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The purpose of this study was to investigate students' conceptions of the greenhouse effect, global warming, and climate change. The study was descriptive in nature and reflected a cross-age design involving the collection of qualitative data from 51 secondary students from three different schools in the Midwest, USA. These data were analyzed for content in an inductive manner to identify student's conceptions. The categories that emerged from the students' responses reflected different degrees of sophistication of students' conceptions about the greenhouse effect, global warming, and climate change. Based on these findings we make curricular recommendations that build on the students' conceptions, the IPCC Findings, the NRC (1996) science education standards, and NOAA's climate literacy framework.

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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.

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