A Campbell CR21x datalogger, in the LTER acidic experimental plots (block 2), is used to monitor weather and soil temperatures.
Sensors in the control plot include: global solar radiation, photosynthetically active radiation, unfrozen precipitation, air temperature, relative humidity, wind speed, and wind direction at 3 meters. Additional seasons in greenhouses and shade houses plots measure air temperature, relative humidity and photosynthetically active radiation during the growing season. These sensors are read every minute and averaged or totaled every hour.
Two profiles of soil temperature are measured per treatment plot with copper/constantin thermocouple wires (TC) installed at depths of 10, 20, and 40 cm in inter-tussock areas. The following label codes are used: CT = control, GH = greenhouses, SH = shade houses, F = fertilized, GF= greenhouse fertilized, SF = shade house fertilized, plus a 1 or a 2 for the profile number. All soil sensors are read every 15 minutes and averaged every 3 hours.
Hourly, three hourly and daily summaries are in files yyDLTUH.DAT, yyDLTUO.DAT, and yDLTUD.DAT respectively, where yy is the year in which the data are collected. The original data are in file yyDLTDAT.ZIP which is archived at The Marine Biological Lab, Woods Hole, MA.
Note: The covers on greenhouses and shade houses are removed every fall and reinstalled every spring.

Notes: The data logger failed in winter 91-92. Battery voltage dropped below 9 volts. Last day collected was 1991 Julian 313. A new 21x was installed and the old one sent to be serviced. An error was made when setting up the new program - minute readings was averaged every minute. As a result data overflowed the memory and only one day worth of data was saved. The problem was corrected 1992 Julian 193. Lost data when battery dropped below 9 volts on Julian 244.
Soil temperatures are problematic since frost heaving of the probes caused depth of measurements to change. Missing values are indicated by #N/A. Only unfrozen precipitation is reported. Wind speeds less then 0.447 are considered calm. For the global solar radiation sensors no attempt is made to correct for frost or snow on the sensors during the winter months. Therefore winter radiation data should be view as suspect and used only qualitatively. The control and shade RH sensor are faulty, never getting above 82%. Data are report but not used in vapor pressure calculation.

Reference Citations: Buck, A.L. 1981 New equations for computing vapor pressure and enhancement factor. Journal of Applied Meteorology 20:1527-1532.

Sampling Description.

DAYS: JULIAN + (HOUR/2400)

Control plot soil thermocouples CT1 are in a E.vag tussock a tindicated depth. CT2 are in a moss inter-tussock area at indicated depth Greenhouse soil thermocouples GH1 are in a E.vag tussock at indicated depth. GH2 are in a moss inter-tussock area at indicated depth Shadehouse soil thermocouples SH1 are in a E.vag tussock at indicated depth. SH2 are in a moss inter-tussock area at indicated depth Fertilized plot soil thermocouples F1 are in a E.vag tussock at indicated depth. F2 are in a moss inter-tussock area at indicated depth Greenhouse fertilized soil thermocouples Celsius GF1 are in a E.vag tussock at indicated depth. GF2 are in a moss inter-tussock area at indicated depth Shadehouse fertilized soil thermocouples Celsius SF1 are in a E.vag tussock at indicated depth. SF2 are in a moss inter-tussock area at indicated depth