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You searched for subject:(Spectral tools). Showing records 1 – 2 of 2 total matches.

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1. Garbanzo-Salas, Marcial. High resolution tropospheric studies with an MST type radar.

Degree: 2015, University of Western Ontario

Applications and results of a variety of studies carried out with the Costa Rican VHF profiler radar are included. This radar is unique because of the wide frequency bandwidth available (5 MHz). During the developing stages of the wind profiler radar new techniques of processing and radar engineering were used. A thorough analysis of a data-dependent method (Capon's) commonly used in radar was carried out. This method is analyzed based on a reference established by Fourier theory. Disadvantages of using data-dependent methods with small filters were found. A small filter size will cause Capon's method to underestimate the number of spectral peaks when compared to using a larger filter size. The understimation will occur even when the filter size is larger than the number of peaks. When used to estimate a known Gaussian spectrum, Capon's method understimated the spectral width independently of the filter size. The backscattered signal measured in radars is the convolution of the transmitted signal with the atmospheric profile of scatterers. The convolution integral model was used to calculate radar backscatter. The implementations were created to simulate radar backscatter using the transmitted signal and the electric permittivity profile of the atmosphere. Tests with realistic physical conditions were carried out to validate the model and verify the implementation. Appropriate range location and Doppler velocites were obtained from simple simulations in one, two and three dimensions. The convolution engine was later used along with a mathematical representation of atmospheric scatterers to study the simulated radar echoes. Correct radial velocites were obtained along with realistic radar effect like the beam broadening effect. A Large eddy simulation (LES) model was used to simulate a full-physics atmosphere. The LES code follows the fluid dynamics equations. The simulated LES atmosphere was used to calculate the electric permittivity from atmospheric variables. A radar simulation involving the convolution of this electric permittivity profile and the radar pulse allowed us to simulate a radar inside the simulated atmosphere. The initial conditions of the simulation created a clear planetary boundary layer as well as a region of shear instabilities in the upper heights. Both regions generated turbulence during the simulation and allowed the radar simulation to measure it satisfactorily. Anisotropy was observed in the results when comparing vertical beam data to tilted beam data as usually observed in real measurements. A long term experiment was carried out in Costa Rica to gather information about the tropical atmosphere. This was the first time this type of experiment was carried out in Costa Rica. The information provided a clear perspective of the phenomena found in the lower troposphere. Among others, the planetary boundary layer (PBL), thin layers, isolated patches of turbulence, oscillations and convective events were detected. The presence of layers over Costa Rica is well defined; during the dry season…

Subjects/Keywords: Wind profiler; wide bandwidth; deconvolution; radar simulation; large eddy simulation; spectral tools; Other Physics

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

APA (6th Edition):

Garbanzo-Salas, M. (2015). High resolution tropospheric studies with an MST type radar. (Thesis). University of Western Ontario. Retrieved from https://ir.lib.uwo.ca/etd/3312

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Garbanzo-Salas, Marcial. “High resolution tropospheric studies with an MST type radar.” 2015. Thesis, University of Western Ontario. Accessed January 25, 2020. https://ir.lib.uwo.ca/etd/3312.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Garbanzo-Salas, Marcial. “High resolution tropospheric studies with an MST type radar.” 2015. Web. 25 Jan 2020.

Vancouver:

Garbanzo-Salas M. High resolution tropospheric studies with an MST type radar. [Internet] [Thesis]. University of Western Ontario; 2015. [cited 2020 Jan 25]. Available from: https://ir.lib.uwo.ca/etd/3312.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Garbanzo-Salas M. High resolution tropospheric studies with an MST type radar. [Thesis]. University of Western Ontario; 2015. Available from: https://ir.lib.uwo.ca/etd/3312

