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Articles 1 - 8 of 8
Full-Text Articles in Physical Sciences and Mathematics
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 …
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
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.
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.