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 50 for “"Updraft"”.
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A kinematic model to study the distribution of precipitation in a cumulus updraft.
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Meteorology, 1973.
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THE OBSERVED VARIATION OF COHERENT UPDRAFT OBJECTS WITH HEIGHT IN THE CONVECTIVE BOUNDARY LAYER
… analyze the properties of ~120,000 coherent CBL updrafts recorded with a network of five Doppler lidars in Oklahoma, USA on days with clear and cumulus topped boundary layers. We present the composite evolution of these updraft objects as a function of height, which reveal a mixture of plume-like …
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Estimating midlevel updraft characteristics and severe weather intensity through the lens of overshooting tops
… relates strongly to the area of the associated updraft core within the middle troposphere. Observational support of such overshooting top area (OTA) – updraft relationships was found in this thesis using coincident observations of (overshooting tops) OTs and updrafts collected in three cases …
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Controls of updraft size, cold pool characteristics, and potential tornado intensity in supercell thunderstorms
… interconnections between convection initiation, updraft structure, and subsequent cold pool generation are not well understood. This has become particularly relevant with ongoing efforts to introduce cold pool processes in convective parameterization schemes. Here, the structure of supercell …
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Analysis and design of a new updraft free-exit-flow low-head hydropower turbine system
<p>A new updraft free-exit-flow low-head hydropower turbine system is designed to enhance tailrace water quality, to minimize fish mortality in turbine flow passage, to improve turbine mechanical performance, and to reduce costs and time of hydropower development. This study applies the …
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Understanding tornado intensity in supercells and quasi-linear convective systems
… a theoretical framework linking tornadic storm updraft characteristics to tornado intensity is further explored. An application of Kelvin’s circulation theorem to pre-tornadic and tornadic circulations shows that initial tornadic circulations are necessarily constrained by the circulation of the …
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Insights into tornadogenesis and tornado dynamics from idealized simulations
… pool to the intensification by the low-level updraft is systematically evaluated in CM1. It is found that small changes in both of these parameters can cause a bifurcation between the tornadic and nontornadic cases, demonstrating the nonlinearity of tornadogenesis. The relative importance of …
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Numerical simulations of mesoscale convective systems: techniques for comparison with observations and a high resolution analysis of flow patterns in the convective region and transition zone of a simulated mcs
… were found to still affect the convective updrafts in addition to their immediate environment, including the horizontal velocity and temperature fields. The convective updraft was found to be highly unsteady, frequently changing between one or two coherent primary updrafts and a series of …
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Dual-Polarization Radar Characteristics of Convection in Hawaii during HERO
… As it passed to the west of the radar, a 7 m s-1 updraft was observed at the center. For the sea-breeze storm, the convective lifecycle from initiation through dissipation was studied for a single cell. From convective initiation, it took 15-19 minutes to reach the convective peak, and another 6 …
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Comparison of positive and negative cloud-to-ground lightning dominant storms in three regions of the United States
… storms had a much larger volume of >10 m s-1 updraft than the -CG dominant storms, which may contribute to the production of the inverted charge structure. The +CG dominant storms also had larger graupel echo volumes, consistent with the larger updraft volumes.
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An investigation of the development of supercells in the Indiana and Ohio tornado outbreak of 24 August 2016 using a WRF model simulation
… indicate that parcels entering the multicellular updrafts before 1530 UTC originate above 1 km, meaning that the convection is elevated. As diurnal heating progresses, more near-surface parcels enter the multicellular updrafts, each of which move atop convective outflow and weaken. Since nearly …
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Internal vs. External Forcings in Supercell Interactions and Their Impact on Storm Morphology and Intensity
… flank gust front, propagate toward the main updraft, and are stretched immediately prior to mesocyclogenesis events. These discrete rotation centers are approximately one kilometer deep and would most often be unobserved by operational radar. The external forcing associated with the initial …
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Conditions in architecture
… Limit by Robert Penn Warren I saw the hawk ride updraft in the sunset over Wyoming. It rose from coniferous darkness, past gray jags Of mercilessness, past whiteness, into the gloaming Of dream spectral light above the last purity of snow-snags. There-west-were the Tetons. Snow peaks would soon …
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Free convection and turbulent fluxes over complex terrain
… as the LES model showed the presence of coherent updraft structures in the developing early-morning convective boundary layer (CBL) in the Kinzig valley (Black Forest) during FCCs. Spectral analysis of the EC data in these situations indicated the existence of large-eddy turbulent scales – typical …
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A theory of the mesoscale organization of moist convection and the associated vertical momentum transport
… force induced by interactions between the updraft and the environmental wind. The orientation, aspect ratio, phase speed and size of the organized convection are determined. These quantities depend on the vertical wind-shear and the stratification. GATE, ARM, EMEX, SCSMEX, and TOGA COARE …
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Effects of Microphysical Parameterizations and Drop Breakup on Supercells and Supercell Cold Pools.
… High amounts of rain are present near the updraft of the Morrison parameterizations in the area where the strongest part of the cold pool resides. These high precipitation regions are caused by hail melting and rain evaporating. The evolution of rain, especially, is in part controlled by …
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Effects of environmental shear and buoyancy on simulated supercell interactions
… alignment have more vorticity centers reach an updraft where they are stretched and intensi ed. With re- spect to storm mode, higher buoyancy produced less classic supercells while higher shear produced more classic supercells. High precipitation supercells were favored with two-cell simulations …
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Storm mergers and their role in tornado genesis during the 2011 Joplin storm
… intensification of the parent rotating updraft (mesocyclone) and tornadic vortex in the 22 May 2011 Joplin, MO case. This case was noted for the rapid evolution of the storm from tornado formation (tornadogenesis) to peak intensity in relation to the merging of cells in the rear-flank …
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Emissions, efficiency, and combustion chamber conditions of a smokeless, hand-fired coal heater
… lower than those found using identical coals in updraft stoves. The overall efficiency of the unit was determined to range from 54 to 60%. The sensible energy losses were found to represent the majority of the total energy losses.
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