A new continuous planar fit method for calculating fluxes in complex, forested terrain

Abstract

The planar fit (PF) method is often recommended for long-term eddy covariance flux measurements because it offers a number of advantages over rotating into streamwise coordinates. For sites over complex, forested terrain a single PF may not account for complex variations in slope and canopy cover with wind direction. An alternative to the PF method is presented where the tilt angle is fitted as a continuous function of the wind direction. This retains many of the benefits of the PF method, while at the same time better representing local variations in tilt with wind direction.