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Articles 1 - 14 of 14
Full-Text Articles in Physical Sciences and Mathematics
Interactions Between Tropical Cyclones And The Midlatitude Waveguide: Downstream Impacts And The Role Of Convective Processes, Kevin Prince
Interactions Between Tropical Cyclones And The Midlatitude Waveguide: Downstream Impacts And The Role Of Convective Processes, Kevin Prince
Theses and Dissertations
Significant amplification to the waveguide can occur when a recurving tropical cyclone (TC) interacts with the midlatitude flow, leading to significant downstream impacts. To this point in time, TC-midlatitude waveguide interactions have been conceptualized as primarily being driven by large-scale processes, with convective-scale contributions having been parameterized or neglected. This three-part study diagnoses the impact TC-midlatitude waveguide interactions have on the intensity evolution of downstream TCs and the role convective-scale processes play in TC-midlatitude waveguide interactions. Recurving TCs in both the North Atlantic and western North Pacific basins frequently interact favorably with upstream troughs, where a favorable interaction entails the …
A Mesonet-Based Analysis Of Severe Convective Winds In West Texas., Quint Long
A Mesonet-Based Analysis Of Severe Convective Winds In West Texas., Quint Long
Electronic Theses and Dissertations
Multiple studies have investigated the occurrence of severe convective-related winds and have increased our understanding of the forces driving severe winds and their spatial and temporal patterns. Data for these studies have come from airport stations maintained by the National Weather Service. Their standardization across the United States makes them ideal for research, but they are limited in their distribution. This study aims to create a similar climatology of severe surface level winds using a mesoscale network (“mesonet”). Like their ASOS (Automated Surface Observing System) and AWOS (Automated Weather Observing System) counterparts, these stations are standardized and well maintained. This …
A Temporal Examination Of The Connections Between Convective Available Potential Energy And Convective System Development, Chad A. Small
A Temporal Examination Of The Connections Between Convective Available Potential Energy And Convective System Development, Chad A. Small
Dissertations and Theses
In 1983, the World Climate Research Programme launched its first project: the International Satellite Cloud Climatology Project (ISCCP). While the ISCCP has succeeded in many of its cataloging and analytical goals, one of its flagship products, the Convection Tracking (CT) Database does not contain certain environmental parameters that are essential in understanding how, and when, convection is initiated or intensified. The development of mesoscale convection – notably, convective systems (CS) – is also largely dependent on parameters like convective available potential energy (CAPE) which the ISCCP CT Database does not record. By tying information on CAPE to CS, discoveries in …
The Sensitivity Of Convection To Boundary Layer Parameterization In Hurricanes Harvey And Irma 2017, Dylan Card
The Sensitivity Of Convection To Boundary Layer Parameterization In Hurricanes Harvey And Irma 2017, Dylan Card
Legacy Theses & Dissertations (2009 - 2024)
Tropical cyclones (TCs) pose a significant threat to life and property, and exhibit many severe weather hazards as they make landfall, such as storm surge, strong winds, flooding rains, and tornadoes. TC convection is associated with nearly all of these hazards, which can extend hundreds of kilometers inland; thus, understanding the characteristics and organization of convective cells is important to mitigating risk. Observational studies have noted that TC convection tends to organize downshear and that rotating thunderstorms tend to occur in the downshear-right quadrant of the TC. Modeling studies have also shown that convective cells tend to form upshear right …
A Revised Technique For Measuring Vertical Velocity Using Dropsondes, Timothy Connor Nelson
A Revised Technique For Measuring Vertical Velocity Using Dropsondes, Timothy Connor Nelson
Legacy Theses & Dissertations (2009 - 2024)
The earliest iterations of dropsondes in the 1960's obtained vertical velocity by measuring the geometric fall speed of the dropsonde and the true airspeed (TAS) of the dropsonde from a pitot-static. The vertical velocity errors from this methodology were claimed to be ±1 m s-1. Subsequent dropsonde iterations used various forms of the drag force equation to obtain vertical velocity. The accuracy of these drag force-based measurements, however, are also quite large at ±1–2 m s-1. In this dissertation, an attempt is made to improve vertical velocity errors by revisiting and revising the pitot-static-derived TAS methodology on the eXpendable Digital …
A New Analysis Of The Gálvez-Davison Index For Convective Forecasts In Northern Africa, Gabriel D. Donndelinger
A New Analysis Of The Gálvez-Davison Index For Convective Forecasts In Northern Africa, Gabriel D. Donndelinger
Theses and Dissertations
Severe wind gusts and thunderstorms have been difficult to forecast in Africa. Traditional convective forecast tools (e.g. Total Totals Index, Lifted Index, K Index (KI) and Convective Available Potential Energy) do not accurately portray potential for thunderstorms in Africa. This research effort used the Gálvez-Davison Index (GDI), a convective index created for the tropics, and assess its applicability to northern Africa. GDI was produced for the Caribbean and Central America, and utilized temperature, moisture, mid-level stability, dry air entrainment and an elevation factor to calculate convective potential. In this research, GDI and KI were calculated using Global Forecast System (GFS) …
Tropical Cyclone Rapid Intensification In Environments Of Upper-Tropospheric Troughs : Environmental Influences And Convective Characteristics, Michael Fischer
Tropical Cyclone Rapid Intensification In Environments Of Upper-Tropospheric Troughs : Environmental Influences And Convective Characteristics, Michael Fischer
Legacy Theses & Dissertations (2009 - 2024)
