The BOREAS AFM-04 team used the NRC Twin Otter aircraft in 1994 and 1996 to make measurements in the boundary layer of the fluxes of sensible and latent heat, momentum, ozone, methane, and carbon dioxide, plus supporting meteorological parameters such as temperature, humidity, and wind speed and direction. Aircraft position, heading, and altitude were also recorded, as were several radiometric observations for use in interpretation of the data (greenness index, surface temperature, incoming and reflected radiation). Data were collected at both the NSA and SSA during the three 1994 IFCs and in July and August of 1996.