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 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, barometric pressure, and 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 98DLTLH.DAT, the three hourly data are in 98DLTLO.DAT, and daily summaries are in 98DLTLD.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 98DLTDAT.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 lake surface to the depth of the sensor which is mounted on the near-shore bottom at approximately 2 meters depth. June into August the lake depth sensor became erratic. It was replace August 7th but in late December it stopped working. Soil temperatures consist of two profiles in a moss dominated plant community. They are within 3 meters of the weather station. Late August 1997 soil profile #1 at 50 and 100 cm could not be reset. They were put in at 20 cm shallower. In August 1998 soil profiles were reset on a white fiberglass rod and 5, 10, 150 cm depths added. Pan evaporation measurements are only made from June through August.

Sampling Description.

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