Closed Chambers
Closed chamber set-up with photo-acoustic field gas monitor Innova 1412
Fifteen closed chamber flux measurement microsites are installed in close proximity to the eddy covariance tower along a polygon rim and in four different polygons that are typical for the eddy covariance footprint. These polygons are in different stages of development with one being a high center polygon and all feature different water levels and vegetation.
The chambers consist of a 50x50 cm PVC base inserted about 10 cm into the active layer. A water-filled channel on top of the base provides a gas tight seal between the base and the actual chamber. Four ports on top of the PVC chambers are used to draw sample air as well as to circulate the air inside the chamber with an external pump. The chamber volume is 12.5 liters. 37.5 liter chambers are used where higher vegetation does not allow the use of the small chambers. Dark PVC chambers are used for measurements of respiration and as transparent chambers for measurements of net carbon dioxide flux and methane flux.
Gases are analyzed simultaneously and continuously by photo-acoustic infrared spectroscopy using an Innova AirTech Instruments Multi-gas Monitor Type 1412 with optical filters for CO2, H2O, and CH4.
For further information: Torsten Sachs