+publisher:"Colorado State University" +contributor:("Notaros, Branislav M.")

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1. Chen, Haonan. Quantitative precipitation estimation for an X-band weather radar network.

Degree: MS(M.S.), Electrical and Computer Engineering, 2013, Colorado State University

URL: http://hdl.handle.net/10217/79026

► Currently, the Next Generation (NEXRAD) radar network, a joint effort of the U.S. Department of Commerce (DOC), Defense (DOD), and Transportation (DOT), provides radar data… (more)

▼ Currently, the Next Generation (NEXRAD) radar network, a joint effort of the U.S. Department of Commerce (DOC), Defense (DOD), and Transportation (DOT), provides radar data with updates every five-six minutes across the United States. This network consists of about 160 S-band (2.7 to 3.0 GHz) radar sites. At the maximum NEXRAD range of 230 km, the 0.5 degree radar beam is about 5.4 km above ground level (AGL) because of the effect of earth curvature. Consequently, much of the lower atmosphere (1-3 km AGL) cannot be observed by the NEXRAD. To overcome the fundamental coverage limitations of today's weather surveillance radars, and improve the spatial and temporal resolution issues, the National Science Foundation Engineering Center (NSF-ERC) for Collaborative Adaptive Sensing of the Atmosphere (CASA) was founded to revolutionize weather sensing in the lower atmosphere by deploying a dense network of shorter-range, low-power X-band dual-polarization radars. The distributed CASA radars are operating collaboratively to adapt the changing atmospheric conditions. Accomplishments and breakthroughs after five years operation have demonstrated the success of CASA program. Accurate radar quantitative precipitation estimation (QPE) has been pursued since the beginning of weather radar. For certain disaster prevention applications such as flash flood and landslide forecasting, the rain rate must however be measured at a high spatial and temporal resolution. To this end, high-resolution radar QPE is one of the major research activities conducted by the CASA community. A radar specific differential propagation phase (Kdp)-based QPE methodology has been developed in CASA. Unlike the rainfall estimation based on the power terms such as radar reflectivity (Z) and differential reflectivity (Zdr), Kdp-based QPE is less sensitive to the path attenuation, drop size distribution (DSD), and radar calibration errors. The CASA Kdp-based QPE system is also immune to the partial beam blockage and hail contamination. The performance of the CASA QPE system is validated and evaluated by using rain gauges. In CASA's Integrated Project 1 (IP1) test bed in Southwestern Oklahoma, a network of 20 rainfall gauges is used for cross-comparison. 40 rainfall cases, including severe, multicellular thunderstorms, squall lines and widespread stratiform rain, that happened during years 2007 - 2011, are used for validation and evaluation purpose. The performance scores illustrate that the CASA QPE system is a great improvement compared to the current state-of-the-art. In addition, the high-resolution CASA QPE products such as instantaneous rainfall rate map and hourly rainfall amount measurements can serve as a reliable input for various distributed hydrological models. The CASA QPE system can save lived and properties from hazardous flash floods by incorporating hydraulic and hydrologic models for flood monitoring and warning. Advisors/Committee Members: Chandrasekar, V. (advisor), Notaros, Branislav M. (committee member), Mielke, Paul W. (committee member).

Subjects/Keywords: polarimetric radar; specific differential phase (KDP) estimation; radar network; quantitative precipitation estimation

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APA (6^th Edition):

Chen, H. (2013). Quantitative precipitation estimation for an X-band weather radar network. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/79026

Chicago Manual of Style (16^th Edition):

Chen, Haonan. “Quantitative precipitation estimation for an X-band weather radar network.” 2013. Masters Thesis, Colorado State University. Accessed March 08, 2021. http://hdl.handle.net/10217/79026.

MLA Handbook (7^th Edition):

Chen, Haonan. “Quantitative precipitation estimation for an X-band weather radar network.” 2013. Web. 08 Mar 2021.

Vancouver:

Chen H. Quantitative precipitation estimation for an X-band weather radar network. [Internet] [Masters thesis]. Colorado State University; 2013. [cited 2021 Mar 08]. Available from: http://hdl.handle.net/10217/79026.

