In 1990 a Campbell datalogger was installed in block 2 of the Toolik LTER experimental tussock plots. Sensors were placed in a control, fertilized, greenhouse, greenhouse fertilized, shade house and shade house fertilized sites.
In each plot two strings (one in a tussock and one in a moss dominated area) of copper/copper-nickel thermocouple wires (TC) were installed at depths of 10, 20, and 40 cm. The following label codes were used: CT=control, GH = greenhouses, SH = shade houses, F=fertilized, GF= greenhouse fertilized, SF = Shade house fertilized, with a suffix of 1 for Eriophorum vaginatum tussock or 2 for moss bed. All measurements are in degree Celsius. All soil sensors were read every 15 minutes and averaged every 3 hours. During early years due to storage limitations just daily soil values were stored during the winter months.
In the control plot additional sensors include: global solar radiation, photosynthetically active radiation, unfrozen precipitation, and at 3 meters: air temperature, relative humidity, wind speed, and wind direction. In greenhouses and shade houses plots, air temperature, relative humidity and photosynthetically active radiation are also measured during the growing season. See Sensors for a detailed description of each sensor used. Each sensor is read every minute and averaged or totaled every hour.
The soil sensors have been very problematic. The sensors strings would move with freezing and thawing of the soil. Most strings were heaved up 3 - 10 cm. Soil data are being evaluated to determent the usable data and will be added when completely error checked.