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, 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 88DLTLH.DAT, the three hourly data are in 88DLTLO.DAT, and daily summaries are in 88DLTLD.DAT. The full description of the sensors and site is in file
SENSORS.DOC. The original data is in file 88DLTDAT.ZIP which is
archived at The Marine Biological Lab, Woods Hole, MA.

Notes: Wind speed less than .447 is considered calm .
Radiation data were 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.
From June 1 to August 24 the 5 meter sensor was only at 3 meters. On August 24th the 3 meter temperature/ RH sensor was moved up to 5 meters for better separation for the possibility of calculating energy balance using Bowen ratio approach. For the winter, only the 5 meter temperature/RH, wind speed and direction, soil temperature, and lake temperature were recorded. For 5 meter air temperatures less then -40, a regression of 5 meter air temperature verse air TC (only used 0 to -35 for regression) was used to correct the air temperatures. The 5 meter air thermister is only accurate to -40 Celsius.
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 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 away and 200 meters higher).