Doctor of Philosophy

dissertationThis dissertation attempts to detail the necessary and sufficient conditions for tropical cyclogenesis; specifically those environmental, convective, and thermodynamic properties that may determine the fate of disturbances with apparent genesis potential. Unlike previous observational case studies which evaluate a few cases with limited spatial and temporal resolution in-situ and satellite data, this study examines 1 2 developing and four nondeveloping cases from recent (since 2005) tropical cyclone field campaigns using dropsonde data from multiple agency aircraft, as well as data from infrared and multiple passive microwave satellite platforms. Results, composited for all developing cases, indicate that the inner core of developing disturbances prior to genesis exhibits a midlevel moisture that is greater than the surrounding environment, high relative humidity, a warm temperature anomaly at upper levels that progressively lowers through genesis, and a cool, dry anomaly at low levels. Likewise, the vertical alignment of the low- and midlevel vorticity centers is necessary for formation. The midlevel moisture content only shows a slight "progressive moistening" during the pregenesis stage, while the total precipitable water does not apparently increase among the cases studied. Consistent with conclusions from previous observational and modeling studies, the cool, dry anomaly and increased static stability at low levels in the composite, perhaps as a result of persistent convective precipitation near the center within 1-3 days of genesis, appears to be a necessary condition for formation; this genesis pathway suggests that an initially stronger midlevel vortex precedes primarily low-level spin-up within a day of formation. Among the convective properties examined using the satellite datasets (raining area, convective intensity, area of intense convection, duration, and proximity), the results suggest that the proximity and duration of precipitation within three degrees of the center are the most important properties for formation. However, the developing cases studied do not exhibit any common distinguishing convective characteristics during the pregenesis stage; not all developing cases exhibit widespread, intense convective episodes, and although some of the cases exhibit their most "favorable" convective episodes (in terms of intensity, area, and proximity to the center) around 30-36 hours prior to formation, in a few cases that episode occurs as many as 3 days before formation

MS

thesisAMMA (African Monsoon Multidisciplinary Analyses Experiment) and its NASA extension, NAMMA, provide an unusually high temporal and spatial resolution dataset over northern Africa and the East Atlantic during August and September 2006. Research flights during NAMMA provide an unprecedented opportunity to utilize aircraft data to look at the vertical wind structure of seven consecutive African easterly waves, both developing and nondeveloping, that passed through the experimental domain in the East Atlantic. Two waves developed into Debby and Helene, two waves are unambiguously nondeveloping, and three others are questionable in their role in the development of Ernesto, Florence, and Gordon. NCEP GDAS (Global Data Assimilation System) analyses, which are used to track both vorticity maxima and the mid-level wave trough associated with the waves, supplement and are compared with observational data to determine how well the GDAS analysis resolves the easterly wave wind structure. Results show an important distinction between tracking the large-scale easterly wave trough and vorticity centers within the wave. For NAMMA easterly waves, the vorticity maxima lag the wave trough over the ocean. Observations also show that wave-to-wave, the synoptic-scale circulations and troughs associated with easterly waves vary from well-defined to diffuse, and that the coherence may be impacted by subsynoptic-scale processes such as convection (which is difficult to sample). Often, multiple vorticity maxima are observed with a single easterly wave and the co-location of vorticity maxima with convection may be relevant for tropical cyclogenesis. For NAMMA, easterly waves with well-defined synoptic-scale circulations and troughs are well resolved by the analysis, have limited convection and are not observed to develop. On the other hand, easterly waves with weak synoptic-scale features that have widespread (and in the developing cases, intense) convection are not well handled by the analysis, but are observed to develop. Finally, a comparison of a high resolution WRF simulation of one developing case, Tropical Storm Debby, with aircraft data shows that the simulation lacks a tight, warm core circulation similar to that observed. As with the GDAS analysis, reasons behind the disagreement may include the location of latent heating, error in the initial analysis, the parameterization schemes, or the model resolution

