I am an atmospheric chemist with broad interests in air quality, climate, and atmosphere-biosphere interactions. My research group makes measurements at the Earth’s surface and from onboard aircraft in diverse locations, including polluted cities, agricultural areas, and within forest canopies. Our focus is on the role of reactive nitrogen in chemical oxidation mechanisms and emissions of the greenhouse gas nitrous oxide. We utilize spatial and temporal variability in our datasets to derive mechanistic insight into processes taking place in urban and human-influenced environments.
As a meteorologist interested in understanding the chemistry of the non-urban troposphere, and how it may be changing as a result of anthropogenic impact, I use meteorological data (including satellite observations) and models to discern dynamical processes that influence or control atmospheric composition. In several instances my students and I have also gone in the field, collecting data directly (e.g., from the balloon launches of ozonesondes over Charlottesville, Virginia; Sable Island, Nova Scotia; Boulder, Colorado; and Pellston Michigan; to the deployment of an NCAR boundary layer
Pollutant emissions are significantly altering the chemical composition of the atmosphere and its impacts on other earth systems. My research focuses on resolving fundamental chemical and physical processes in the troposphere and differentiating anthropogenic and natural influences.
The shorezone of sedimentary coasts, in climatological time, is fluid-like in its attributes and driven by atmospheric and oceanic motions. Coastal climatology, one of my areas of specialization, focuses on spatial and temporal variations of these three fluids, their interactions and effects on coastal ecosystems. Recent focus has included the Virginia Coast Reserve LTER research site with special attention to the long term changes in climate and vegetation at that site and on the modeling of the dynamics of the barrier island landscape.
My research group focuses on atmospheric dynamics and their role in variability and long-term change in the climate system. In our research, we explore key questions about the dynamics of the climate system through statistical analyses of intraseasonal, interannual, and decadal variability in observational data sets and climate model output.
Convective storms, sometimes reaching into the stratosphere, play a major role in maintaining the heat balance of the atmosphere and in governing the vertical distribution of critical trace gases and aerosols. Work involving the coupling of the deeper atmosphere to the surface and boundary layers is being conducted over the tropical Atlantic and Pacific. Other studies, which capitalize upon knowledge of convective storms and the boundary layer, include global and regional rainfall, gaps in the rainforest and low-frequency sound transmission.
Landscape heterogeneities can have pronounced effects on atmospheric boundary layer processes. Examples include a modification of the boundary layer growth and the generation of mesoscale circulations. My research focuses primarily on the investigation of these processes in hilly and mountainous terrain using a combination of field studies, data analysis, and numerical modeling techniques. I seek to apply my expertise to problems in a multi-disciplinary context such as found at the interface with ecology, atmospheric chemistry, and hydrology.
The climate at any one location is determined by the temporal progression of synoptic-scale weather events. My research focuses on the temporal and spatial variability of these synoptic-scale systems and their impact upon various environmental parameters, such as air-quality and human health. Current research involves examining how weather and climate influence severe cases of respiratory distress, which can be related to both pollutants and aeroallergens as well as short-term changes in weather conditions.