Remata S. Reddy

Sensitivity modeling study for an ozone occurrence during the 1996 Paso Del Norte Ozone Campaign.

Surface ozone pollution has been a persistent environmental problem in the US and Europe as well as the developing countries. A key prerequisite to find effective alternatives to meeting an ozone air quality standard is to understand the importance of local anthropogenic emissions, the significance of biogenic emissions, and the contribution of long-range transport. In this study, an air quality modeling system that includes chemistry and transport, CMAQ, an emission processing model, SMOKE, and a mesoscale numerical meteorological model, WRF, has been applied to investigate an ozone event occurring during the period of the 1996 Paso del Norte Ozone Campaign. The results show that the modeling system exhibits the capability to simulate this high ozone occurrence by providing a comparable temporal variation of surface ozone concentration at one station and to capture the spatial evolution of the event. Several sensitivity tests were also conducted to identify the contributions to high surface ozone concentration from eight VOC subspecies, biogenic VOCs, anthropogenic VOCs and long-range transportation of ozone and its precursors. It is found that the reductions of ETH, ISOP, PAR, OLE and FORM help to mitigate the surface ozone concentration, and like anthropogenic VOCs, biogenic VOC plays a nonnegligible role in ozone formation. But for this case, long-range transport of ozone and its precursors appears to produce an insignificant contribution.

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.

Multiscale comparison of air quality modeling for an ozone occurrence during the 1996 Paso Del Norte Ozone Campaign

An air quality modeling has been applied to investigate an ozone event occurring during the period of 1996 Paso del Norte Ozone Campaign. An examination of model sensitivity to horizontal grid resolutions has been performed. The modeling results show that grid resolution evidently influences the simulations of ozone formation, dispersion, transportation and structural distribution. The 36-, 12-, 4- and 1-km models captured the diurnal variation of surface ozone, but with a few hours lag for simulated peak ozone. The coarser the spatial resolution of the model, the more the peak ozone lag occurs. All models underpredicted the peak ozone concentration where the 1-km model produced the best while the 36km model yielded the worst. This study suggests that the problems of maximum ozone underprediction and minimum ozone overprediction can be mitigated by increasing the spatial resolution of the model. Compared to fine models, coarse models provided rather simple and smooth structures with many detailed and complex structures being lost. The frequency distribution analysis also revealed that the high ozone event occurring over the complex terrain area such as El Paso, TX can hardly be captured by using coarse spatial resolution models, and the high resolution model (i.e., grid spacing is no greater than 4-km) is necessary.

Simulation and prediction of hurricane Lili during landfall over the central gulf states using MM5 modeling system and satellite data

A mesoscale modeling investigation of tropical cyclone/hurricane forecast over the Gulf of Mexico has been established under the NASA/HBCU Renewable Energy and Technology Project to adopt the numerical weather prediction model for possible use in regions where solar equipment will be used. Accurate and reliable forecasting is crucial in regions that have limited resources where renewable solar energy can be utilized. Devices such as solar cookers and solar Sterling engines can be effectively operated under adequate sunlight in converting solar energy to cook food. The study also involves in understanding the structure and dynamics of land falling tropical cyclones over the Gulf coast under the project — Diversity in Atmospheric Science through Research Application and Partnership (IDAS-RAP) with NWS/NOAA. Cloud cover, temperature, radiation, and precipitation are major factors that help the operation of such devices; therefore weather conditions must be predicted fairly well in advance so that appropriate measures may be taken to protect solar assets. A case study on Hurricane Lili 2002 (September 21-October 4) has been modeled to show changes in weather conditions that could affect solar-energy utilization. The PSU/NCAR Mesoscale Model (MM5) is used to simulate the storms formation and development, and predict its track and intensity change. The simulation was for a period of two days during October 3 and 4 when hurricane Lili made landfall over the coastal areas of Louisiana and Mississippi. Model configuration includes two nested domains of 85×85 and 91×91 dimensions respectively. Inner domain is two-way. The outer domain of grid size 27 km is positioned over the Gulf of Mexico region, and the nested domain of grid size 9 km closer to the coast of LA-MS. Objective analysis is done using NCEP ADP Global Surface Observations. Model predicted compared with aircraft observations taken by the National Hurricane Center and noted reasonably good agreement. The present study will aid in determining weather conditions well in advance so that early warnings can be issued and damage to life and property can be averted.

