Department of Atmospheric Sciences and Chemistry

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Now showing 1 - 5 of 61
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    (2023-08) Connelly, Brittany
    ABSTRACT DOWNWARD TRENDS OF SULFUR DIOXIDE (SO2 ) EMISSIONS IN THE NORTHEAST DUE TO THE CLEAN AIR ACT: A CLIMATOLOGY OF THE REDUCTION OF ACID RAIN by Brittany C. Connelly M.S. in Applied Meteorology, Plymouth State University, August 2023 Anthropogenic emissions of sulfur dioxide (SO2 ) are primarily caused the by burning of sulfur containing fossil fuels at power plants for heat and power generation. Emitted SO2 reacts with oxygen (O2 ) in the atmosphere to form the secondary pollutant sulfate (SO4 ). Acid rain formation is the result of a change in atmospheric chemistry when SO4 combines with water vapor (H2 O) in the air to form sulfuric acid (H2 SO4 ). The Clean Air Act (CAA) was federally implemented by the United States Environmental Protection Agency (EPA) to regulate hazardous air emissions which initiated the creation of National Ambient Air Quality Standards (NAAQS) to protect public health and the environment. Individual states are required to work with the Environmental Protection Agency (EPA) to create state implementation plans (SIPs) in order to comply with NAAQS which, help regulate and decrease air pollution. This study contains a meteorological background of the transport of SO2 emissions from power plants from the Midwest to the Northeast. There are three main components to this study: a 10-year analysis of the trends in hourly SO2 concentrations in the Northeast compared to wind direction, a case study comparing SO4 concentrations to two days that have different meteorological conditions that impact winds, and a 35-year climatological analysis in acid rain trends throughout the Northeast. Environmental and human health impacts of SO2 as a primary air pollutant, in addition to the secondary air pollutants that result from SO2 emissions such as SO4 and acid rain, are discussed, indicating the importance in SO2 emission regulations of the CAA. Annual hourly SO2 concentrations at two Interagency Monitoring of Protected Visual Environments (IMPROVE) sites at Lawrenceville, PA and Londonderry, NH show a gradual decrease from 2012 to 2021. Higher SO2 concentrations were measured when winds were from the south or southwest with exception of Lawrenceville, PA site that had the greatest SO2 concentrations from the northwest which is influenced by surrounding topography. The case study for this study analyzes daily SO4 concentrations from different wind directions on two days in the summer of 2022 at the same two IMPROVE sites that were analyzed for SO2 concentrations. When winds were from the north on 1 July 2022, the measured SO4 concentrations were 1.838 μg/m 3 at the Lawrenceville, PA site and 1.508 μg/m 3 at the Londonderry, NH site. When winds were from the southwest on 12 August 2022, the measured SO4 concentrations were 0.188 μg/m 3 at the Lawrenceville, PA site and 0.315 μg/m 3 at the Londonderry, NH site. Lastly, the acid rain climatological analysis of 19 National Trends Network (NTN) sites throughout the Northeast show an increase in precipitation pH and a decrease in SO4 concentrations between 1985 and 2020 at all 19 sites.
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    Microbursts and Null Events Near Cape Canaveral, FL
    (2023-05) White, Danielle
    Abstract MASTER OF SCIENCE IN APPLIED METEOROLOGY By Danielle White Plymouth State University, May, 2023 Microbursts are thunderstorm downdrafts that produce localized damaging wind, no larger than 4 km in diameter (Bringi et al. 1996). These storms, which typically contain hail in the early stages of development may not produce rain and can occur in any geographic region (Amiot et al. 2019). In Florida, wet microbursts commonly pose a major risk to operations at Cape Canaveral Air Force Base. To improve forecasting microbursts, six variables were derived from sounding data provided by the University of Wyoming, valid no more than 4 hours before thunderstorm formation, and including CAPE, KI, TT, ∆𝜃! , mid-level relative humidity, and sub-cloud humidity. Peak wind speeds provided by Kennedy Space Center were recorded where the reflectivity is at least 45 dBZ occurring above the freezing level. Comparisons of null and microburst events with this data were used in analysis to determine how well each of the six variables do in microburst detection. The relative humidity variables proved to be the best indicators. Ideal humidity values may vary based on location but should be low enough for hail to melt and evaporate to induce negative buoyancy, but not so low that the thunderstorm begins to lose moisture and structure. A similar explanation can be applied to the ∆𝜃! , which was also found to be helpful in forecasting microbursts. New thresholds for each variable were determined to maximize the performance of forecasting guidance.
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    A Statistical Analysis of Radar and MRMS QPE in the Northern Plains and Mid-Atlantic
    (2023-05) Steen, Matthew
    ABSTRACT A Statistical Analysis of Radar and MRMS QPE in the Northern Plains and Mid-Atlantic by Matthew C. Steen Plymouth State University, May, 2023 Over the last 40 years weather radar has provided an immense amount of data across the United States. Radar precipitation estimates provide a much higher spatial and temporal density of observations than ground-based measurements. In recent years, dual- polarization capabilities introduced to NEXRAD WSR-88Ds provided improvements to precipitation estimations allowing for more accurate forecasts and warnings. Also, the Multi-Radar/Multi-Sensor System (MRMS) has developed a set of hydrometeorological based algorithms which take in data from radars, satellites, surface and upper air observations, models, and lightning detection systems to create a wide array of products that assist in decision-making and provide improved weather forecasting tools. The MRMS and Dual-pol radar Quantitative Precipitation Estimations (QPEs) are being used more by analysts in place of the previous radar precipitation estimation algorithm, the Precipitation Processing System (PPS). The goal of this research is to compare the Sioux Falls, SD (KFSD) and Dover, DE (KDOX) WSR-88Ds dual-polarized radar rainfall estimates and MRMS radar-only rainfall product estimates to rain gauge measurements for precipitation events in these regions. KFSD was selected because there have been few radar QPE studies in the Northern Plains. KDOX was selected for similar reasons (few studies in the mid-Atlantic) along with providing a perspective from a different climatic xi regime within the United States. Hourly rain-gauge precipitation estimates within 100 km of KFSD for events with at least one hour of observed rainfall greater than or equal to five millimeters were analyzed. These observed values were compared with high and low resolution dual-polarization QPE and MRMS radar-only estimates. Results demonstrate that the MRMS radar-only product produced better precipitation estimates than both high and low resolution dual-polarized estimates at both KFSD and KDOX. The mean absolute error (MAE) for MRMS was lower than both radar products at KFSD while the high-resolution radar product produced a similar MAE at KDOX. The differences in MAE between the low resolution dual-pol QPE and the MRMS and the high resolution dual-pol QPEs were determined to be statistically significant at both stations. The average bias of the MRMS was lower than both radar products for both radars, with a larger difference between the MRMS and low resolution dual-pol QPE than high resolution estimates. Like MAE, the difference between the low resolution dual-pol QPE and the MRMS and the high resolution dual-pol QPEs were determined to be statistically significant at both stations. Based on the results of this study, forecasters may be more inclined to favor the estimations of MRMS-based products for the forecasting of rainfall and issuing of rainfall related watches and warnings.
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    The Disparity of In-Situ Weather Stations on Indigenous Nations Versus State Lands in the United States
    (2021-07-28) Adams, Sophia; Avilés, Lourdes; Miller, Samuel; Lemcke-Stampone, Mary
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    Analysis of Extratropical Transition or Dissipation of TCS that made Landfall in the Contiguous United States from 2000-2019
    (21-May) Rodríguez, Manuel Iván Ramos; Hoffman, Eric G.; Aviles, Lourdes B.; Villamagna, Amy M.
    Electronic Thesis or Dissertation