The effect of static pressure-wind covariance on vertical carbon dioxide exchange at a windy subalpine forest site

•The NEE pressure term is small over the diel cycle (relative to other WPL terms).•The pressure term can be significant for annual NEE, especially at windy locations.•At GLEES, the annual cumulative pressure term accounted for about 20% of total NEE.•Our study shows what makes the measurement of w′p′¯ so challenging and unique.•We present in-situ experiments on the effect of tilting the quad-disk.