Eddy233

The "Eddy233" EC system is mounted on the 127 tall mast. Turbulent fluxes of momentum, sensible and latent heat, carbon dioxide and aerosol particles are measured since 1996. EC system is located at 23.3 m nominal height in the mast (24-25 m above the ground), and it includes the three dimensional ultrasonic anemometer Gill Solent R2 for measuring wind velocity components (u, v, w) and sonic temperature Ts, the closed-path gas analyser Licor 6262 for measuring CO2 and H2O mixing ratio and the CPC_3010 for measuring aerosol particle number concentration.

The sample line is 7 m long and the outside/inside diameter is 6/4 mm. Until May 2002 the tube material was entirely (PTFE) Teflon. On 9th May 2002 the sample line was renewed and the old tube was replaced with an electro polished seamless stainless steel tube.  At the end of the line in front of the LI-6262 analyser an about 0.5 m long piece of new Teflon tube was, however, installed to provide necessary flexibility to the line.  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 5 Wm-1 using standard floor warming cable. The heating power creates in practice an increase of a couple of ºC in the sample air temperature. The flow rate inside the sampling line is 6.1 L min-1.The sampling frequency is 20.833 Hz, but the rawdata are saved as 10.411 Hz in 30 min binary files.