Browsing OU - Theses by Author "Cavallo, Steven"
Now showing items 1-20 of 20
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A 13-year Trajectory-Based Analysis of Convection-Driven Changes in Upper Troposphere Lower Stratosphere Composition over the United States
Tinney, Emily (2020-12-18)Moist convection frequently reaches the tropopause and alters the distribution and concentration of radiatively important trace gases in the upper troposphere and lower stratosphere (UTLS), but the overall impact of ... -
60°S-62°S Witnessed a Shift Pattern of Southern Ocean Boundary Layer Aerosols and CCN
Niu, Qing (2021)The Southern Ocean (SO), dominated by high surface wind speeds associated with frequent cyclones, is the most pristine environment on Earth, providing a natural laboratory to study the correlation of marine boundary layer ... -
A comparison of microphysical parameterization sensitivities in three comma-head snow events and evaluation of scheme solutions with PIREPs
Cassady, Kristen (2013)Numerical model experiments are conducted to assess how aircraft icing forecasts are affected by the choice of microphysical parameterization, with respect to the presence of supercooled liquid water (SLW). Select winter ... -
Atmospheric Conditions Preceeding Very Rapid Sea Ice Loss Events
Frank, Madeline Clark (2019)Even though the observed amplified warming trend in the Arctic region is well-established in theory through climate feedbacks and reproduced in global climate model projections, the same global climate models underestimate ... -
Characteristics and Lifecycles of Anticyclonic Tropopause Polar Vortices
Burzdak, Joseph (2023-05-12)Tropopause polar vortices (TPVs) are sub-synoptic, long-lived, closed circulation features located in the upper-troposphere and lower-stratosphere region. Although TPV circulations can be cyclonic or anticyclonic, most ... -
Characteristics of Tropopause Polar Vortices Based on Observations Over The Greenland Ice Sheet
Borg, Sarah (2018-12-14)Tropopause Polar Vortices (TPVs) are long-lived, coherent vortices that are identified by closed material contours of potential temperature on the dynamic tropopause. They are characterized by PV anomalies that spend most ... -
A Comparative Convective Study Between the Ensemble Kalman Filter and the Local Particle Filter Using the Gridpoint Statistical Interpolation System
McAuliffe, Joel (2020-07-30)The localized particle filter (LPF) is a recent advance in ensemble data assimilation for numerical weather prediction. Derived from the original particle filter used for highly nonlinear state variables, the LPF incorporates ... -
A Comparison of Hybrid-4DEnVar and Hourly Hybrid-3DEnVar Assimilation of Tail Doppler Radar Observations on the Prediction of Rapidly Evolving Hurricanes
Davis, Benjamin (2019-08-01)Beginning in the summer of 2017 the National Weather Service upgraded the operational Hurricane WRF (HWRF) to a continuously cycled Gridpoint Statistical Interpolation (GSI) based, 6-hourly, Hybrid 3-dimensional (3D) ... -
Evaluation of the experimental warn-on-forecast system and WoF-hybrid 3DEnVar system on short-term forecasts for 2021 real-time cases
Carpenter, Noah (2022-12-16)Over the last few decades, it has become more important than ever to provide accurate forecasts for severe hazards that have become more common due to climate change effects. Over this time, several forecasting experiments ... -
Explainable Frontal Boundary Predictions for Applications in Operational Environments
Justin, Andrew (2024-05-10)Frontal boundaries drive many high-impact weather events around the globe. Identifying fronts through various thermodynamic fields increases predictability of hazardous weather phenomena. Frontal analysis is still primarily ... -
Impact of data assimilation and model physics on the predictability of the 2012 Great Arctic Cyclone
Chen, Zhihong (2022-08-04)Impact of data assimilation and model physics on the predictability of the 2012 Great Arctic Cyclone A case study of the Great Arctic Cyclone 2012 (AC12) is used to understand the role of initial condition errors and model ... -
Investigating Arctic Cyclone-Tropopause Polar Vortex Interactions with Observing System Simulation Experiments
Bray, Matthew (2023-05-12)Tropopause polar vortices (TPVs) are upper-level cyclonic circulations that are common in high latitudes. TPVs most directly impact weather at the surface by providing baroclinic forcing for the development of Arctic ... -
Large Scale and Local Influences on the Occurrence and Maintenance of Liquid Bearing Clouds over the Greenland Ice Sheet
Edwards-Opperman, Jonathan (2016)Arctic liquid bearing clouds (LBCs) have a large impact on the surface radiation and cryospheric mass budgets. Their effect on the surface radiation budget is a combination of two competing processes. First, they can ... -
A Multi-Resolution Ensemble Hybrid 4DEnVar with Variable Ensemble Sizes to Improve Global and Tropical Cyclone Track Numerical Prediction
Jones, Erin (2022-05)One challenge associated with ensemble-based data assimilation (DA) is the quantitative estimation of the background error covariances. In the current global operational DA system, a reduced resolution background ensemble ... -
Scale-dependent Inflation for Multiscale Ensemble based Data Assimilation
Xu, Naicheng (2023-12-15)The degree of the background ensemble deficiency, often manifested as ensemble underdispersion, can vary at different scales in the ensemble-based data assimilation. This study develops the new scale-dependent inflation ... -
Strengths and Limitations of NSSL's Experimental Warn-on-Forecast System for Ensembles in Forecasting Cyclic Mesocyclogenesis
Britt, Kelsey (2018-12-14)Cyclic mesocyclogenesis is the process by which a supercell produces multiple mesocyclones with similar life cycles. Supercells that exhibit cyclic mesocyclogenesis (i.e. cyclic supercells) have the potential to produce ... -
Structure of tropopause polar vortices represented from the atmospheric profiles of satellite observations
Pajela, Ryan (2022-12-16)Tropopause polar vortices (TPVs) are sub-synoptic tropopause disturbances commonly found poleward of the polar jet stream. Their roles in cyclogenesis and linkages to mid-latitude weather make them relevant to the improvement ... -
Supercell Predictability: Exploring Ensemble Sensitivity to Initial Condition Spread
Flora, Montgomery (2017-05-12)The sensitivity of full-physics ensemble forecasts of supercells to initial condition (IC) uncertainty is investigated. The motivation for the study largely stems from the NOAA Warn-on-Forecast (WoF) program, where the ... -
Synoptic and Local Influences on a Summertime, Long-Lived, Mixed-Phase Cloud Event Over Summit, Greenland
Row, Mallory (2016-08-12)Long-lived, Arctic mixed-phase clouds play a crucial role in modulating the surface energy balance over the Greenland Ice Sheet. However, due to temporally and spatially inconsistent observations, little is known about the ... -
Verification of 10-Meter Wind Forecasts from NSSL-WRF in Predicting Severe Wind-Producing MCSs
Milne, Jeffrey (2016-12-16)Predicting convective winds associated with mesoscale convective systems (MCSs) remains a major challenge for operational severe weather forecasters. To assess the performance of the Weather Research and Forecasting Model ...