Weather data has been collected at Toolik Lake (68 degrees 38'N, 149 degrees 36'W) by a Campbell 21x datatlogger 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 93DLTLH.DAT, the three hourly data are in 93DLTLO.DAT, and daily summaries are in 93DLTLD.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 93DLTDAT.ZIP which is archived at The Marine Biological Lab, Woods Hole, MA.

Notes: Wind speed less than .447 is considered calm. Data is missing for the following periods:
93014 to 93166 - Top tower blew off; 5 Meter - Temp, RH, Wind direction and Wind speed no good. Also caused 1 meter Temp, RH to be erratic from 93130-93166. Soil temperature for set 2 were out of range during the winter. Missing data for air temperature and rain were estimated when possible. For small gaps the in the hourly data before and after were averaged. For larger gaps regressions were made with the either Toolik Tussock site or Imnaviat data set (a weather station maintained by Hinzman and Kane, Water Research Center, University of Alaska Fairbanks, Fairbanks, AK 99775-5860, which is about 12 kilometers to the east and 200 meters higher).

Reference Citations:

VAPOR PRESS 5M:
Daily average of
If Air Temp > 0 then (RH 5M/100) * 6.1121 *exp(17.368 * AIR TEMP 5M/(238.88 + AIR TEMP 5M))
If Air Temp < 0 then (RH 5M/100) * 6.1121 exp(17.966 * AIR TEMP 5M/(238.88 + AIR TEMP 5M)) (Buck 1981).
PYR J CM2 : Daily sum of PYRANOMETER * 0.3600 jcm2 * 1000 Watt/Kwatt
QUANTUM Mol/m2: (Daily sum of Quantum)*60sec*60 min* 10^-6 umol/mol

Sampling Description.

Estimate of 1 meter from Imnavait 1 meter: Using a regress between Imnavait 1M to estimate AT TEMP 1M Estimate of 5 meter from Imnavait 1 meter: Using a regress between Imnavait 1M to estimate AT TEMP 5M Imnavait data (68o37'N 149o17'W) collected by Larry Hinzman and Doug Kane Water Research Center; University of Alaska Fairbanks, Fairbanks, AK 99775-5860