.D.
School of Electrical Engineering and Computer Science
Engineering and Computer Science
Electrical Engineering PhD

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47

Turner, Barry John. "Spatial sampling and vertical variability effects on microwave radiometer rainfall estimates." Thesis, McGill University, 1991. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=59910.

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Three-dimensional radar data for three Florida storms are used with a radiative transfer model to simulate observations at 19 GHz by a nadir pointing, satellite bourne microwave radiometer. Estimates were made of spatial sampling errors due to both horizontal and vertical variability of the precipitation. Calibrated radar data were taken as realistic representations of rainfall fields.
The optimal conversion between microwave brightness temperature and rainfall rate was highly sensitive to the spatial resolution of observations. Retrievals were made from the simulated microwave measurements using rainfall retrieval functions optimized for each resolution and for each storm case.
There is potential for microwave radiometer measurements from the planned TRMM satellite to provide better 'snapshot' estimates than area-threshold VIS/IR methods. Variability of the vertical profile of precipitation did not seriously reduce accuracy. However, it is crucial that calibration of retrieval methods be done with ground truth of the same spatial resolution.

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Jin, Kyoung-Wook. "Global oceanic rainfall estimation from AMSR-E data based on a radiative transfer model." Diss., Texas A&M University, 2005. http://hdl.handle.net/1969.1/3266.

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An improved physically-based rainfall algorithm was developed using AMSR-E data based on a radiative transfer model. In addition, error models were designed and embedded in the algorithm to assess retrieval errors quantitatively and to reduce net retrieval uncertainties. The algorithm uses six channels (dual polarizations at 36.5, 18.7 and 10.65GHz) and retrieves rain rates on a pixel-by-pixel basis. Monthly rain totals are estimated by summing average rain rates computed by merging six rain rates based on proper weights that are estimated from error models. Error models were constructed based upon the principal error sources of rainfall retrieval such as beam filling error, drop size distribution uncertainty and instrument calibration errors. Several improved schemes that minimize uncertainties of the rainfall retrieval were developed in this study. In particular, improved offset correction that corrects the biases near zero rain plays a very important role for reducing uncertainties which are mainly driven by calibration uncertainty including the modeling errors. AMSR-E's larger calibration uncertainty was substantially absorbed by this offset correction as well as by the weighted average scheme to combine all six channels optimally. As a framework for inter-comparison with the experimental algorithm, the current operational algorithm (NASA, level 3 algorithm) was also updated with respect to AMSR-E data. The experimental algorithm was compared with the operational algorithm for both AMSR-E and TMI data and rainfall retrieval uncertainties were analyzed using error models. When the experimental algorithm was used, many limitations of the operational algorithm were overcome and uncertainties of rainfall retrieval were considerably eliminated.

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Laupattarakasem, Peth. "An improved hurricane wind vector retrieval algorithm using SeaWinds scatterometer." Orlando, Fla. : University of Central Florida, 2009. http://purl.fcla.edu/fcla/etd/CFE0002654.

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Barrowes, Benjamin E. "YSCAT backscatter distributions /." Diss., CLICK HERE for online access, 1999. http://contentdm.lib.byu.edu/ETD/image/etd2.pdf.

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Dissertations / Theses on the topic 'Microwave sensing'

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