Although tropospheric NO, NO , and O rapidly interconvert in a fast photochemical cycle, 23 the processes governing their removal rates, interactions with ecosystems, and human interest in their mitigation are distinctly different. Thus a detailed understanding of their behavior at the atmosphere-biosphere interface is crucial. The reactivity of this family of gases has often confounded measurements in the past, and the question of biospheric emission and uptake of NO remains open(Lerdauetal.,2000).

In order to address these issues, we present concurrent eddy covariance fluxes of...

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Nitric acid (HNO3) and total reactive nitrogen (NOy) were measured at the Harvard Forest Long Term Ecological Research site in central Massachusetts along with micrometeorological and supporting data during the summer and fall of 2000. The concentration of HNO3 was measured using a tunable diode laser absorption spectrometer (TDLAS) installed on a tower above the forest canopy. The inlet was designed to keep the residence time short, to minimize wall effects, and to exclude aerosols from the sample flow. The TDLAS specifically and quantitatively measured gas-phase HNO3, eliminating... Read more about Deposition of HNO3 to a Northeastern U.S. Forest and its Contribution to NOy Flux

Barford et al.

We report concentrations of atmospheric NO_x, nitric acid (HNO₃), peroxyacetyl nitrate (PAN), and NO_y; eddy covariance fluxes of NO_x and NO_y; inferred fluxes of HNO₃ at the mixed deciduous Harvard Forest field site, June–November 2000. A novel Tunable Diode Laser Absorption Spectrometer (TDLAS) produced sensitive, hourly HNO₃ concentration data, which were used to evaluate systematic error in the Dry Deposition Inferential Method (DDIM), often employed to estimate... Read more about Atmospheric Reactive Nitrogen Partitioning and Fluxes at Harvard Forest