Eddy Covariance (H2O/CO2/CH4)
Eddy covariance system, Samoylov Island
Energy and trace gas fluxes on Samoylov Island are measured in the center of the island which is characterized by relatively homogenous wet polygonal tundra with a regular micro-relief due to low center ice-wedge polygons. The fetch extends for about 600 m around the eddy covariance tower and some larger lakes are located on the periphery.
For measuring wind velocity components and sonic temperature, we use the three-dimensional sonic anemometer Solent R3 (Gill Instruments Ltd., UK) installed 4 m above ground level. A vacuum pump (RB0021, Busch Inc., Germany) draws sample air through an infrared gas analyser (LI-7000, LI-COR Inc., USA) for H2O/CO2 analysis and a Tunable Diode Laser (TGA100, Campbell Scientific Ltd., USA) for CH4 analysis.
Eddy covariance gas analyzer
Before entering the Tunable Diode Laser, sample air is dried in a reversed flow membrane gas dryer (PD-200T-48 SS, Perma Pure Inc., USA). The analyzers and the gas dryer are arranged in series and housed in a temperature regulated case at the base of the tower. All analog signals are synchronously digitised at 20 Hz and logged on a laptop PC running EdiSol software (University of Edinburgh, UK). The system is powered by a diesel generator and an uninterruptable power supply.
Additional instruments installed on or near the tower include sensors for air temperature and relative humidity (MP103A, ROTRONIC AG, Switzerland), incoming and outgoing solar and infrared radiation (CNR1, Kipp and Zonen B.V., The Netherlands), photosynthetically active radiation (QS2, Delta-T Devices Ltd., UK), and barometric pressure (RPT410, Druck Messtechnik GmbH, Germany).
Other meteorological parameters are measured at the longterm climate and soil stations located a few hundred meters south of the eddy covariance system (see Samoylov soil and climate station).
For further information to the method: Eddy Covariance.
For further information: Torsten Sachs