Column-Averaged Atmospheric Carbon and Water at Harvard Forest since 2018

Ground-based total-atmospheric column measurements of CO2, CH4, CO, and H2O began at Harvard Forest in May 2018 using a solar-viewing Fourier Transform Spectrometer (Bruker EM27/Sun). Observations are made from a platform near the Fisher Meteorological Tower throughout the year on sunny days. Total column observations are sensitive to regional carbon fluxes, and are less impacted by changes in the boundary layer height than tower based in-situ observations. The Harvard Forest observations are complemented by an identical instrument operated on the Harvard campus in Cambridge MA. The two sensors are used to support studies of urban emissions, regional transport, and forest-atmosphere exchange. In addition, the total-column measurements provide key validation data for satellite measurements of greenhouse gases.