Download or read book Application and Evaluation of Wind Retrieval Algorithms for a Single Doppler Radar written by Kurt Duane Hondl and published by . This book was released on 1990 with total page 346 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Variational Analysis Methods for Retrieval of Wind Field from Single doppler Radar Data written by Stéphane Laroche and published by . This book was released on 1994 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The variational analysis methods are applied to retrieve the steady state wind field from single-Doppler radar data. The wind field is retrieved by fitting, in the least-squares sense, constraining model equations to observations measured during a short assimilation period (2 or 3 time sequences). The weak and strong constraint formalisms are reviewed and examined using the one-dimensional linear advection equation as a constraint. It is shown that the retrieval is not unique, but the problem can be controlled by a smoothness constraint. Variational two-dimensional and three-dimensional wind retrieval algorithms are developed and tested using actual dual-Doppler radar data. The conservation of reflectivity and the radial momentum equation are used as weak constraints in both algorithms. The anelastic form of the continuity equation is also included as a strong constraint in the three-dimensional algorithm. The two-dimensional algorithm is tested and compared to echo tracking methods using Doppler radar observations in the clear-air planetary boundary layer. The resolution at which the methods can effectively retrieve the horizontal wind field is examined in detail. The variational algorithm can properly retrieve wind structures greater than 10 km wavelength. The three-dimensional algorithm is tested using observations of a precipitating microburst. It is demonstrated that the three-dimensional wind field can be retrieved, but the method fails near the ground level. In addition, the retrieval is sensitive to the radar position relative to the observational domain due to systematic model errors. The computational efficiency of the three-dimensional wind retrieval algorithm allows its semi-operational implementation at the J. S. Marshall Radar Observatory of McGill University." --

Download or read book Doppler Radar Weather Observations written by Richard J. Doviak and published by Academic Press. This book was released on 2014-08-27 with total page 591 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book reviews the principles of Doppler radar and emphasizes the quantitative measurement of meteorological parameters. It illustrates the relation of Doppler radar data and images to atmospherix phenomena such as tornados, microbursts, waves, turbulence, density currents, hurricanes, and lightning. Radar images and photographs of these weather phenomena are included. Polarimetric measurements and data processing An updated section on RASS Wind profilers Observations with the WSR-88D An updated treatment of lightning Turbulence in the planetary boundary layer A short history of radar Chapter problem sets