The atmospheric processes associated with the tornadic super-outbreak of April 25 th through 28 th 2011 in relation to global change

A large and violent super-tornado outbreak occurred from April 25th - 28th, 2011, becoming the deadliest 24-hour outbreak in U.S history. According NOAA and the SPC, there were approximately 190 tornadoes reported with 320 deaths within the southern, mid-western and northeastern U.S. In the current study, Arctic sea ice loss affecting the North Atlantic Oscillation, a negative ENSO episode, Gulf of Mexico Sea Surface Temperatures (SSTs) and an unusual shift of dry-line associated with parent mid-latitude cyclone (MCL) are potentially influenced by global change in association with the outbreak and studied using NCEP/NCAR reanalysis, GFS modeling, NCEP/CPC CAMS & NOAA/ESRL/PSD NOAA/AOML/TCHP analysis, and stability parameters obtained from remote sensing. Larger implications state the Arctic sea ice lost reversed upper-level wind distribution and affected major wind systems such as the jet stream. Reduced albedo in the arctic increased solar insolation and shifted the temperature differential between latitudes, potentially perturbing Earths feedback system.

Mesoscale modeling investigation of air-sea interactions over the Gulf of Mexico for a case study of Hurricane Gordon

Under the NASA/FAR Program, a study has been established to investigate air-sea interactions associated with the formation and development of Hurricane Gordon in the Gulf of Mexico. Hurricane Gordon was a Category 1 storm, which formed in the Gulf of Mexico on September 17th, 2000. We are using the Penn State/NCAR MM5 (version 3) modeling system for diagnostic studies of surface fluxes (sensible heat, latent heat, and momentum) over the Gulf of Mexico relevant to the air-sea interactions in the vicinity of this intense hurricane. The MM5 configuration features two nested domains over the Gulf of Mexico; with horizontal grid spacing of 90 km and 30 km. Nesting between the grids is two ways. Physics options selected include: non-hydrostatic; Grell cumulus parameterization on 90 km grid; explicit microphysics (Reisner) on 30 km grid; modified Mellor-Yamada boundary layer parameterization; and a cloud-resolving radiation scheme. Gridded analysis and rawinsonde data from NCAR were used to construct initial and boundary condition files. The model results will be discussed, along with relation to other theoretical and modeling studies of air-sea interactions in hurricane environments. Potential links between the model surface fluxes and precipitation at landfall will be considered.

A study of the air-sea interactions and associated Hurricane Gordon in the Gulf of Mexico

Under the NASA/FAR Program, a study has been established to investigate air-sea interactions associated with the formation and development of Hurricane Gordon in the Gulf of Mexico. Hurricane Gordon first began as a weak disturbance off the eastern shore of the Yucatan Peninsula on September 10th, 2000. The area of disturbed weather moved onshore then offshore again on the northern coast of the Yucatan Peninsula. The convection developed a surface low and was named Tropical depression number 11. It then strengthened, becoming a named tropical storm, Gordon, on September 15th and then a minimal hurricane on September 16th as it neared the Florida Panhandle. It weakened to tropical storm status late on September 17th, a few hours before it made landfall. NOAA buoy data from the National Data Buoy Center are used in this study. Remote Sensing GOES and AVHRR satellite data from NOAA are used as well. These data were used in the calculation of heat, momentum, and moisture fluxes. The study indicated that (a) average sea-surface temperatures over the Gulf of Mexico were about 29/spl deg/C, and (b) the air-sea inter phase was a maximum 3-4 days before the storm developed. We further investigate to development of predictive models including (i) a regression model, and (ii) a Hurricane Predictive Index, for forecasting the formation and development of Hurricane Gordon that occurred during September 11-20, 2000.