Council of Science Editors:

Chen H. Quantitative precipitation estimation for an X-band weather radar network. [Masters Thesis]. Colorado State University; 2013. Available from: http://hdl.handle.net/10217/79026

Colorado State University

2. Martinez, Matthew Thomas. Description and evaluation of the CASA dual-Doppler system.

Degree: MS(M.S.), Electrical and Computer Engineering, 2011, Colorado State University

URL: http://hdl.handle.net/10217/47430

► Long range weather surveillance radars are designed for observing weather events for hundreds of kilometers from the radar and operate over a large coverage domain… (more)

▼ Long range weather surveillance radars are designed for observing weather events for hundreds of kilometers from the radar and operate over a large coverage domain independently of weather conditions. As a result a loss in spatial resolution and limited temporal sampling of the weather phenomenon occurs. Due to the curvature of the Earth, long-range weather radars tend to make the majority of their precipitation and wind observations in the middle to upper troposphere, resulting in missed features associates with severe weather occurring in the lowest three kilometers of the troposphere. The spacing of long-range weather radars in the United States limits the feasibility of using dual-Doppler wind retrievals that would provide valuable information on the kinematics of weather events to end-users and researchers. The National Science Foundation Center for Collaborative Adapting Sensing of the Atmosphere (CASA) aims to change the current weather sensing model by increasing coverage of the lowest three kilometers of the troposphere by using densely spaced networked short-range weather radars. CASA has deployed a network of these radars in south-western Oklahoma, known as Integrated Project 1 (IP1). The individual radars are adaptively steered by an automated system known as the Meteorological Command and Control (MCC). The geometry of the IP1 network is such that the coverage domains of the individual radars are overlapping. A dual-Doppler system has been developed for the IP1 network which takes advantage of the overlapping coverage domains. The system is comprised of two subsystems, scan optimization and wind field retrieval. The scan strategy subsystem uses the DCAS model and the number of dual-Doppler pairs in the IP1 network to minimizes the normalized standard deviation in the wind field retrieval. The scan strategy subsystem also minimizes the synchronization error between two radars. The retrieval itself is comprised of two steps, data resampling and the retrieval process. The resampling step map data collected in radar coordinates to a common Cartesian grid. The retrieval process uses the radial velocity measurements to estimate the northward, eastward, and vertical component of the wind. The error in the retrieval is related to the beam crossing angle. The best retrievals occur at beam crossing angles greater than 30 degrees. During operations statistics on the scan strategy and wind field retrievals are collected in real-time. For the scan strategy subsystem statistics on the beam crossing angels, maximum elevation angle, number of elevation angles, maximum observable height, and synchronization time between radars in a pair are collected by the MCC. These statistics are used to evaluate the performance of the scan strategy subsystem. Observations of a strong wind event occurring on April 2, 2010 are used to evaluate the decision process associated with the scan strategy optimization. For the retrieval subsystem, the normalized standard deviation for the wind field retrieval is used to evaluate the quality of… Advisors/Committee Members: Chandra, Chandrasekar V. (advisor), Notaros, Branislav M. (committee member), Mielke, Paul W. (committee member).

Subjects/Keywords: dual-Doppler; volume targets; signal processing; networked radar

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APA (6^th Edition):

Martinez, M. T. (2011). Description and evaluation of the CASA dual-Doppler system. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/47430

Chicago Manual of Style (16^th Edition):

Martinez, Matthew Thomas. “Description and evaluation of the CASA dual-Doppler system.” 2011. Masters Thesis, Colorado State University. Accessed March 08, 2021. http://hdl.handle.net/10217/47430.

MLA Handbook (7^th Edition):

Martinez, Matthew Thomas. “Description and evaluation of the CASA dual-Doppler system.” 2011. Web. 08 Mar 2021.

Vancouver:

Martinez MT. Description and evaluation of the CASA dual-Doppler system. [Internet] [Masters thesis]. Colorado State University; 2011. [cited 2021 Mar 08]. Available from: http://hdl.handle.net/10217/47430.

Council of Science Editors:

Martinez MT. Description and evaluation of the CASA dual-Doppler system. [Masters Thesis]. Colorado State University; 2011. Available from: http://hdl.handle.net/10217/47430

3. Chobanyan, Elene. Higher order volume/surface integral equation modeling of antennas and scatterers using diakoptics and method of moments.