Download or read book Correlation of Doppler radar Velocities and Reflectivities with Application to Retrieving the Transverse Wind written by Glenn Richard Smythe and published by . This book was released on 1981 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Development and Evaluation of New Algorithms for the Retrieval of Wind and Internal Wave Parameters from Shipborne Marine Radar Data written by Björn Lund and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The goal of this work is to develop and evaluate techniques for the retrieval of wind and internal wave (IW) information from marine X-band radar data. While ocean wind measurements are crucial for the transfer of energy and momentum across the air-sea interface, IWs play an important role in tidal energy transport. Marine radars work by transmitting microwave energy from a rotating antenna that also measures the backscatter. The radar backscatter from the sea surface is controlled by the wind-generated small ripple waves through the Bragg-scattering mechanism. Surface winds are thus the dominant factor for generating the radar backscatter. The varying surface current fields associated with IWs interact with the ripples, generating rough convergent and smooth divergent zones. Radars are capable of imaging such IW-induced surface signatures as bands of enhanced and weakened backscatter. The advantage of radar-based wind information is that it is obtained from a large area around the instrument. Marine radar wind data are therefore much less likely to be affected by platform-induced air flow distortions than in-situ measurements. Previous investigators have already demonstrated marine radar's suitability as a wind sensor [31, 30], however, these works have been limited to fixed-platform data. Here, the focus lies on shipborne marine radar data. Such data present the challenge that the existing wind streak-based approach for retrieving wind directions cannot be directly applied. This is because the wind streak signal may become obscured by the horizontal ship motion, since wind streaks become visible only after averaging over a sequence of radar images. In addition, moving platforms face a greater variability of conditions, which may further complicate a radar-based wind retrieval. Grazing incidence HH-polarized (horizontal transmit and receive) X-band radar data exhibit a single intensity peak in upwind direction. To retrieve the wind direction, this work proposes a least-squares fit technique that identifies the upwind peak in the range-averaged backscatter dependency on the antenna look direction. This technique requires no motion correction and is therefore well-suited for shipborne data. In addition, it functions well even if sections of the radar field of view are masked. An empirical model function is derived to retrieve the wind speed from the mean radar backscatter intensity. Data from the U.S. Office of Naval Research (ONR) Impact of Typhoons on the Ocean in the Pacific (ITOP) experiment are used for a comparison between radar-based wind estimates and anemometer measurements. The two data sets show good agreement. In addition, this work proposes a technique that uses geolocated marine radar data to extract wind streak information through a localized Radon transform. To compare streak- and upwind peak-based wind direction retrieval techniques, fixed and moving platform marine radar data from the ONR-sponsored High Resolution Air-Sea Interaction (Hi-Res) experiment are used. Wind directions obtained using the upwind peak method show a better agreement with the reference data than those obtained from the wind streaks. The difference between fixed and moving platform for the wind streak approach indicates that the image geolocation affects the wind retrieval negatively. Standard deviations as low as 6.0° and 0.42 m/s for the comparison between radar-based and reference wind data show that marine radars can yield highly reliable wind estimates. Regarding IWs, a new fully automated tool to retrieve IW signatures from marine radar image sequences is developed and applied to data collected during ONR's Non-Linear Internal Wave Initiative / Shallow Water '06 experiment (NLIWI/SW06). Marine radars have the advantage over satellite systems that their high temporal resolution enables the study of the IW evolution. The proposed technique employs our knowledge about the wind dependency of the radar backscatter to correct for the image ramp, i.e. the return signal's dependency on range and antenna look direction. The ramp-corrected radar images are then geolocated and averaged, which greatly enhances the IW signal. By determining the IW group velocity and correcting for it before the radar images are averaged, the IW signal is further enhanced. Such pre-processing enables a reliable retrieval of IW surface signatures by clustering local peaks and troughs, and tracking those clusters through time. This work also includes a detailed analysis of data collected during the tracking of a particularly energetic IW. The radar-derived time series of IW speed, direction, and soliton maps yield unique information about the IW's spatio-temporal evolution, including evidence of wave-wave interactions. In addition, it is demonstrated that marine radar data can be used to retrieve information about the interior ocean dynamics associated with the IW. The IW-induced backscatter modulation is correlated with the measured surface current gradients and IW amplitudes. Alternatively, results are shown where IW amplitudes were derived from the distances between positive and negative radar backscatter peaks. This approach was first introduced by Xue et al. [132] and is based on an extended Korteweg-de-Vries (eKdV) equation. This approach has the advantage that it is much less dependent on the prevailing wind conditions. To summarize, the marine radar backscatter dependency on wind is analyzed, and new wind retrieval techniques from shipborne radar data are proposed. The gained knowledge on the backscatter's wind dependency is then applied to marine radar data containing IW surface signatures. This work proposes a new methodology for retrieving these signatures and uses the resulting IW soliton maps to derive information about the IW-associated interior ocean dynamics.

Download or read book Implementation and Evaluation of the New Wind Algorithm in Nasa s 50 MHz Doppler Radar Wind Profiler written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-18 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt: The purpose of this report is to document the Applied Meteorology Unit's implementation and evaluation of the wind algorithm developed by Marshall Space Flight Center (MSFC) on the data analysis processor (DAP) of NASA's 50 MHz doppler radar wind profiler (DRWP). The report also includes a summary of the 50 MHz DRWP characteristics and performance and a proposed concept of operations for the DRWP. Taylor, Gregory E. and Manobianco, John T. and Schumann, Robin S. and Wheeler, Mark M. and Yersavich, Ann M. Unspecified Center ALGORITHMS; DOPPLER RADAR; METEOROLOGICAL RADAR; METEOROLOGY; WIND PROFILES; WIND VELOCITY MEASUREMENT; DATA REDUCTION; ROOT-MEAN-SQUARE ERRORS; WIND (METEOROLOGY); WIND VELOCITY...

