############################################################################## # ISLSCP II Carbon Dioxide Flux at Harvard Forest and Northern BOREAS Sites # ############################################################################## File Naming Convention ---------------------- The files in this data set contain gap-filled flux data and associated meteorological data acquired from two flux tower sites from the FLUXNET global network: Harvard Forest (1992-1995) and the BOReal Ecosystem- Atmosphere Study (BOREAS) Northern Study Area (NSA), Old Black Spruce (OBS) site (1994-1995). There are 6 *.zip data files with this data set called fluxnet_xx_YYYY.zip, where: xx is the site identifier (HV=Harvard Forest; NB=BOREAS NSA OBS),and YYYY is the four-digit year. Within each yearly archive there is a set of 20 files for flux data and 5 for associated meteorology data. The data files are named using the following naming convention: fluxnet_xx_aa_bb_cc_YYYY_flx.csv for fluxes fluxnet_xx_cc_YYYY_met.csv for meteorological data where 'fluxnet' identifies this data set 'xx' is the site identification (see above) 'aa' refers to 3 basic data filling methods: re = nonlinear regression lu = look up tables dc = mean daily courses 'bb' refers to the data pre-processing methods: u0 = u* corrected u1 = no correction applied 'cc' refers to the temporal resolution: hh = half hourly dd = daily ww = weekly mm = monthly yy = yearly 'YYYY' is the 4-digit year code, e.g., "1994" ############################################################################## ASCII File Format ----------------- All of the files in the ISLSCP Initiative II data collection are in the ASCII, or text format. These files have a variable number of columns and rows, with all columns separated by a comma. Note that the number of columns in the half-hourly data is different than that for all the other data. Both numerical and text fields are included as described below. Each file contains two header lines, the first with the variable abbreviation and the second with the units of measurement. A value of -9999 denotes a missing numerical value. For each variable either sum or average/minimum/maximum, percent of gaps filled and standard deviation (S.D.) are provided. The S.D. is the standard deviation calculated from the respective daily sum or daily mean. ############################################################################ File Contents: ------------- 1) Half-Hourly Flux Data ------------------------ Variable Description -------- ----------- Day Julian Day Hour Decimal time of day (end of interval) NEE Net ecosystem exchange (FC+storage+correction if applied) in micromolm-2s-1 NEEx Index value for a respective variable indicates the status of the reported half-hourly value: 0= Original Value 1=Missing in original 2=Rejected from original 3=Filled by value from secondary instrument 4=Last second removes by data provider LE Latent heat in Wm-2 LEx See NEEx H Sensible heat in Wm-2 Hx See NEEx G Soil heat flux in Wm-2 Gx See NEEx 2) Daily, Weekly, Monthly and Yearly Flux Data ---------------------------------------------- Variable Description -------- ----------- Date Julian day for "dd" files, Week number for "ww", Month number for "mm" files. Not included in "yy" files Interval "tot","day", "night" refer to total day, daytime only, nighttime only NEE Sum of net ecosystem exchange (FC + storage + correction if applied) for time period in gC m-2 day-1 (or week-1 or month-1 or year-1) NEEx Index value for a respective variable indicates the status of the reported half-hourly value: 0=Original Value 1=Missing in original 2=Rejected from original 3=Filled by value from secondary instrument 4=Last second removes by data provider NEE_g Percent gaps filled for period NEE_s S.D. in NEE in gC m-2 day- LE Sum of latent heat for time period in MJ m-2 day-1 (or week-1 