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.
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Showing 1 to 20 of 93 for “"Optical Depth"”.
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Analysis of Aerosol Optical Depth for South Korea
… pollution levels. This research analyzes aerosol optical depth (AOD), a measurement of aerosols present in the atmosphere, for South Korea, taking special interests in urban factors and topography. Through analyses using Matlab, a correlation between the AOD, urban factors, and topography was …
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Multispectral optical depth measurements in post-detonation high explosive fireballs
Temporally and spectrally resolved optical depth measurements were made in post-detonation fireballs from five different high explosives. PETN, HMX-based PBXN-5, RDX, an 80% RDX/20% aluminum mixture, and PETN-based Primasheet 1000 explosives were detonated in a 2.18L explosive test chamber. Charges …
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DESIGN OF A LOW-COST PORTABLE HANDHELD SPECTROMETER FOR AEROSOL OPTICAL DEPTH MEASUREMENTS
… handheld field instrument that measures aerosol optical thickness. The challenges associated with designing a low-cost, durable handheld system with highly sensitive electronics, which is capable of direct-sun measurements, are investigated. The thesis work can be summarized as follows. First, …
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Aerosol Optical Depth And Its Relationship To Radar Derived Precipitation In Mali, West Africa
… if a relationship exists between Aerosol Optical Depth (AOD) and radar-derived precipitation in Mali, a country located in West Africa. Precipitation parameters derived from 2006, 2007 and 2008 C-band radar measurements are compared against Noon to 2 p.m. averaged AOD measurements. The AOD …
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Evaluating The Impact Of Above-Cloud Aerosols On Cloud Optical Depth Retrievals From Modis
… Imaging Spectroradiometer (MODIS) cloud optical depth (COD) retrievals (visible and shortwave infrared), the impacts of above-cloud absorbing aerosols on the standard COD retrievals are evaluated. For fine-mode aerosol particles, aerosol optical depth (AOD) values diminish sharply from …
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Investigating Elevated Aqua Modis Aerosol Optical Depth Retrievals Over The Mid-Latitude Southern Oceans
<p>A band of elevated aerosol optical depth (AOD) over the mid-latitude Southern Oceans has been identified in some passive satellite-based aerosol datasets such as Moderate Resolution Imaging SpectroRadiometer (MODIS) and Multi-angle Imaging SpectroRadiometer (MISR) products. In this study, Aqua …
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40 Years Global Estimation of Aerosol Optical Depth Profiles Using MISR and TOMS Aerosol Products
… Accordingly, different parameters like aerosol optical depth, aerosol index, angstrom exponent, etc., are used to represent the different aspects of their behavior. Several satellite missions have tried to characterize aerosol particles. However, these data records are not complete in space and …
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Aerosol optical depth retrievals from high-resolution commercial satellite imagery over areas of high surface reflectance
… aerosol characterization. Current aerosol optical depth retrieval methods typically fail over areas with high surface reflectance, such as urban areas and deserts, since the upwelling radiance due to scattering by aerosols is small compared to the radiance resulting from surface reflection. …
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A Geographical Comparison of the Relationship Between Aerosol Optical Depth and Fine Particulate Matter in Indiana
This study looked at the time period of June through mid-October, 2013, based on the results of earlier studies that the strongest correlation between the PM2.5 and AOD data sets occurs during the summer and fall. Terra satellite data was used in this study due to availability of images for the …
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Increases and decreases in the fine mode fraction of aerosol optical depth with increasing relative humidity
… Imaging SpectroRadiometer) to the Aerosol Optical Depth (AOD) is correlated to the AERONET (Aerosol Robotic Network) fine mode fraction of AOD. According to this thesis the contribution of particles having radius <= 0.7 um to the measured AOD can either increase or decrease with increasing …
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Comparisons of an aerosol transport model with a 4-year analysis of summer aerosol optical depth retrievals over the Canadian Arctic
Cette étude compare des épaisseurs optiques d’aérosols (AOD) à 5 stations arctiques d’AEROCAN (AERONET), obtenues d’une part à l’aide de l’algorithme d'inversion de Dubovik appliqué à des mesures in situ, et d’autre part du modèle de transport chimique (GEOS-Chem : Goddard Earth Observing Système …
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Satellite Cloud Detection With Shortwave Channels: Algorithms, MISR Applications, and Three-Dimensional Radiative Effects
… their consequences on cloud fraction and aerosol optical depth retrieval. The results showed that 3-D radiative effects lead to overlaps between the distributions of clear and cloudy pixels through channeling, leakage, shadowing and cloud-surface interaction pathways. Due to this fact, perfect …
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The HI Lyman-alpha opacity at redshift 2.7 < z < 3.6
… suggest that the HI Lyman-alpha effective optical depth, τ_eff, decreases with decreasing redshift, which is primarily due to the expansion of the Universe. However, some studies find a smaller value of the effective optical depth than expected at the specific redshift z~3.2, possibly …
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CORRELATED PHOTON PAIRS AND MULTIPHOTON STATES FROM A COLD ATOMIC ENSEMBLE
… wavelengths of 780 nm and 795 nm in an optically dense cold <sup>87</sup>Rb ensemble. The source is based on a spontaneous four-wave mixing process implemented in a double-Λ energy-level configuration. By systematically varying the pump intensities, detunings, and optical depth, …
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The kinematic and thermal Sunyaev-Zel'dovich effects as probes of cosmology and astrophysics
… template, I measure the average central optical depth of the cluster sample. I compare the extracted signal to simulations and find good agreement with respect to the signal-to-noise, the constraint on the optical depth, and the corresponding gas fraction. I next study the potential of …
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Interferometric Mapping of Magnetic Fields in Star -Forming Regions
… toward the regions with high density and/or high optical depth.
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Microwave remote sensing of water in the soil - plant system
… 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 …
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Emergence of Collective Light Scattering in Atomic <sup>87</sup>Rb Samples
… the atomic samples are increasing in density and optical depth. As such, the spectroscopic properties of the atomic media are modified due to interactions among the particles in the ensemble. We report investigation of near-resonance light scattering from a cold atomic sample of 87Rb. Initially …
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A new technique to find both real and imaginary index of refraction of atmospheric aerosols from clear sky radiance measurements.
… that the aerosol size distribution, Rayleigh optical depth, aerosol optical depth, surface albedo, and preferably the surface anisotropic characteristics be known from correlative measurements. The calculated optimal radiance ratio, which is the ratio of maximum sensitivity to the index being …
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