Intensity forecasts for tropical cyclones that undergo a period of rapid intensification are particularly susceptible to large errors. For those storms that interact with an upper-tropospheric trough, tropical cyclone intensity forecasts are complicated, as upper-tropospheric troughs can provide unique intensification mechanisms, but are often associated with unfavorable environmental conditions. Although tropical cyclones in environments with nearby upper-tropospheric troughs are associated with lesser intensification rates than tropical cyclones in environments devoid of upper-tropospheric troughs, some tropical cyclone--trough interactions are associated with a period of rapid intensification. This dissertation utilizes reanalysis output, satellite observations, and ensemble modeling simulations to understand whether rapid …
What Affects The Phase Speed Of Madden-Julian Oscillation Convection, Robert Setzenfand
What Affects The Phase Speed Of Madden-Julian Oscillation Convection, Robert Setzenfand
Legacy Theses & Dissertations (2009 - 2024)
The Madden-Julian Oscillation (MJO) is the main source of convective and circulation variability on intraseasonal timescales and planetary spatial scales within the tropics. Although the phase speed of the MJO convective envelope is often stated as 5 m s–1, MJO events that occur over the Indo-Pacific warm pool can have a range of phase speeds. This study uses a wavelet to identify MJO convective events with specified phase speeds in a satellite-derived outgoing longwave radiation (OLR) dataset during boreal winter. The wavelet-filtered OLR index is then regressed against basic meteorological variables to extract information about MJO events or signals propagating …
Influence Of Lightning-Producing Convection On Tropical Cyclone Intensity Change, Stephanie Stevenson
Influence Of Lightning-Producing Convection On Tropical Cyclone Intensity Change, Stephanie Stevenson
Legacy Theses & Dissertations (2009 - 2024)
Lightning observations in tropical cyclones (TCs) over the ocean are a recent advance- ment, and while many studies have noted relationships between lightning and TC intensity change, the relationships are not consistent. This dissertation aims to understand the com- plexities of the relationships between lightning and TC intensity change, and associate the relationships to storm kinematic, thermodynamic, and microphysical processes.
Convective Transport Of Tropical Marine Boundary Layer Species Into The Upper Troposphere And Relation To Species Lifetime: In Situ Measurements And Global Model Simulation, Sofia M. Chelpon
Dissertations and Theses
This study investigates the influence of tropical deep convection on distribution of trace gasses in the tropical upper troposphere (UT) using data from the Convective Transport of Active Species in the Tropics (CONTRAST) Experiment conducted over the tropical western Pacific during January and February of 2014. Fifty-five chemical species measured during the CONTRAST campaign are analyzed with lifetimes ranging from less than a day to several years. The vertical profiles of these species suggest that they fall into three main groups delineated by their lifetime: 1) very long-lived trace gases demonstrating a nearly constant vertical structure, 2) intermediate lifetime species …
Dry Air, Midlevel Flow, And The Persistence Of Deep Convection In Atlantic Tropical Disturbances, Charles Helms
Dry Air, Midlevel Flow, And The Persistence Of Deep Convection In Atlantic Tropical Disturbances, Charles Helms
Legacy Theses & Dissertations (2009 - 2024)
An analysis of dropsonde-observed relative humidity in the Tropical Storm Gabrielle (2013) pregenesis disturbance suggests the presence of a layer of dry air that is being advected into the disturbance from the north. The focus of this study is on this and similar dry air layers, termed dry air inflow pathways (DAIPs), that are characterized by unidirectional disturbance-relative flow drawing dry air into a tropical disturbance. It is hypothesized that DAIPs act to prevent the establishment of persistent deep convection by importing midlevel
Characterization Of Tropical Clouds Using Multi-Satellite Observations, Ricardo Anderson
Characterization Of Tropical Clouds Using Multi-Satellite Observations, Ricardo Anderson
Dissertations and Theses
Clouds an important component of the earth-climate system and play a critical role in affecting energy and water cycle of the planet. In particular, tropical convective clouds account for the majority of the precipitation that fall on the Earth's surface. Multiple active satellite missions in recent decade such as TRMM (Tropical Rainfall Measurement Mission), and CloudSat have provided fruitful new insight into the internal structures of these tropical convective clouds. In conjunction with cloud data from ISCCP (International Satellite Cloud Climatology Project), that is based passive remote sensing technology in the visible and infrared spectrum, this allows for a more …
Convectively-Coupled Kelvin Waves Over The Tropical Atlantic And African Regions And Their Influence On Atlantic Tropical Cyclogenesis, Michael John Ventrice
Convectively-Coupled Kelvin Waves Over The Tropical Atlantic And African Regions And Their Influence On Atlantic Tropical Cyclogenesis, Michael John Ventrice
Legacy Theses & Dissertations (2009 - 2024)
High-amplitude convectively coupled atmospheric Kelvin waves (CCKWs) are explored over the tropical Atlantic during the boreal summer. Atlantic tropical cyclogenesis is found to be more frequent during the passage of the convectively active phase of the CCKW, and most frequent two days after its passage. CCKWs impact convection within the mean latitude of the inter-tropical convergence zone over the northern tropical Atlantic. In addition to convection, CCKWs also impact the large scale environment that favors Atlantic tropical cyclogenesis (i.e., deep vertical wind shear, moisture, and low-level relative vorticity).
African Easterly Waves And Convection, Gareth James Berry
African Easterly Waves And Convection, Gareth James Berry
Legacy Theses & Dissertations (2009 - 2024)
In this research the physical mechanisms relating synoptic scale African Easterly Waves (AEWs) and convection are explored using a variety of analysis techniques.