To obtain the turbulent fluxes the eddy-correlation technique is used. The measuring system is based on a 3D ultrasonic anemometer in combination with a fast infrared gas analyser placed on the top of a 23.4 m tower. A full description of the system is given by Moncrieff et al. (1997) and Aubinet et al. (2000). In the first setup (from fall 1996 till june 2001) A Gill R2 was used in combination with a Li-Cor LI-6262 and a Campbell Krypton hygrometer KH2O. Raw data are stored at 10 Hz using a HP Palmtop PC and PCMCIA cards.
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Since july 2001 a Gill windmaster Pro is installed in combination with an open path Li-Cor LI-7500.
To determine net radiation the four components of the radiation balance are measured separately. Incoming and reflected short wave radiation are measured with two pyranometers. The long wave components are measured by pyrgeometers, with the sensor for the incoming long wave radiation being ventilated. At the top of the scaffolding tower (23.4 m) standard meteorological measurements of precipitation, horizontal wind speed, wind direction, relative humidity and air temperature are made. Soil heat flux is measured using a heat flux sensor just under the litter layer. Soil moisture and temperature is measured in two profiles at five depths. Additionally profiles (five levels) are measured of CO2 and H2O concentrations as well as wind speed and temperature.
List of instrumentation
| Variable | Instrument | Manufacturer | Type | Height in m above ground |
| Turbulence components | Sonic anemometer | Gill Instruments | Windmaster Pro | 26.0 |
| Virtual temperature | Sonic anemometer | Gill Instruments | Windmaster Pro | 26.0 |
| CO2/Specific humidity fluctuations | Infra-red gas analyser | LI-COR | LI-7500 | 26.0 |
| Incoming/outgoing short wave radiation | Pyranometer | Kipp&Zonen | CM21 | 21.9 |
| Incoming/outgoing long wave radiation | Pyrgeometer | Kipp&Zonen | CG1 | 21.9 |
| Temperature long wave radiation sensors | Platinum resistance | Kipp&Zonen | PT100 | 21.9 |
| Reflected photosynthetically active radiation | Quantum sensor | LI-COR | LI-190SZ | 21.9 |
| Direct photosynthetically active radiation | Quantum sensor | Delta-T Devices | BF-3 | 24.5 |
| Diffuse photosynthetically active radiation | Quantum sensor | Delta-T Devices | BF-3 | 24.5 |
| Air temperature | Platinum resistance | Vaisala | HMP35A | 23.5, 7.5, 5.0 |
| Air pressure | Analog barometer | Vaisala | PTB101C | 15.0 |
| Relative humidity | Capacitive sensor | Vaisala | HMP35A | 23.5, 7.5, 5.0 |
| Wind speed | Cup anemometer | Vector Instruments | A101ML | 24.4, 7.5, 5.0 |
| Wind direction | Wind vane | Vector Instruments | W200P | 24.0 |
| CO2/H2O-concentration | IRGA | PP systems | CIRAS-SC | 24.4, 7.5, 5.0, 2.5, 0.4 |
| Precipitation | Tipping bucket | EML | ARG100 | 23.8 (tower), 0.4 (open field) |
| Throughfall | Tipping bucket | IMAG-DLO | - | 1.0 |
| Soil heat flux | Thermopiles | TNO-TPD | PU43T | -0.1 |
| Soil moisture | Frequency domain | Campbell Scientific | CS616 | litter, -0.03, -0.20, -0.50, -1.0 |
| Soil temperature | Thermistor | Campbell Scientific | 107 | litter, -0.03, -0.20, -0.50, -1.0 |
| Bole temperature | Thermistor | Campbell Scientific | 107 | 4.0 |
| Groundwater level (filter depth) | -6.5, -4.8 | |||
Aubinet M., Grelle A., Ibrom A., Rannik �., Moncrieff J., Foken T., Kowalski A.S., Martin P.H., Berbigier P., Bernhofer Ch., Clement R., Elbers J.A., Granier A., Gr�nwald T., Morgenstern K., Pilegaard K., Rebmann C. , Snijders W., Valentini R., Vesala T. Estimates of the Annual Net Carbon and Water Exchange of Forests: the EUROFLUX Methodology. Adv. Ecol. Research, 30 (2000), 113-175.
Moncrieff, J.B., J.A. Elbers, & others, 1997. A system to measure surface fluxes of momentum, sensible heat, water vapour and carbon dioxide. Journal of Hydrology 188-189/89-611, special issue on HAPEX-Sahel, 1997, Elsevier Science.