Evaluating the calculated dry deposition velocities of reactive nitrogen oxides and ozone from two community models over a temperate deciduous forest ) is very sensitive to the minimum canopy stomatal resistance (R i ) which is specified for each seasonal category assigned in WDDM. Treating Sep-Oct as autumn in WDDM for this deciduous forest site caused a large underprediction of V d (O 3 ) due to the leafless assumption in 'autumn' seasonal category for which an infinite R i was assigned. Reducing R i to a value of 70 s m À1 , the same as the default value for the summer season category, the modeled and measured V d (O 3 ) agreed reasonably well. HNO 3 was found to dominate the NO y flux during the measurement period; thus the modeled V d (NO y ) was mainly controlled by the aerodynamic and quasi-laminar sublayer resistances (R a and R b ), both being sensitive to the surface roughness length (z 0 ). Using an appropriate value for z 0 (10% of canopy height), WDDM and Noah-GEM agreed well with the observed daytime V d (NO y ). The differences in V d (HNO 3 ) between WDDM and Noah-GEM were small due to the small differences in the calculated R a and R b between the two models; however, the differences in R c of NO 2 and PAN between the two models reached a factor of 1.1e1.5, which in turn caused a factor of 1.1e1.3 differences for V d . Combining the measured concentrations and modeled V d , NO x , PAN and HNO 3 accounted for 19%, 4%, and 70% of the measured NO y fluxes, respectively.