Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 31 for “"radar backscatter"”.
-
Azimuth Modulation of the Radar Backscatter at Near-Normal Incidence
<p>Radar observations of the ocean surface are becoming increasingly important. Common applications are wind retrieval and global weather forecasting and characterization. Because of the common use of ocean radar measurements, it is important to understand the sensitivity of the backscatter to both …
-
Integrated two-way radar backscatter communication and sensing with low-power IoT tags
Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2026-08-01
-
A Wind and Rain Backscatter Model Derived from AMSR and SeaWinds Data
… surface roughening and the normalized radar backscatter cross-section. Recently, an algorithm for simultaneously retrieving wind and rain (SWR) from scatterometer measurements was developed that enables SeaWinds to correct rain-corrupted wind measurements and retrieve rain rate data. …
-
A New Method for Melt Detection on Antarctic Ice-Shelves and Scatterometer Calibration Verification
<p>Ku-band dual-polarization radar backscatter measurements from the SeaWinds on QuikScat scatterometer and microwave radiometer measurements from the Special Sensor Microwave/Imager (SSM/I) are used to determine periods of surface melt and freeze in the Antarctic ice-shelves. The normalized radar …
-
Solar flare effects observed over Jicamarca during MST-ISR experiments
… The observations were made while the Jicamarca radar was conducting combined observations in mesosphere-stratosphere-troposphere (MST) and incoherent scatter radar (ISR) modes. Combined MST-ISR campaigns have been conducted at JRO from December 2004 until January 2009 with the purpose of …
-
Stratospheric scattering of radio waves and the Jicamarca radio telescope
Radar backscatter from the 15 to 35 km height range provides information about the dynamics and turbulent mixing of the stratosphere. The 3-dimensional space spectrum of turbulent fluctuations, the mean wind velocity, and the root-mean-square velocity fluctuations are directly related to the …
-
Calibration of and Attitude Error Estimation for a Spaceborne Scatterometer using Measurements Over Land
… (ADEOS). NSCAT's primary mission was to measure radar backscatter over the world's oceans. These measurements are used to generate estimates of ocean wind speed and direction. Scatterometers must be calibrated before their measurements are scientifically useful. However, the calibration of NSCAT …
-
Hurricane Wind Retrieval Algorithm Development For An Airborne Conical Scanning Scatterometer
… scatterometer measurements of ocean surface backscatter. The algorithm is developed to best suit the specifications for the National Oceanic and Atmospheric Administration (NOAA) Hurricane Research Division's airborne scatterometer – Integrated Wind and Rain Airborne Profiler (IWRAP). Based …
-
An Analysis of SeaWinds Simultaneous Wind/Rain Retrieval in Severe Weather Events
… near-surface wind vectors by relating measured radar backscatter to a geophysical model function. However, SeaWinds measurements are also sensitive to rain, and conventional wind retrieval degrades in rainy conditions. An algorithm that exploits SeaWinds' sensitivity to both wind and rain has be …
-
Radio and Optical Techniques for Locating Equatorial Plasma Irregularities
… with ionosondes and incoherent scatter radar, and scintillation (fading) of trans-ionospheric radio communication and navigation signals are well-known symptoms of depletions. This dissertation describes new techniques to combine optical and radio ionospheric remote sensing data in …
-
The Polarimetric Impulse Response and Convolutional Model for the Remote Sensing of Layered Vegetation
… efficient, physics-based model to compute the radar backscatter from forest canopies. Several models attempt to predict the backscatter coefficient for random forest canopies by using the Vector Radiative Transfer (VRT) Theory with success, however, these models often rely on purely …
-
Statistical correlation as a tool in propagation studies
… as a means to enhance the use of ground-based radar in analyzing satellite-path millimeter wave propagation through rain and ice crystals. The technique presented involves correlating dB values of the satellite signal attenuation and polarization isolation with dBZ values of radar backscatter …
-
Melt Detection and Estimation in Greenland Using Tandem QuikSCAT and SeaWinds Scatterometers
Ku-band dual-polarization radar backscatter measurements from the SeaWinds on QuikScat (QuikScat) and SeaWinds on ADEOS-2 (SeaWinds) scatterometers are used to classify the melt state and estimate melt severity in Greenland. Backscatter measurements are organized into high temporal and high spatial …
-
Microwave Remote Sensing of Saharan Ergs and Amazon Vegetation
… of the Sahara desert and the Amazon vegetation. Radar and radiometric responses of the Saharan ergs are related to geophysical properties of sand formations and near surface winds. The spatial and temporal variability of the Amazon vegetation is studied using multi-frequency and …
-
An Implementation of Field-Wise Wind Retrieval for Seawinds on QuikSCAT
… technique to derive wind estimates from radar backscatter measurements. In contrast to the more traditional method known as point-wise wind retrieval, field-wise techniques estimate wind field model parameters. In this way, neighboring wind vectors are jointly estimated, ensuring …
-
Dual-polarization meteorological radar: theory and design
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, …
-
A Roughness Correction for Aquarius Ocean Brightness Temperature Using the CONAE MicroWave Radiometer
… baseline approach uses the radar scatterometer to provide this ocean roughness correction, through the correlation of radar backscatter with the excess ocean emissivity. In contrast, this dissertation develops an ocean roughness correction for AQ measurements using the …
-
On the role of high frequency waves in ocean altimetry
… wind stress, and sea level using a microwave radar altimeter. The data were collected from a low-flying aircraft using a sensor suite designed to measure the surface waves, radar backscatter, the atmospheric flow, and turbulent fluxes within the marine boundary layer. This uncommon ensemble …
-
Radio and optical studies of natural and artificially stimulated geospace plasmas
… of pump-induced enhancement in the UHF ion-line backscatter power. This effect has been modeled using electron temperature and density perturbation equations. It is concluded that a maximum electron temperature enhancement of up to ∼5700 K was achieved on average. Possible mechanisms and …
-
Observational studies of scatterometer ocean vector winds in the presence of dynamic air-sea interactions
… does not in fact measure wind directly; received radar backscatter is proportional to the roughness of the ocean's surface, which is primarily modified by wind speed and direction. As scatterometry has evolved in recent decades, highly calibrated geophysical model functions have been designed to …
Page 1 of 2