Since the beginning of my internship at the Smithsonian Environmental Research Center, I have been working on analyzing CO₂-flux and concentration measurements, accumulated during an ongoing 15-year project on salt marsh responses to elevated CO₂. I read some literature concerning topics related to the research conducted here, studied the basics about using simple procedures of the SAS software and generating graphs in Sigmaplot, knowledge which proved to be essential and useful for my project.

Under the supervision of Bert Drake and the guidance and help of Daniel Rasse, I began my project regarding the change of CO₂ concentration at a level 3-m above the ground. The data I used were measurements collected at the research site from 1990 to 2000 between May through September of each year. I have been studying the changes in atmospheric CO₂ concentration and its correlation with meteorological variables such as the photosynthetic flux, the temperature, the precipitation and the wind. My data analyses revealed that the CO₂ concentration steadily increased during the 11-year period as indicated by the average of the 9am-3pm July measurements. This increase paralleled that of the Mauna Loa atmospheric measurements for the same 11-year period. For each year, it turned out that the 9am-3pm averaged values were highest in May and September and lowest in July. Moreover, I found that the daily pattern of the CO₂ concentration displays a sharp drop shortly after dawn and that daytime and nighttime CO₂ concentrations differ a lot.