Table 4.

Recommendations for Ecosystem-Scale Field Measurement Setups Including Ozone Eddy Covariance Flux and Ozone Concentration Profiles, organized by the scientific question that determines the highest-priority other measurements.

Scientific Question	Other measurements (long term)	Other measurements (short term)
What is the contribution of stomatal uptake to ozone dry deposition?*	water vapor flux, carbon dioxide flux, friction velocity	other independent tracers of stomatal conductance (e.g., carbonyl sulfide flux), canopy skin temperature
What is the contribution of leaf cuticular uptake to ozone dry deposition?	humidity, leaf/canopy wetness, leaf area index, dew point temperature, precipitation, same as * to obtain residual ecosystem-scale nonstomatal conductance	chamber fluxes for ozone around branches including tracers of stomatal conductance to isolate cuticular uptake, composition of cuticles
What is the contribution of soil uptake to ozone dry deposition?	soil moisture and temperature, same as * to obtain residual ecosystem-scale nonstomatal conductance	lower canopy ozone fluxes, fluxes of NO, NO2, and highly reactive BVOC emission from soil, chambers measuring ozone uptake by soil, soil properties (e.g., organic content, clay content, porosity, hydraulic conductivity)
What is the contribution of chemistry in the canopy air space to ozone dry deposition?	NO and NO2 fluxes, highly reactive BVOC fluxes, same as * to obtain residual ecosystem-scale nonstomatal conductance	fluxes of oxidation products
How do snow-covered surfaces influence ozone dry deposition?	horizontal and vertical extent of snow cover, snow age	snow impurities and NO content of snowpack