Iced sunshine pyranometer SPN1 in front of snow-covered spruces at Wetzstein (Thuringian Slate Mountains), gray sky in the background. The ice has grown with the wind direction and has beautiful bizarre shapes. One could believe it is a black-and-white picture. However, at the lower right edge of the picture you can see a very small red part of the measuring tower.

Wetzstein (Germany)

Athmospheric long-term measurements above a spruce monoculture in the Thuringian Slate Mountains

Description & History

The station was built in 2001 in a forest with pure spruce stand, in the so-called Slate Mountains in the Thuringian Forest.

The power supply of the system is done by a 230 V power line from the vicinity of the Altvaterturm.

At the measuring point there is an aluminum tower from old Bundeswehr stock (1.8 m x 1.37 m x 1.83 m). It is 30 m high and rises 8 m above the treetops.

In 2005, the station was part of the so-called Advex experiment. Since advection exerts a very large influence on the correct calculation of CO2 fluxes, especially at night, the purpose of the experiment was to find alternatives for correcting the night-time Eddy covariance (EC) measurements and their resulting CO2 budgets.

The second Eddy tower, which was set up from April 2006 to July 2012, was used to explore the influence of the distinct topography.


Spruce forest
Tree height 24 m
Latitude: 50,45
Longitude: 11,46
Elevation: 781 m a.s.l.    


  • Since 2001 until today
  • Eddy Covariance
  • Meteorology
  • Sap flow
  • Tree increment
  • Tree temperature
  • Advex experiment 2006
  • Second Eddy tower from April 2006 to July 2012



Variables & Instruments


  • Eddy covariance - CO2, water vapor, momentum, heat flux (Gill R3, LI6262)
  • Profile at 9 altitudes - CO2 (LI610)


  • Wind speed and direction - 2D ultrasonic anemometer, Thies
  • Air pressure - pressure transducer PTB101B, Vaisala
  • Air temperature and humidity - temperature-humidity sensor KPC1_5-ME, Mela
  • Air temperature - ventilated thermometer Frankenberger, Friedrichs
  • Precipitation - heated tipping bucket precipitation gauge, Thies
  • Solar radiation - radiation balance sensor CNR1, Kipp & Zonen
  • Terrestrial radiation - radiation balance sensor CNR1, tilt & zones
  • Photosynthetically Active Radiation - PAR Sensor PAR Lite, Tilt & Zones
  • Global & diffuse radiation and sunshine duration - Sunshine Pyranometer SPN1, tilt & zones
  • Surface Temperature - Infrared Thermometer KT15, Heitronics

Soil conditions

  • Soil temperature in 2 profiles - Soil temperature sensor PT100, DIY
  • Soil moisture at 6 locations - Theta soil moisture probe ML-2x, Delta-T
  • Soil heat flux at 5 positions - Soil heat flux plates HP3/CN3, Rimco

Tree conditions

  • Trunk temperatures at different depths - NTC temperature sensors, Campbell Scientific
  • Tree growth - Dendrometer
  • Sap flow

Data acquisition

  • Meteorological data - Data logger CR23X, Campbell Scientific
  • CO2 profile data - Data logger CR10X, Campbell Scientific
  • River data - notebook
  • Vegetation - digital camera
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