My research interest is increasing the understanding of surface-atmosphere exchange of trace gases (water and carbon dioxide). I am currently focused on the carbon cycle in a wetland and how it is affected by local processes. The study targets a salt marsh ecosystem on the Virginia Coast Reserve, which is home to various fishery industries with important ecosystem concerns. Using continuous measurements on a 7 m tower, properties of the surface layer (e.g., air temperature, soil temperature, photosynthetically active radiation) above the marsh are resolved to determine their influence on the vertical carbon exchange. The field investigations will show how tidal influence and environmental drivers affect the carbon dioxide exchange, calculated from the eddy-covariance methodology. Salt marshes are some of the most susceptible biomes to climate change, and a greater understanding of their carbon cycle will help policy makers and officials to mitigate climate change. While this dissertation addresses the local influence of environment and climate on carbon exchange, its results carry an impact on the global scale.
Meteorology and Atmospheric Science
Adviser: Dr. Jose D. Fuentes; Committee: Dr. Ray G. Najjar, Dr. Ken J. Davis, Dr. Rob P. Brooks
August 2013 - Present
Mechanical and Aersospace Engineering
August 2001 - June 2003
Mechanical and Aerospace Engineering
August 1995 - June 2001
August 1991 - June 1995
The Photochemical Halogen and Ozone eXchange: a Meterological Experiment on Layered Turbulence (PHOX:MELT) experiment measured halogen fluxes and vertical mixing to constrain a one-dimensional mixing model. Air turbulence measurements from a 12-m tower were used to investigate the impact of the surface fluxes, and how they may change as climate change alters the Arctic surface. The resulting field data and observations were used to develop and test an explicit 1D model, which can be used to address the project questions, and incorporated into larger-scale 3D and Earth system models.
Measurements of the air turbulence and air chemistry within and above a dense rain forest were made from a 50-m tower. The project investigated the influences of atmospheric turbulence on the transport and distribution of the hydrocarbons emitted from the forest to determine i) chemical processing of hydrocarbons from reactions, ii) study the chemical conversions associated with cloud condensation nuclei yields during the year.
Measurements of the turbulent fluxes, wind profile, and bulk properties were made from a twin otter operated by the Naval Postgraduate School's (NPS) Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) to characterize the marine atmospheric boundary layer (MABL). These observations helped to understand and parameterize the physics over a range of air-sea interactions through wind speeds, sea state and cloud coverage.
Observations were made of the vertical structure of the MABL from a Lockheed Martin WP-3D airplane managed by the National Oceanic and Atmospheric Adminstaration (NOAA) Aircraft Operations Center. There is substantial evidence showing the global importance of the Madden Julian Oscillation (MJO) and its effect on weather and climate. The measurements of turbulent fluxes, wind profiles, and bulk properties of the MABL enabled the study the MJO with the goal to improve its predictability.
This Office of Naval Research (ONR) Departmental Research Initiative concentrated on the wind forcing and response to the surface wave field through observations made onboard the R/P Floating Instrument Laboratory Platform (FLIP). The field study combined measurements of the wind profile in and near waves, through the surface layer, and into the bulk of the marine boundary layer to determine the phase-resolved surface wave field.
The Variability of the American Monsoon Systems (VAMOS) project focused on to the interplay between the ocean-cloud-atmosphere-land system to improve the understanding of the American monsoon systems in the context of the impact from anthropogenic climate change. A twin otter operated by the Naval Postgraduate School's (NPS) Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) was equipped with a comprehensive suite of instruments to collect data sets to address two broad themes: 1) aerosol-cloud-precipitation interaction in the MABL; 2) coupled ocean-atmosphere-land processes.
Clockwise from left: LIDAR image in Virginia showing marsh elevation. Top right: shows the 7-m tower in the summer of 2016. Btm left: Flux footprint during the summer months showing the distance where the peak flux contribution is from. Btm right: Conceptual figure showing conditions that emphasise a reduction in NEE (namely during higher tides and direct light).
A clear sky day in August reveals the amount of carbon dioxide exchange reduced as a result of inundation on the marsh surface. The difference (∆NEE) between the Michaelis-Menten fit (black - not influenced by inundation) shows the potential NEE (shaded region) that is reduced as a result of inundation.
By applying the daily methodology to all seasons, we show how much net ecosystem exchange is reduced by tidal inundation throughout the year. ∆NEE during the day increased as the inundation increased. The standard error of the sample mean (in symbols) is shaded.
The Virginia Coast Reserve has undergone many changes in the past 15 years. In this 30 year timelapse video, erosion is very discernible on tip of Cobb island. Cobb island is the southern barrier island in this video. Without the protection of the barrier islands blocking the higher energy waves, the marshes will be susceptible to a reduction in size.
Facilitating the ability of governments to implement policies for reduced emissions of greenhouse gases is something I am interested in pursuing. I would love a career providing new knowledge for GHG mitigation policies. I also have an interest in mentoring underrepresented students. I feel it is my responsibility to support others in their academic journey and impart the knowledge I have benefited from.
I highly value being able to disconnect from work and use exercise and cooking as my release. Apart from my investigations, I enjoy most of my time being physically active. During my free time in the winter, I either swim, boulder or play racquetball. In the warmer months, I mix in backpacking, climbing outdoors, and soccer. On the weekends or on days that I have more time, I take pleasure in cooking. I enjoy scouring the web for a new recipe or checking the latest issue of my Bon Appetit magazine.