eddyTOW

The eddyTOW EC system is mounted at REA scaffold tower, about 30 m away from the 127 m tall mast. Turbulent fluxes of momentum, sensible and latent heat, carbon dioxide and ozone are measured since Aug 2001. EC system is mounted at 23 m above the ground, and it includes the three dimensional ultrasonic anemometer Gill Solent HS for measuring the wind velocity components (u, v, w) and the sonic temperature (Ts), the closed-path gas analyser Licor 6262 for measuring CO2 and H2O mixing ratio and the fast response chemiluminescence gas analyser LOZ-3, Unisearch Associates Inc, Canada for measuring ozone concentration.

The main sample line, common to Licor and LOZ-3 analysers, is 10 m long and the outside/inside diameter is 10/8 mm. The tube material is entirely (PTFE) Teflon.  A 1.0 µm pore size membrane filter (Gelman Acro 50, PTFE element, polypropylene support plate and housing, Pall Corporation, East Hills, NY, USA) recommended by LiCor Inc., is used at the inlet of the LI-6262 analyser to keep clean its measurement cell.

The sample line is heated with a power of about 3.5 Wm-1 using standard floor warming cable. The flow rate inside the sampling line is 7 L min-1.The sampling frequency is 10 Hz.