NOAA/CMDL 25 Nov 2002 -------------------------------------------------------------------- Tower Program data file format for station (W)LEF. Contact:Peter Bakwin or Dale Hurst or Thayne Thompson NOAA/CMDL 325 Broadway Boulder, CO 80305 Peter.Bakwin@noaa.gov Dale.Hurst@noaa.gov Thayne.M.Thompson@noaa.gov 303-497-6773 (tel) 303-497-7003 303-497-6671 303-497-6290 (fax) Tower location: 14 km east of Park Falls, Wisconsin, USA 45deg 56' 43" N latitude 90deg 16' 28" W longitude tower base altitude = 472 m above sea level local standard time (CST) = GMT - 6 hours References: Bakwin, P.S., D.F. Hurst, P.P. Tans, and J.W. Elkins, Anthropogenic sources of halocarbons, sulfur hexafluoride, carbon monoxide, and methane in the southeastern United States, J. Geophys. Res., 102, 15,915-15,925, 1997. Hurst, Dale F., Peter S. Bakwin, and James W. Elkins, Recent trends in the variability of halogenated trace gases over the United States, J. Geophys. Res., 103, 25,299-25,306, 1998. ******************** wlef_level.dat ******************** where level=2 (30 m) or level=3 (76 m) or level=6 (396 m) Data was taken from Jun 1995 until Nov 2000. Each record (row) is an instantaneous measurement of 12 unique chemicals (3 are repeated) about once every hour using Electron Capture Gas Chromatograph. Added to this are the nearest hourly average CO2, wind speed, wind direction, and air temperature for that height on the tower. There are 24 entries in each record, detailed below. Col Data Units No data c1 c2 --- ------------------------------ ------------ -------- --- --- 1 Year GMT 1 4 2 Month GMT 6 7 3 Day GMT 9 10 4 Hour GMT 12 13 5 Minute GMT 15 16 6 N2O, nitrous oxide ppb -99.9 18 22 7 SF6, sulfur hexafluoride ppt -9.99 24 28 8 N2OCO2, nitrous oxide + CO2 ppb -99.9 30 34 9 F12, dichlorodifluoromethane ppt -99.9 36 40 10 F11, trichlorofluoromethane ppt -99.9 42 46 11 F113, trichlorotrifluoroethane ppt -99.9 48 52 12 FC11, trichlorofluoromethane ppt -99.9 54 58 13 FC113,trichlorotrifluoroethane ppt -99.9 60 64 14 CHCl3, chloroform ppt -99.9 66 70 15 MC, methyl chloroform ppt -99.9 72 76 16 CT, carbon tetrachloride ppt -99.9 78 82 17 PCE, perchloroethylene ppt -99.9 84 88 18 H2, hydrogen ppb -99 90 93 19 CH4, methane ppb -99 95 98 20 CO, carbon monoxide ppb -99 100 103 21 CO2, carbon dioxide ppm -999.9 105 110 22 Wind Speed, m/s -99.9 112 116 23 Wind Direction, degrees True -999 118 121 24 Temperature, degrees C -99.9 123 127 --- ------------------------------ ------------ -------- --- --- c1 c2 refer to the columns spanned by each data value, e.g., execution under UNIX of "cut -c 18-22 wlef_3.dat" would extract the data for N2O at 76 m. Units: ppm = micromole/mole (10^-6) ppb = nanomole/mole (10^-9) ppt = picomole/mole (10^-12) Notes: Data taken Jun 1995 through May 1996 are more noisy for some chemicals and are considered poorer quality. Use with caution. This data is reported at 30-minute intervals instead of hourly.