Adaptability and Resilience of Academic Radiation Oncology Personnel and Procedures during COVID-19 Pandemic

Background: A comprehensive response to the unprecedented SARS-CoV-2 (COVID-19) challenges for public health and its impact on radiation oncology patients and personnel for resilience and adaptability is presented. Methods: The general recommendations included working remotely when feasible, implementation of screening/safety and personal protective equipment (PPE) guidelines, social distancing, regular cleaning of treatment environment, and testing for high-risk patients/procedures. All teaching conferences, tumor boards, and weekly chart rounds were conducted using a virtual platform. Additionally, specific recommendations were given to each section to ensure proper patient treatments. The impact of these measures, especially adaptability and resilience, were evaluated through specific questionnaire surveys. Results: These comprehensive COVID-19-related measures resulted in most staff expressing a consistent level of satisfaction in regard to personal safety, maintaining a safe work environment, continuing quality patient care, and continuing educational activities during the pandemic. There was a significant reduction in patient treatments and on-site patient visits with an appreciable increase in the number of telemedicine e-visits. Conclusions: Survey results demonstrated substantial adaptability and resilience, including in the rapid recovery of departmental activities during the reactivation phase. In the event of a future public health emergency, the measures implemented may be adopted with good outcomes by radiation oncology departments across the globe

Potential Exposure of Pollinators to Neonicotinoid Insecticides from the Use of Insecticide Seed Treatments in the Mid-Southern United States

Research was done during 2012 to evaluate the potential exposure of pollinators to neonicotinoid insecticides used as seed treatments on corn, cotton, and soybean. Samples were collected from small plot evaluations of seed treatments and from commercial fields in agricultural production areas in Arkansas, Mississippi, and Tennessee. In total, 560 samples were analyzed for concentrations of clothianidin, imidacloprid, thiamethoxam, and their metabolites. These included pollen from corn and cotton, nectar from cotton, flowers from soybean, honey bees, <i>Apis mellifera</i> L., and pollen carried by foragers returning to hives, preplanting and in-season soil samples, and wild flowers adjacent to recently planted fields. Neonicotinoid insecticides were detected at a level of 1 ng/g or above in 23% of wild flower samples around recently planted fields, with an average detection level of about 10 ng/g. We detected neonicotinoid insecticides in the soil of production fields prior to planting at an average concentration of about 10 ng/g, and over 80% of the samples having some insecticide present. Only 5% of foraging honey bees tested positive for the presence of neonicotinoid insecticides, and there was only one trace detection (< 1 ng/g) in pollen being carried by those bees. Soybean flowers, cotton pollen, and cotton nectar contained little or no neonicotinoids resulting from insecticide seed treatments. Average levels of neonicotinoid insecticides in corn pollen ranged from less than 1 to 6 ng/g. The highest neonicotinoid concentrations were found in soil collected during early flowering from insecticide seed treatment trials. However, these levels were generally not well correlated with neonicotinoid concentrations in flowers, pollen, or nectar. Concentrations in flowering structures were well below defined levels of concern thought to cause acute mortality in honey bees. The potential implications of our findings are discussed

The Joint Aeolus Tropical Atlantic Campaign 2021/2022 Overview- Atmospheric Science and Satellite Validation in the Tropics

