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. Lake temperature and depth sensors are located about 4 meters offshore on a short pipe imbedded in the lake bottom. Therefore lake temperature is measured at whatever depth the lake depth sensor indicates. Both sensors are about 20 cm from the lake bottom. Soil temperatures consists of two profiles in a moss dominated plant community. They are within 3 meters of the weather station.
The hourly data are in the file 91DLTLH.DAT, the three hourly data are in 91DLTLO.DAT, and daily summaries are in 91DLTLD.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 91DLTDAT.ZIP which is archived at The Marine Biological Lab, Woods Hole, MA.

Notes: The datalogger stopped collecting data during winter of 1990-91. This file has data from April through December of 1991. A nearby station, Tussock Station, can used as a substitute for some of the weather data. See 90DLTUH.DOC and 91DLTUH.DOC.