Long-term atmospheric chemistry measurements for research and satellite validation in the Southeastern US.

Fundamental research on the air-surface exchange of trace gases and particles requires high quality, process level data collected over long time periods. Satellite data validation depends upon well-characterized data collected over the operational lifetime of a mission. The EPA, in collaboration with NASA LaRC and GSFC, DoE, LuftBlick, and Duke University are developing a long-term atmospheric research site, located at Duke Forest in the North Carolina piedmont, to meet data needs now and well into the future. The Duke Forest site will collect continuous measurements of ground level and vertical column trace gases, micrometeorology and atmospheric mixed layer height at two primary research locations, a 14 hectare open cleared field and 45 meter research tower above a mixed hardwood forest. Gas phase measurements include in-situ NO₂, NO_x/NO_y, NH_x, O₃, HCHO, NH₃, CO₂ and N₂O with its isotopologues; eddy covariance flux measurements of O₃, NH₃, NO_y, H₂O and CO₂; and vertical column densities of NO₂ and HCHO by Pandora 2S UV/Visible spectrometer. Particle phase measurements of NH₃, NH₄ and SO₄ will be acquired along with AERONET derived AOD products. These datasets will be used to understand the role of biogenic emissions in ozone formation and transport, model reactive nitrogen budgets in a forested landscape, estimate fluxes of climate forcing trace gases and support TropOMI and TEMPO satellite data product validation. Duke Forest is also an EPA Clear Air Status and Trends Network (CASTNET) and National Atmospheric Deposition Program Ammonia Monitoring Network (AMoN) site. Data collected will made available through the NASA data archive and other public outlets for EPA monitoring data.