Sampling errors in the vertical fluxes of potential temperature and moisture measured by aircraft during FIFE

The First International Satellite Land Surface Climatology Project (ISLSCP) Field Experiment (FIFE) was carried out over a 15 × 15 km area in central Kansas Sellers et al ., this issue. The site size was constrained by land use characteristics, topography, and, importantly, the ability to field a reasonable network of surface observations of plant physiology, soil moisture, and radiative characteristics as well as surface observations of meteorological observations, including vertical fluxes of sensible heat and moisture. As described by Kelly this issue, aircraft flying within the atmospheric boundary layer over the FIFE site played an important role: they provided direct measurements of the vertical fluxes of sensible heat and moisture above the FIFE site. Potential temperature flux and sensible heat flux differ by the constant ρ d c p , where ρ d is the dry air density (which is nearly constant in the atmospheric boundary layer) and c p is the specific heat of dry air at constant pressure.