Weather data has been collected at Toolik Lake by a Campbell 21x data logger 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, 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 yyyyDLTLH.DAT, the three hourly data are in yyyyDLTLO.DAT, and daily summaries are in yyyyDLTLD.DAT. A second Campbell 21x data logger 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 Imnavait weather station,12 kilometers away and 200 meters higher, is also used to fill in data gaps. Regressions of summer air temperature between Inmavait and with Toolik are good but during the winter months there is greater variability. This station is maintained by Larry Hinzman and Doug Kane, Water Research Center; University of Alaska Fairbanks; Fairbanks, AK 99775-5860. Precipitation data from the Natural Resources Conservation Service (NRCS) Alaska Imnavait weather station is also used to fill in the data gaps. Please contact Rick McClure, Data Collection Officer, Natural Resources Conservation Service, 949 E. 36th Ave., Suite 400,, Anchorage, AK 99508-4362, (907) 271-2424 for more details.
The full description of the sensors and site is in file SENSORS.DOC. The original data is in file yyyyDLTDAT.ZIP, which is archived at The Marine Biological Lab, Woods Hole, MA.

Notes: Wind speed less than .447 is considered calm.
Radiation data was not totaled for the winter months since no attempt was made to keep sensors snow and frost free. Lake temperature is measured near the lake depth sensor. Therefore the lake depth measurements give the depth at which lake temperature is measured.
Battery lost connection with logger and no data was collected from 24Nov 2000 to June 2001; The StowAway sensor was used to estimate the 1 meter air temperature and a regression between 1 m and 5m to estimate the 5 meter air temp. Where StowAway was missing or temperatures dropped below -37.2 the Wet Sedge air temperature was used.
From 4 Jun02 through 23Aug02 replaced 5 meter vapor pressure calculation with 1 meter. The 5 meter RH sensor was not working.

Sampling Description.

None