Atmospheric stability effects on wind fields and scalar mixing within and just above a subalpine forest in sloping terrain

The measurements were sorted by a bulk Richardson number Ri b . For stable conditions, we found vertical scalar differences developed over a "transition" region between 0.05 1), the vertical scalar differences reached a maximum and remained fairly constant with increasing stability.

The relationships q and x c have with Ri b are explained by considering their sources and sinks. For winds, the strong momentum absorption in the upper canopy allows the canopy sublayer to be influenced by pressure gradient forces and terrain effects that lead to complex subcanopy flow patterns. At the dense-canopy sites, soil respiration coupled with wind-sheltering resulted in CO₂ near the ground being 5-7 μmol mol⁻¹ larger than aloft, even with strong above-canopy winds (near-neutral conditions).