Weather data has been collected at Toolik Lake 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 2000DLTLH.DAT, the three hourly data are in 2000DLTLO.DAT, and daily summaries are in 2000DLTLD.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 2000DLTDAT.ZIP which is archived at The Marine Biological Lab, Woods Hole, MA.

Notes: Lake temperature is measured where the lake depth measurement is made. Lake Depth sensor stopped working in December 1998. It was replaced with a temporary 2.5 psi depth sensor for the summer. In August 1999 a 5 psi sensor was installed. See notes under comment variable. Soil temperatures consist of two profiles in a moss dominated plant community. They are within 3 meters of the weather station. Evaporation pan temperature sensor was not placed in the water this summer.
Battery lost connection with logger and no data was collected from 24Nov 2000 to June 2001.

Sampling Description.

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