International audienceESA's Aeolus satellite observations are expected to have the biggest impact for the improvement of numerical weather prediction in the Tropics. An important case relating to the predictability of tropical weather systems is the outflow of Saharan dust, its interaction with cloud microphysics and impact on the development of tropical storms over the Atlantic Ocean.The Joint Aeolus Tropical Atlantic Campaign (JATAC) deployed on Cabo Verde (2021/2022) and the US Virgin Islands (2021) supported the validation and preparation of the ESA missions Aeolus, EarthCARE and WIVERN, and addressed science objectives regarding the Saharan Aerosol layer, African Easterly Waves and Jet, Tropical Easterly Jet, and the Intertropical Convergence Zone, as well as their relation to the formation of convective systems, and the long-range transport of dust and its impact on air quality.JATAC started in July 2021 with the deployment of ground-based instruments in the frame of the ASKOS project at the Ocean Science Center Mindelo, including the eVe and PollyXT lidars, and a W-band Doppler cloud radar. By mid-August, the CPEX-AW campaign started operations from the US Virgin Islands with NASA's DC-8 flying laboratory in the Western Tropical Atlantic and Caribbean carrying the Doppler Aerosol Wind Lidar (DAWN), Airborne Precipitation and Cloud Radar (APR-3), Water Vapor DIAL and HSRL (HALO), microwave sounder (HAMSR) and dropsondes. In September the DLR Falcon-20 aircraft, carrying the ALADIN Airborne Demonstrator (A2D) and the 2-µm Doppler wind lidar, and the Safire Falcon-20, carrying the high-spectral-resolution Doppler lidar (LNG), the RASTA Doppler cloud radar, in-situ cloud and aerosol instruments, and dropsondes, were deployed to Sal in the frame of the AVATAR-T and CADDIWA projects. The Aerovizija Advantic WT-10 light aircraft with optical particle spectrometers, filter-photometers and nephelometers for in-situ aerosol characterisation was operating in close coordination with the ground-based observations in the CAVA-AW project.The activities continued in June 2022 when the ASKOS ground based observations were enhanced with UAV airborne in-situ aerosol measurements deployed by the Cyprus Institute, solar radiation measurements supported by PMOD/WRC, dust particle orientation measurements (WALL-E lidar), and radiosonde releases equipped with electric field-mills. NASA deployed the DC-8 aircraft all September to Sal with the 2021 payload in the framework of the CPEX-CV activity, including regular radiosonde launches. As in 2021, the Aerovizija aircraft took part with in-situ aerosol measurements during two weeks in September. JATAC was supported by dedicated numerical weather and dust simulations supporting forecasting efforts and addressing open science questions.Around 60 scientific flights of four aircraft, with an additional 25 UAV flights, were performed during JATAC. 23 Aeolus orbits were underflown, many of them with simultaneous observations of multiple aircraft collocated with ground-based observations. In addition, the science objectives were fully covered through the large number of flights, ground based cloud and aerosol observations, regular radiosondes and dropsondes.Overall, JATAC activities have resulted in a high-quality and comprehensive dataset supporting a wide range of tropical atmospheric research, the validation of Aeolus and other satellites, and have provided key reference data for the development future Earth Observation missions

Recent advancements in aircraft and in situ observations of tropical cyclones

Observations of tropical cyclones (TC) from aircraft and in situ platforms provide critical and unique information for analyzing and forecasting TC intensity, structure, track, and their associated hazards. This report, prepared for the tenth International Workshop on Tropical Cyclones (IWTC-10), discusses the data collected around the world in TCs over the past four years since the IWTC-9, improvements to observing techniques, new instruments designed to achieve sustained and targeted atmospheric and oceanic observations, and select research results related to these observations.In the Atlantic and Eastern and Central Pacific basins, changes to operational aircraft reconnaissance are discussed along with several of the research field campaigns that have taken place recently. The changes in the use and impact of these aircraft observations in numerical weather prediction models are also provided along with updates on some of the experimental aircraft instrumentation. Highlights from three field campaigns in the Western Pacific basin are also discussed. Examples of in-situ data collected within recent TCs such as Hurricane Ian (2022), also demonstrate that new, emerging technologies and observation strategies reviewed in this report, definitely have the potential to further improve ocean-atmosphere coupled intensity forecasts

In the Driver's Seat: Rico and Education

The Rain in Cumulus over the Ocean (RICO) field campaign carried out a wide array of educational activities, including a major first in a field project—a complete mission, including research flights, planned and executed entirely by students. This article describes the educational opportunities provided to the 24 graduate and 9 undergraduate students who participated in RICO