ARCTIC LTER DATABASE (1) FILE NAME: 99DLTLH (2) YEAR: 1999 (3) PI: GUS SHAVER (4) OTHERS: JIM LAUNDRE (5) BRIEF DESCRIPTION OF DATA FILE: Hourly weather data from the Arctic Tundra LTER site at Toolik Lake. The following parameters are measured every minute and averaged or totaled every hour: 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. (6) KEYWORDS: weather, temperature, radiation, wind, relative humidity (7) SITE TYPE: TERRESTRIAL (8) RESEARCH LOCATION: University of Alaska Fairbanks Toolik Field Station, North Slope of Alaska (68 degrees 37' 42"N, 149 degrees 35' 46"W) (9) EXPERIMENTAL DESIGN AND METHODS: 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 99DLTLH.DAT, the three hourly data are in 99DLTLO.DAT, and daily summaries are in 99DLTLD.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. Treatmen (10) NOTES AND COMMENTS: Wind Speed less than .447 is considered calm. Lake quantum stopped working in winter 1991 and was reinstalled just for the summer of 1998,1999. In August the Lake quantum sensor was not cleaned. Therefore the values are low. Quantum has an offset of -1.4 to -2.7. The data is not corrected. For the global solar radiation and photosynthetically active radiation sensors no attempt is made to correct for frost or snow on the sensors during the winter months. Therefore winter radiation data should be view as suspect and used only qualitatively. Barometric pressure sensor was erratic for a few days in January for unknown reasons. Values were corrected. It was replaced 16Aug99. I August 1998 the tipping rain gage was fitted with a Campbell CS705 adapter for measuring snow. A Wyoming wind shield was build for the precipitation gage 30Aug99. See additional notes under Comments variable. (11) VARIABLE DESCRIPTION: NOTE: All missing values are indicated by a #N/A. Variable Variable Description Units ------- ------------------------ -------- YEAR Year in yyyy DATE Date of collection dd-mmm-yyyy MONTH Month of collection integer Days Julian plus fraction of day integer ID Datalogger program step. integer JULIAN Julian Day ddd HOUR Time in Alaska standard time 2400 format RAIN Rainfall mm PYRANOMETER Sun + sky radiation(LI-200SB) kilowatts/m2 LAKE QUANTUM QUANTUM Lake quantum sensor micromols/m2/sec QUANTUM Quantum sensor micromols/m2/sec AIR TEMP 1M Air temp at 1 meters in Celsius AIR TEMP 5M Air temp at 5 meters in Celsius RH 1M Relative humidity at 1 meters percent RH 5M Relative humidity at 5 meters percent BAROMETER Barometer readings mm hg WIND SP 1M Wind Speed at 1 meters meters/sec AIR TC 1m Air temp at 1 meter, Celsius AIR TC 5M Air temp at 5 meter, Celsius WIND SP 5M Wind Speed at 5 meters in meters/sec WIND MAG 5M Wind vector magnitude at 5m meters/sec WIND DIR 5M Wind direction at 5 meters degrees WIND STD 5M Wind direction standard deviation at 5 meters VAPOR PRESS 5M Vapor Pressure at 5 meters millibars PYR J CM2 HR Total joules per sq cm joules/cm2/hr integrated over an hour WIND SECTOR Compass direction of WIND DIR 5M 45 degree sectors DATE Stowaway The date and hour of the stowaway logger. dmm/dd/yy hr:mm. Stowaway 1M Air temperature measured with a Stowaway logger at 1 meter in the same radiation shield. Celsius Comments Comments (12) CALCULATIONS variable Formula DAYS : JULIAN + (HOUR/2400) VAPOR PRESS 5M: 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). TOTAL J CM2 HR: PYRANOMETER * 0.3600 jcm2 * 1000 Watt/Kwatt WIND MAG 5M Wind vector magnitude at 5m meters/sec WIND DIR 5M Wind direction at 5 meters degrees WIND STD 5M Wind direction standard deviation at 5 meters VAPOR PRESS 5M Vapor Pressure at 5 meters millibars PYR J CM2 HR Total joules per sq cm joules/cm2/hr integrated over an hour WIND SECTOR Compass direction of WIND DIR 5M 45 degree sectors DATE Stowaway The date and hour of the stowaway logger. dmm/dd/yy hr:mm. Stowaway 1M Air temperature measured with a Stowaway logger at 1 meter in the same radiation shield. Celsius Comments Comments (12) CALCULATIONS variable Formula DAYS : JULIAN + (HOUR/2400) VAPOR PRESS 5M: 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). TOTAL J CM2 HR: PYRANOMETER * 0.3600 jcm2 * 1000 Watt/Kwatt (13) FOR MORE INFORMATION, CONTACT: Jim Laundre or Gus Shaver, Marine Biological Laboratory, The Ecosystems Center, 7 MBL St.,Woods Hole, MA 02543, (508) 548-3705 (14) OTHER DATA FILES TO REFERENCE: 88DLTLH2, 89DLTLH2, 89DLTLH1, 89DLTLH4, 90DLTLH3, 90DLTLH, 91DLTLH, 92DLTLH, 93DLTLH, 94DLTLH, 95DLTLH, 96DLTLH, 97DLTLH (15) REFERENCE CITATIONS: Buck, A.L.. 1981 New equations for computing vapor pressure and enhancement factor. Journal of Applied Meteorology 20:1527-1532. (16) FORMAT OF VARIABLES: File Name: 99DLTLH.DAT File Type: Comma delimited (17) NUMBER OF RECORDS: (18) STATUS: Type 1 ========================================= (19) FOR ARCHIVAL USE: DATE RECEIVED: June 1999 DATA FILE ENTERED BY: Jim Laundre DATA FILE VALIDATION: NAME: Jim Laundre DATE:14OCT99 LOG OF CHANGES AND COMMENTS: