Scale drawing of the flux tower and instrumentation.  Eddy flux instrumentation at two heights (155’ and 200’) measures fluxes and allows estimation of flux divergence; includes: Campbell CSAT3 sonic anemometer, CO2/H2O intake, and chilled mirror hygrometer (Edgetech Model 200M), used for water-vapor inter-comparison with infrared gas analyzer (Licor 6262).  Upper eddy includes a second sonic (Gill research model HS) for backup and intercomparison.  Profile instrumentation at 8 heights measures through-canopy storage of CO2, H2O and heat; it includes:  CO2/H2O intake, and aspirated thermocouple temperature sensors (MetOne).  Analyzer units (in blue) for each flux level and for the profile system, contain CO2/H2O analyzer (Licor 6262), and associated datalogging and control instrumentation.  (The three other electronics boxes -- the flow distribution solenoid box and control boxes for the 2 chilled mirror hygrometers -- are also shown in blue.)  Other instrumentation (in red) includes net radiation (220’) and PAR (220’, 50’) sensors, wind direction (220’) and wind-speed indicators (220’, 165’, 125’, 100’), and rain gauge (175’).  Not shown are soil temperature sensors (at 8 depths).