Degree: PhD, Electrical and Computer Engineering, 2015, Colorado State University

URL: http://hdl.handle.net/10217/166946

► The principal objective of this dissertation is to develop, test, and optimize accurate, efficient, and robust computational methodology and tools for modeling of general antennas… (more)

▼ The principal objective of this dissertation is to develop, test, and optimize accurate, efficient, and robust computational methodology and tools for modeling of general antennas and scatterers based on solutions of electromagnetic integral equation formulations using the method of moments (MoM) and diakoptics. The approaches and implementations include the volume integral equation (VIE) method and its hybridization with the surface integral equation (SIE) method, in two ways. The first way combines the VIE method for dielectric parts and the SIE method for metallic parts of the structure. The second way performs subdivision of the entire structure into SIE domains of different constant permittivities, while modeling the inhomogeneity within each domain by the VIE method and employing different Green's functions, with describing the inhomogeneity within each domain in terms of a perturbation with respect to the background permittivity. The first approach is very suitable for analysis of composite wire-plate-dielectric radiation/scattering structures. The second approach provides a particularly efficient solution to problems involving inhomogineities embedded within high-contrast homogeneous dielectric scatterers. The efficiency of computation is enhanced by applying the diakoptic domain decomposition. In the VIE-SIE diakoptic method, the interior diakoptic subsystems containing inhomogeneous dielectric materials are analyzed completely independently applying the VIE-SIE MoM solver, and the solution to the original problem is obtained from linear relations between electric and magnetic surface-current diakoptic coefficients on diakoptic surfaces, written in the form of matrices. The techniques implement Lagrange-type generalized curved parametric hexahedral MoM-VIE volume elements and quadrilateral MoM-SIE and diakoptic patches of arbitrary geometrical-mapping orders, and divergence-conforming hierarchical polynomial vector basis functions of arbitrary current expansion orders. The hexahedra can be filled with inhomogeneous dielectric materials with continuous spatial variations of the permittivity described by Lagrange interpolation polynomials of arbitrary material-representation orders. Numerical computation is further accelerated by MPI parallelization to enable analysis of large electromagnetic problems. Advisors/Committee Members: Notaros, Branislav M. (advisor), Reising, Steven (committee member), Oprea, Iuliana (committee member), Chandrasekar, V. (committee member), Pezeshki, Ali (committee member).

Subjects/Keywords: electromagnetic analysis; method of moments; volume integral equations; higher order modeling; domain decomposition; numerical techniques

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Chobanyan, E. (2015). Higher order volume/surface integral equation modeling of antennas and scatterers using diakoptics and method of moments. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/166946

Chicago Manual of Style (16^th Edition):

Chobanyan, Elene. “Higher order volume/surface integral equation modeling of antennas and scatterers using diakoptics and method of moments.” 2015. Doctoral Dissertation, Colorado State University. Accessed March 08, 2021. http://hdl.handle.net/10217/166946.

MLA Handbook (7^th Edition):

Chobanyan, Elene. “Higher order volume/surface integral equation modeling of antennas and scatterers using diakoptics and method of moments.” 2015. Web. 08 Mar 2021.

Vancouver:

Chobanyan E. Higher order volume/surface integral equation modeling of antennas and scatterers using diakoptics and method of moments. [Internet] [Doctoral dissertation]. Colorado State University; 2015. [cited 2021 Mar 08]. Available from: http://hdl.handle.net/10217/166946.

Council of Science Editors:

Chobanyan E. Higher order volume/surface integral equation modeling of antennas and scatterers using diakoptics and method of moments. [Doctoral Dissertation]. Colorado State University; 2015. Available from: http://hdl.handle.net/10217/166946

Colorado State University

4. Ruzanski, Evan. Nowcasting for a high-resolution weather radar network.

Degree: PhD, Electrical and Computer Engineering, 2010, Colorado State University

URL: http://hdl.handle.net/10217/45965

► Short-term prediction (nowcasting) of high-impact weather events can lead to significant improvement in warnings and advisories and is of great practical importance. Nowcasting using weather… (more)