Download or read book Foundations for Innovative Application of Airborne Radars written by Alexey Nekrasov and published by Springer Science & Business Media. This book was released on 2013-10-09 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt: The ‘wind vector’ – wind speed and direction – is a main meteorological quantity and relevant for air-sea exchange processes. This book explores the use of several airborne microwave instruments, some of which are part of standard aircraft equipment, in determining the local wind vector over water. This is worthwhile as local wind information is usually only available at measurements sites like weather stations and airports, and global wind information from satellites has very coarse resolution and poor temporal coverage – at most a few times daily. In his book, Nekrasov uses known results in a novel way and gives explicit and application-oriented descriptions how to additionally retrieve local wind information from standard airborne microwave instruments. The results presented here are highly valuable for flight operation above the sea (e.g., search-and-rescue) but also for complementing other measurements of atmospheric or oceanic parameters during research flights.

Download or read book Doppler Radar Observations written by Joan Bech and published by BoD – Books on Demand. This book was released on 2012-04-05 with total page 486 pages. Available in PDF, EPUB and Kindle. Book excerpt: Doppler radar systems have been instrumental to improve our understanding and monitoring capabilities of phenomena taking place in the low, middle, and upper atmosphere. Weather radars, wind profilers, and incoherent and coherent scatter radars implementing Doppler techniques are now used routinely both in research and operational applications by scientists and practitioners. This book brings together a collection of eighteen essays by international leading authors devoted to different applications of ground based Doppler radars. Topics covered include, among others, severe weather surveillance, precipitation estimation and nowcasting, wind and turbulence retrievals, ionospheric radar and volcanological applications of Doppler radar. The book is ideally suited for graduate students looking for an introduction to the field or professionals intending to refresh or update their knowledge on Doppler radar applications.

Download or read book Radar for Meteorological and Atmospheric Observations written by Shoichiro Fukao and published by Springer Science & Business Media. This book was released on 2013-08-16 with total page 561 pages. Available in PDF, EPUB and Kindle. Book excerpt: Epoch-making progress in meteorology and atmospheric science has always been hastened by the development of advanced observational technologies, in particular, radar technology. This technology depends on a wide range of sciences involving diverse disciplines, from electrical engineering and electronics to computer sciences and atmospheric physics. Meteorological radar and atmospheric radar each has a different history and has been developed independently. Particular radar activities have been conducted within their own communities. Although the technology of these radars draws upon many common fields, until now the interrelatedness and interdisciplinary nature of the research fields have not been consistently discussed in one volume containing fundamental theories, observational methods, and results. This book is by two authors who, with long careers in the two fields, one in academia and the other in industry, are ideal partners for writing on the comprehensive science and technology of radars for meteorological and atmospheric observations.

Download or read book Masters Theses in the Pure and Applied Sciences written by W. H. Shafer and published by Plenum Publishing Corporation. This book was released on 1992 with total page 392 pages. Available in PDF, EPUB and Kindle. Book excerpt: Masters Theses Listed by Discipline: Aerospace Engineering. Agricultural Economics, Sciences and Engineering. Architechtural Engineering and Urban Planning. Astronomy. Astrophysics. Ceramic Engineering. Communications Engineering and Computer Science. Cryogenic Engineering. Electrical Engineering. Engineering Mechanics. Engineering Physics. Engineering Science. Fuels, Combustion, and Air Pollution. General and Environmental Engineering. Geochemistry and Soil Science. Geological Sciences and Geophysical Engineering. Geology and Earth Science. Geophysics. Industrial Engineering. Marine and Ocean Engineering. Materials Science and Engineering. Mechanical Engineering and Bioengineering. Metallurgy. Meteorology and Atmospheric Science. 17 additional disciplines. Index.

