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, 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 96DLTLH.DAT, the three hourly data are in 96DLTLO.DAT, and daily summaries are in 96DLTLD.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 96DLTDAT.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 at lake depth. Lake and 50 and 100 cm soil thermocouples stopped working during the winter of 1996 because of a loose wire. Quantum mol/m2 was corrected for negative readings by adding 500 to the daily quantum sum.
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
(Note: To correct for negative readings, 500 was added to the daily quantum sum.)
Log of changes:
10Sept97 Rechecked values
6Dec99 Updated date and year to four digits. Changed variable names to the unified names and order. JL
For Archival Use:
DATE RECEIVED: Aug1996, Jun1997
DATA FILE ENTERED BY: Jim Laundre
DATA FILE VALIDATION:
03 Sept 1996
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
Full Metadata and data files (either comma delimited (csv) or Excel) - Environmental Data Initiative repository.
Use of the data requires acceptance of the data use policy --> Arctic LTER Data Use Policy