Weather data has been collected at Toolik Lake (68 degrees 38'N, 149 degrees 36'W) by a Campbell 21x datalogger since June 1988. Sensors that are measured every minute and averaged or totaled every hour include: air temperature and relative humidity at 1 and 5 meters, wind speed at 1 and 5 meters, wind direction at 5 meters, global solar radiation, photosynthetically active radiation, net radiation (Fritschen type), barometric pressure, and unfrozen precipitation. Sensors measured every 10 minutes and averaged every three hours include: soil temperatures, lake temperature, lake depth, and evaporation pan depth and pan water temperature. Net radiation and pan evaporation are only measured during the summer months. The hourly data are in the file 89DLTLH.DAT, the three hourly data are in 89DLTLO.DAT, and daily summaries are in 89DLTLD.DAT. A second Campbell 21x datalogger about 700 meters from the main weather station logs air and soil temperatures and photosynthetically active radiation in the experimental treatment plots. Treatments include greenhouse, shading, and fertilization. In the control plot wind speed and direction, global solar radiation and unfrozen precipitation are also measured. This station is also used as a backup to the main weather station. The full description of the sensors and site is in file SENSORS.DOC. The original data is in file 89DLTDAT.ZIP, which is archived at The Marine Biological Lab, Woods Hole, MA.

Notes: Lake temperature is measured near the lake depth sensor. Therefore the lake depth measurements give the depth at which lake temperature is measured. Toolik lake depth is from the lake surface to the depth of the sensor, which is mounted on the near-shore bottom at approximately 2 meters depth. Soil temperatures consist of a profile in a moss dominated plant community within 3 meters of the weather station. Lake and the 50 and 100 cm soil thermocouples worked erratically during the winter because of a loose wire. Pan evaporation measurements are only made from June through August.