Daily weather data file for Arctic Tundra LTER site at Toolik Lake. Included are daily averages and/or maximums and minimums of air, soil and lake temperature, wind speed, vapor pressure, and sum of global radiation and unfrozen precipitation recorded near Toolik Lake.
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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, 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 Imnavait weather station,12 kilometers away and 200 meters higher, is also used to fill in data gaps. Regressions of summer air temperature beween 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 2000DLTDAT.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. Data logger stopped during winter, 24Nov2000 to 2Jun2001; using Wet sedge data logger to estimate 1 and 5 meter temperatures (regressed available 1 and 5 meter temperatures with wet sedge 3 meter temperatures). Imnavait rain gage used for precipitation.
VAPOR PRESS 5M:
Daily average of the following hourly calculation.
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))
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
Log of changes:
Fall 2001 Added the winter data and estimated the missing data. JL.
For Archival Use:
DATE RECEIVED: 3May2000-25Aug2000
DATA FILE ENTERED BY: Jim Laundre
DATA FILE VALIDATION:
Version 3: Metadata updated to newer form (with sites sheet). Units updated to current standards. Discrepancy with variable names fixed. CH April 2013.
Version 4: Corrected Distrubution URL. It had xlsfiles in the path. Jim L 19Jun14
Version 5: Changed Distrubution URL since the LTER network DAS system is being discontinued. JimL 9Apr2015
Download a comma delimited (csv) or Excel file (includes metadata and data sheets).
Use of the data requires acceptance of the data use policy --> Arctic LTER Data Use Policy
To cite this data set see the citation example on the LTER Network Data Portal page for this data set.