▼ Short-term prediction (nowcasting) of high-impact weather events can lead to significant improvement in warnings and advisories and is of great practical importance. Nowcasting using weather radar reflectivity data has been shown to be particularly useful. The Collaborative Adaptive Sensing of the Atmosphere (CASA) radar network provides high-resolution reflectivity data amenable to producing valuable nowcasts. The high-resolution nature of CASA data requires the use of an efficient nowcasting approach, which necessitated the development of the Dynamic Adaptive Radar Tracking of Storms (DARTS) and sinc kernel-based advection nowcasting methodology. This methodology was implemented operationally in the CASA Distributed Collaborative Adaptive Sensing (DCAS) system in a robust and efficient manner necessitated by the high-resolution nature of CASA data and distributed nature of the environment in which the nowcasting system operates. Nowcasts up to 10 min to support emergency manager decision-making and 1-5 min to steer the CASA radar nodes to better observe the advecting storm patterns for forecasters and researchers are currently provided by this system. Results of nowcasting performance during the 2009 CASA IP experiment are presented. Additionally, currently state-of-the-art scale-based filtering methods were adapted and evaluated for use in the CASA DCAS to provide a scale-based analysis of nowcasting. DARTS was also incorporated in the Weather Support to Deicing Decision Making system to provide more accurate and efficient snow water equivalent nowcasts for aircraft deicing decision support relative to the radar-based nowcasting method currently used in the operational system. Results of an evaluation using data collected from 2007-2008 by the Weather Service Radar-1988 Doppler (WSR-88D) located near Denver, Colorado, and the National Center for Atmospheric Research Marshall Test Site near Boulder, Colorado, are presented. DARTS was also used to study the short-term predictability of precipitation patterns depicted by high-resolution reflectivity data observed at microalpha (0.2-2 km) to mesobeta (20-200 km) scales by the CASA radar network. Additionally, DARTS was used to investigate the performance of nowcasting rainfall fields derived from specific differential phase estimates, which have been shown to provide more accurate and robust rainfall estimates compared to those made from radar reflectivity data. Advisors/Committee Members: Chandrasekar, V. (advisor), Jayasumana, Anura P. (committee member), Mielke, Paul W. (committee member), Notaros, Branislav M. (committee member).

Subjects/Keywords: weather radar; weather forecasting; nowcasting; specific differential phase; prediction; Nowcasting (Meteorology); Meteorological satellites; Weather forecasting; Weather radar networks

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Ruzanski, E. (2010). Nowcasting for a high-resolution weather radar network. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/45965

Chicago Manual of Style (16^th Edition):

Ruzanski, Evan. “Nowcasting for a high-resolution weather radar network.” 2010. Doctoral Dissertation, Colorado State University. Accessed March 08, 2021. http://hdl.handle.net/10217/45965.

MLA Handbook (7^th Edition):

Ruzanski, Evan. “Nowcasting for a high-resolution weather radar network.” 2010. Web. 08 Mar 2021.

Vancouver:

Ruzanski E. Nowcasting for a high-resolution weather radar network. [Internet] [Doctoral dissertation]. Colorado State University; 2010. [cited 2021 Mar 08]. Available from: http://hdl.handle.net/10217/45965.

Council of Science Editors:

Ruzanski E. Nowcasting for a high-resolution weather radar network. [Doctoral Dissertation]. Colorado State University; 2010. Available from: http://hdl.handle.net/10217/45965

Colorado State University

5. Fritz, Jason P. Precipitation observations from high frequency spaceborne polarimetric synthetic aperture radar and ground-based radar: theory and model validation.

Degree: PhD, Electrical and Computer Engineering, 2010, Colorado State University

URL: http://hdl.handle.net/10217/44865

► Global weather monitoring is a very useful tool to better understand the Earth's hydrological cycle and provide critical information for emergency and warning systems in… (more)

▼ Global weather monitoring is a very useful tool to better understand the Earth's hydrological cycle and provide critical information for emergency and warning systems in severe cases. Developed countries have installed numerous ground-based radars for this purpose, but they obviously are not global in extent. To address this issue, the Tropical Rainfall Measurement Mission (TRMM) was launched in 1997 and has been quite successful. The follow-on Global Precipitation Measurement (GPM) mission will replace TRMM once it is launched. However, a single precipitation radar satellite is still limited, so it would be beneficial if additional existing satellite platforms can be used for meteorological purposes. Within the past few years, several X-band Synthetic Aperture Radar (SAR) satellites have been launched and more are planned. While the primary SAR application is surface monitoring, and they are heralded as "all weather'' systems, strong precipitation induces propagation and backscatter effects in the data. Thus, there exists a potential for weather monitoring using this technology. The process of extracting meteorological parameters from radar measurements is essentially an inversion problem that has been extensively studied for radars designed to estimate these parameters. Before attempting to solve the inverse problem for SAR data, however, the forward problem must be addressed to gain knowledge on exactly how precipitation impacts SAR imagery. This is accomplished by simulating storms in SAR data starting from real measurements of a storm by ground-based polarimetric radar. In addition, real storm observations by current SAR platforms are also quantitatively analyzed by comparison to theoretical results using simultaneous acquisitions by ground radars even in single polarization. For storm simulation, a novel approach is presented here using neural networks to accommodate the oscillations present when the particle scattering requires the Mie solution, i.e., particle diameter is close to the radar wavelength. The process of transforming the real ground measurements to spaceborne SAR is also described, and results are presented in detail. These results are then compared to real observations of storms acquired by the German TerraSAR-X satellite and by one of the Italian COSMO-SkyMed satellites both operating in co-polar mode (i.e., HH and VV). In the TerraSAR-X case, two horizontal polarization ground radars provided simultaneous observations, from which theoretical attenuation is derived assuming all rain hydrometeors. A C-band fully polarimetric ground radar simultaneously observed the storm captured by the COSMO-SkyMed SAR, providing a case to begin validating the simulation model. While previous research has identified the backscatter and attenuation effects of precipitation on X-band SAR imagery, and some have noted an impact on polarimetric observations, the research presented here is the first to quantify it in a holistic sense and demonstrate it using a detailed model of actual storms observed by ground… Advisors/Committee Members: Chandrasekar, V. (advisor), Jayasumana, Anura P. (committee member), Notaros, Branislav M. (committee member), Mielke, Paul W. (committee member).