Download or read book Monthly Weather Review written by and published by . This book was released on 1994 with total page 1212 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Foundations for Innovative Application of Airborne Radars written by Alexey Nekrasov and published by Springer Nature. This book was released on 2021-04-02 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book discusses methods for measuring the water surface backscattering signature and estimating the near-surface wind vector over water using airborne radars, in addition to their standard application. Airborne FMCW demonstrator system, Doppler navigation system, airborne weather radar, airborne radar altimeter, and airborne precipitation radar are analyzed in order to be used for that purpose. The radars functionality is enhanced for their operation in a scatterometer mode. A circle flight and/or a rectilinear flight of an aircraft over the water surface is considered depending on the radar design features to perform measurements of the azimuth normalized radar cross section curve of the water surface and/or the near-surface wind speed and direction. Flight recommendations to perform measurements along with algorithms for measuring the water surface backscattering signature and for retrieval of the wind speed and direction over water are presented.

Download or read book Variational Analysis Methods for Retrieval of Wind Field from Single Doppler Radar Data microform written by Stéphane Laroche and published by National Library of Canada = Bibliothèque nationale du Canada. This book was released on 1994 with total page 384 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Global Evaluation of Special Sensor Microwave imager Ocean Surface Wind Speed Retrieval Algorithms for the Period September 1991 April 1992 written by William A. Hesser and published by . This book was released on 1995 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Fleet Numerical Meteorology and Oceanography Center (FNMOC) has the charter to provide Special Sensor Microwave/Imager (SSMI) data to the DOD and the NOAA. This has led FNMOC to examine new methods for processing SSM/I data to generate SSM/I products. Of particular interest is the ability to use the SSM/I to remotely sense ocean surface winds. For this study four candidate wind retrieval algorithms initially proposed at the SSM/I Algorithm Symposium held in June, 1993 are examined for potential implementation at FNMOC. Previous calibrarion/validarion studies of the efficacy of wiod speed algorithms focused on regional (mid-latitude or tropical) data sets prompting the requirement to develop a more encompassing, global data set on which to evaluate the proposed algorithms. Comparisons of SSM/I wind retrieval methods reveal that the current FNMOC operational algorithm overestimates wind speeds when atruospheric water vapor content exceeds 5O kg/sq-m2. Adjustments made to this algorithm effectively mitigate the high wind speed bias, but at the cost of eliminating a significant amount of data. Neural network algorithms display high wind speed bias for winds above 11 m/s and low wind speed bias for winds below 4 m/s. The performance of neural network algorithms is largely independent of atmospheric moisture content. A new, global training data set is necessary to enable neural network algorithms to perform properly over the full range of global wind speeds. The use of brightness temperature based rain flags are recommended for use in all wind speed retrieval methods.

Download or read book Global Evaluation of Special Sensor Microwave imager Ocean Surface Wind Speed Retrieval Algorithms for the Period September 1991 April 1992 written by William A. Hesser and published by . This book was released on 1995 with total page 101 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Fleet Numerical Meteorology and Oceanography Center (FNMOC) has the charter to provide Special Sensor Microwave/Imager (SSMI) data to the DOD and the NOAA. This has led FNMOC to examine new methods for processing SSM/I data to generate SSM/I products. Of particular interest is the ability to use the SSM/I to remotely sense ocean surface winds. For this study four candidate wind retrieval algorithms initially proposed at the SSM/I Algorithm Symposium held in June, 1993 are examined for potential implementation at FNMOC. Previous calibrarion/validarion studies of the efficacy of wiod speed algorithms focused on regional (mid-latitude or tropical) data sets prompting the requirement to develop a more encompassing, global data set on which to evaluate the proposed algorithms. Comparisons of SSM/I wind retrieval methods reveal that the current FNMOC operational algorithm overestimates wind speeds when atruospheric water vapor content exceeds 5O kg/sq-m2. Adjustments made to this algorithm effectively mitigate the high wind speed bias, but at the cost of eliminating a significant amount of data. Neural network algorithms display high wind speed bias for winds above 11 m/s and low wind speed bias for winds below 4 m/s. The performance of neural network algorithms is largely independent of atmospheric moisture content. A new, global training data set is necessary to enable neural network algorithms to perform properly over the full range of global wind speeds. The use of brightness temperature based rain flags are recommended for use in all wind speed retrieval methods.

Download or read book A Study of Wind Field Retrieval from Single Doppler Radar Data written by and published by . This book was released on 1997 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Preprints Radar Meteorology Conference written by and published by . This book was released on 1995 with total page 884 pages. Available in PDF, EPUB and Kindle. Book excerpt: