Loren D. White

Simulation of Atmospheric Dispersion of Elevated Releases from Point Sources in Mississippi Gulf Coast with Different Meteorological Data

Atmospheric dispersion calculations are made using the HYSPLIT Particle Dispersion Model for studying the transport and dispersion of air-borne releases from point elevated sources in the Mississippi Gulf coastal region. Simulations are performed separately with three meteorological data sets having different spatial and temporal resolution for a typical summer period in 1–3 June 2006 representing a weak synoptic condition. The first two data are the NCEP global and regional analyses (FNL, EDAS) while the third is a meso-scale simulation generated using the Weather Research and Forecasting model with nested domains at a fine resolution of 4 km. The meso-scale model results show significant temporal and spatial variations in the meteorological fields as a result of the combined influences of the land-sea breeze circulation, the large scale flow field and diurnal alteration in the mixing depth across the coast. The model predicted SO2 concentrations showed that the trajectory and the concentration distribution varied in the three cases of input data. While calculations with FNL data show an overall higher correlation, there is a significant positive bias during daytime and negative bias during night time. Calculations with EDAS fields are significantly below the observations during both daytime and night time though plume behavior follows the coastal circulation. The diurnal plume behavior and its distribution are better simulated using the mesoscale WRF meteorological fields in the coastal environment suggesting its suitability for pollution dispersion impact assessment in the local scale. Results of different cases of simulation, comparison with observations, correlation and bias in each case are presented.

Numerical simulation for a wind dust event in the US/Mexico border region

Soil-derived dust represents one of the major components of the natural atmospheric aerosols. Arid and semiarid areas with unpaved and non-vegetated land cover are particularly vulnerable to windblown dust, which results in high particulate matter pollution. To understand, predict, and mitigate the impact of dust aerosol on air quality and climate, it is necessary to parameterize the emission rate of dust particles from the wind erosion processes accurately. However, windblown dust emission is poorly represented in existing air quality models. In this paper, a windblown dust emission model has been developed based on a parameterization of threshold wind friction velocity depending on the roughness of surface, vegetation type, soil type, soil moisture content, and on the size distribution of aerosols. The proposed dust model incorporates into a region air quality modeling system to simulate a North American dust storm episode occurring near the border of southwestern USA and northwestern region of Mexico on 23 February 2007. It is shown that the implementation of a windblown dust model in an air quality model can significantly improve the model capability for capturing the dust episode. The simulation of the model is in good agreement with the evolution of dust distribution. The modeled dust spatial patterns matched dust cloud patterns appearing on satellite images. Implementation of the windblown dust model successfully captured the time of peak particulate matter (PM) concentrations for both PM10 and PM2.5, as well as the peak value of the PM2.5 concentration. The modeled results clearly demonstrate an improved ability to predict PM events by applying the windblown dust emission scheme.

Thirty Years of Meteorological Education at a Historically Black University

ABSTRACT Since 1975, the Jackson State University Meteorology Program (JSUMP) has played a unique role in the preparation of minorities for careers in the atmospheric sciences. Through external partnerships, incorporation of undergraduate research, summer internships, and involvement in activities of the professional societies, the JSUMP has graduated around 55 atmospheric scientists from underrepresented minorities between 1978 and 2008. In recent years, about half of the graduates have continued on to graduate school. These contributions are important to the National Oceanic and Atmospheric Administrations (NOAA) goal to develop a more diverse workforce, in particular for the National Weather Service. The JSUMP has also become active in outreach activities to K–12 schools and the general public through workshops, camps, and Web sites.