Subjects/Keywords: X-band; synthetic aperture radar; precipitation; polarimetry; Precipitation (Meteorology); Radar meteorology; Synthetic aperture radar; Polarimetric remote sensing

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APA (6^th Edition):

Fritz, J. P. (2010). Precipitation observations from high frequency spaceborne polarimetric synthetic aperture radar and ground-based radar: theory and model validation. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/44865

Chicago Manual of Style (16^th Edition):

Fritz, Jason P. “Precipitation observations from high frequency spaceborne polarimetric synthetic aperture radar and ground-based radar: theory and model validation.” 2010. Doctoral Dissertation, Colorado State University. Accessed March 08, 2021. http://hdl.handle.net/10217/44865.

MLA Handbook (7^th Edition):

Fritz, Jason P. “Precipitation observations from high frequency spaceborne polarimetric synthetic aperture radar and ground-based radar: theory and model validation.” 2010. Web. 08 Mar 2021.

Vancouver:

Fritz JP. Precipitation observations from high frequency spaceborne polarimetric synthetic aperture radar and ground-based radar: theory and model validation. [Internet] [Doctoral dissertation]. Colorado State University; 2010. [cited 2021 Mar 08]. Available from: http://hdl.handle.net/10217/44865.

Council of Science Editors:

Fritz JP. Precipitation observations from high frequency spaceborne polarimetric synthetic aperture radar and ground-based radar: theory and model validation. [Doctoral Dissertation]. Colorado State University; 2010. Available from: http://hdl.handle.net/10217/44865

Colorado State University

6. Sahoo, Swaroop. Retrieval techniques and information content analysis to improve remote sensing of atmospheric water vapor, liquid water and temperature from ground-based microwave radiometer measurements.

Degree: PhD, Electrical and Computer Engineering, 2015, Colorado State University

URL: http://hdl.handle.net/10217/166870

To view the abstract, please see the full text of the document. Advisors/Committee Members: Reising, Steven C. (advisor), Notaros, Branislav M. (committee member), Vivekanandan, Jothiram (committee member), Rutledge, Steven A. (committee member).

Subjects/Keywords: radiometry; temperature; atmospheric measurements; water vapor; remote sensing

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Sahoo, S. (2015). Retrieval techniques and information content analysis to improve remote sensing of atmospheric water vapor, liquid water and temperature from ground-based microwave radiometer measurements. (Doctoral Dissertation). Colorado State University. Retrieved from http://hdl.handle.net/10217/166870

Chicago Manual of Style (16^th Edition):

Sahoo, Swaroop. “Retrieval techniques and information content analysis to improve remote sensing of atmospheric water vapor, liquid water and temperature from ground-based microwave radiometer measurements.” 2015. Doctoral Dissertation, Colorado State University. Accessed March 08, 2021. http://hdl.handle.net/10217/166870.

MLA Handbook (7^th Edition):

Vancouver:

Sahoo S. Retrieval techniques and information content analysis to improve remote sensing of atmospheric water vapor, liquid water and temperature from ground-based microwave radiometer measurements. [Internet] [Doctoral dissertation]. Colorado State University; 2015. [cited 2021 Mar 08]. Available from: http://hdl.handle.net/10217/166870.

Council of Science Editors:

Sahoo S. Retrieval techniques and information content analysis to improve remote sensing of atmospheric water vapor, liquid water and temperature from ground-based microwave radiometer measurements. [Doctoral Dissertation]. Colorado State University; 2015. Available from: http://hdl.handle.net/10217/166870

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