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation


Massey University

2. Pullanagari, Rajasheker Reddy. Proximal sensing techniques to monitor pasture quality and quantity on dairy farms.

Degree: PhD, Soil Science, 2011, Massey University

Regular and timely measurements of pasture quality and quantity allow dairy farmers to make effective decisions ensuring an adequate supply of nutrients to animals, efficient utilization of pasture, manipulation of stocking rates, management grazing intervals, and optimisation of input resources (e.g. nitrogen fertilisers) which results in more economic, environmentally aware, sustainable grazing systems. The objectives of this research were to investigate the potential of proximal sensing tools to estimate pasture quality parameters (crude protein, CP; acid detergent fibre, ADF; neutral detergent fibre, NDF; ash, dietary cation-anion difference, DCAD; lignin, lipid, metabolisable energy, ME and organic matter digestibility, OMD) in mixed pastures. Three proximal sensors, ASD FieldSpec® Pro FR spectroradiometer (hyperspectral), Cropscan™ (multispectral) and Crop Circle™ (multispectral), were employed in this study. In the hyperspectral study, the spectral reflectance measurements of pasture samples were acquired using an ASD FieldSpec® Pro FR spectroradiometer which has a spectral range of 350-2500 nm and attached with canopy pasture probe (CAPP) to ensure ambient light conditions. The acquired spectral data were pre-processed by various procedures: spectral averaging, smoothing and derivative transformation, then partial least squares regression was applied to regress against the corresponding measured values. The regression model was validated with an external dataset to evaluate the reliability and robustness of the model. The performance of both calibration and validation models were more or less similar. The validation model predicted the pasture quality parameters CP, ADF, NDF, ash, DCAD, lignin, ME and OMD with reasonable accuracy (0.65 ≤ R2 ≤ 0.83; 1.70 ≤ RPD ≤ 2.48; 0.64 ≤ NSE ≤ 0.83) and the lipid was predicted with lower accuracy (R2-0.55; RPD-1.44; NSE-0.50). Cropscan relies on sunlight for its energy source and measures reflectance in 16 broad wavebands; it was evaluated for its potential to assess pasture quality parameters that are collected in one season. The relationship between spectral reflectance measured using the Cropscan and pasture quality parameters were established using single wavebands, new vegetation indices and stepwise multiple linear regression (SMLR) and the models were validated with an external dataset. Of all the models, the new non-linear new combination of RDVI index models were performed satisfactory results (0.65 ≤ R2 ≤ 0.85) for predicting CP, DCAD, ME and OMD. CP, ash, DCAD, lipid, ME and OMD were estimated with moderate accuracy (0.60 ≤ R2 ≤ 0.80) using the SMLR model. The Cropscan instrument was also used to test the potential for predicting pasture quality in different seasons (autumn, spring and summer). Improved accuracy was observed with season-specific models as compared to the combined season dataset models. A three channel active optical sensor, Crop Circle™ was used to estimate herbage biomass and standing crude protein (SCP) using various indices. The results…

Subjects/Keywords: Pasture quality; Proximal sensing tools; Spectroradiometer; Reflectance spectroscopy; Spectral reflectance; Pasture analysis; Optical sensors

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

APA (6th Edition):

Pullanagari, R. R. (2011). Proximal sensing techniques to monitor pasture quality and quantity on dairy farms. (Doctoral Dissertation). Massey University. Retrieved from http://hdl.handle.net/10179/3695

Chicago Manual of Style (16th Edition):

Pullanagari, Rajasheker Reddy. “Proximal sensing techniques to monitor pasture quality and quantity on dairy farms.” 2011. Doctoral Dissertation, Massey University. Accessed January 25, 2020. http://hdl.handle.net/10179/3695.

MLA Handbook (7th Edition):

Pullanagari, Rajasheker Reddy. “Proximal sensing techniques to monitor pasture quality and quantity on dairy farms.” 2011. Web. 25 Jan 2020.

Vancouver:

Pullanagari RR. Proximal sensing techniques to monitor pasture quality and quantity on dairy farms. [Internet] [Doctoral dissertation]. Massey University; 2011. [cited 2020 Jan 25]. Available from: http://hdl.handle.net/10179/3695.

Council of Science Editors:

Pullanagari RR. Proximal sensing techniques to monitor pasture quality and quantity on dairy farms. [Doctoral Dissertation]. Massey University; 2011. Available from: http://hdl.handle.net/10179/3695

.