or month-1 or year-1) LE_e Error (+/-) introduced by filling for LE in MJ m-2 day-1 (or week-1 or month-1 or year-1) LE_g Percent gaps filled for period LE_s S.D. in LE in MJ m-2 day-1 H Sum of sensible heat for time period in MJ m-2 day-1 (or week-1 or month-1 or year-1) H_e Error (+/-) introduced by filling for H in MJ m-2 day-1 (or week-1 or month-1 or year-1) H_g Percent gaps filled for period H_s S.D. in H in MJ m-2 day-1 G Sum of soil heat flux for time period in MJ m-2 day-1 (or week-1 or month-1 or year-1) G_e Error (+/-) introduced by filling for G ("zero" in this version) in MJ m-2 day-1 (or week-1 or month-1 or year-1) G_g Percent gaps filled for period G_s S.D. in G in MJ m-2 day-1 3) Half-Hourly Meteorological Data ---------------------------------- Variable Description -------- ----------- Day Julian Day Hour Decimal time of day (end of interval) Rg Global radiation in Wm-2 Rgx Index value for a respective variable indicates the status of the reported half-hourly value: 0=Original Value 1=Missing in original 2=Rejected from original 3=Filled by value from secondary instrument 4=Last second removes by data provider PAR Photosynthetically active radiation in micro mole quantum m-2 s-1 PARx See Rgx Ta Air temperature (tower top) in degrees C Tax See Rgx Ts Soil temperature (5 cm depth) in degrees C Tsx See Rgx RH Relative humidity (tower top) in % RHx See Rgx VPD Vapor pressure deficit (tower top) in kPa VPDx See Rgx Ca CO2 concentration in air (tower top) in ppm Cax See Rgx Rn Net radiation in Wm-2 Rnx See Rgx PPT Precipitation in mm PPTx See Rgx SWC Soil water content in cm3 H2O/cm3 soil SWCx See Rgx WS Wind speed in ms-1 WSx See Rgx Pa Air pressure in kPa Pax See Rgx u* Friction velocity in ms-1 u*x See Rgx 4) Daily, Weekly, Monthly and Yearly Meteorological Data -------------------------------------------------------- Variable Description -------- ----------- Date Julian day for "dd" files, Week number for "ww", Month number for "mm" files. Not included in "yy" files Int. "tot","day", "night" refer to total day, daytime only, nighttime only Rg Sum of Global radiation for time period in MJ m-2 day-1 (or week-1 or month-1 or year-1) Rg_g Percent gaps filled for period Rg_s S.D. in Rg in MJ m-2 day-1 PAR Sum of Photosynthetically active radiation for time period in mol m-2 day-1 (or week-1 or month-1 or year-1) PAR_g Percent gaps filled for period PAR_s S.D. in PAR in mol m-2 day-1 Ta Average Air temperature (tower top) of time period in degrees C Ta_g Percent gaps filled for period Tami Minimum Air temperature of time period in degrees C Tamx Maximum Air temperature of time period in degrees C Ta_s S.D. of Ta in degrees C Ts Average Soil temperature (5 cm depth) of time period in degrees C Ts_g Percent gaps filled for period Tsmi Minimum Soil temperature of time period in degrees C Tsmx Maximum Soil temperature of time period in degrees C Ts_s S.D. in Ts in degrees C RH Average relative humidity (tower top) of time period in % RH_g Percent gaps filled for period RHmi Minimum relative humidity of time period in % RHmx Maximum relative humidity of time period in % RH_s S.D. in RH in % VPD Average vapor pressure deficit (tower top) of time period in kPa VPD_g Percent gaps filled for period VPDmi Minimum vapor pressure deficit of time period in kPa VPDmx Maximum vapor pressure deficit of time period in kPa VPD_s S.D. in VPD in kPa Ca Average CO2 concentration in air (tower top) of time period in ppm Ca_g Percent gaps filled for period Cami Minimum CO2 concentration in air of time period in ppm Camx Maximum CO2 concentration in air of time period in ppm Ca_s S.D. in Ca in ppm Rn Sum of Net radiation for time period in MJ m-2 day-1 (or week-1 or month-1 or year-1) Rn_g Percent gaps filled for period Rn_s S.D. in Rn in MJ m-2 day-1 PPT Sum of precipitation in mm day-1 (or week-1 or month-1 or year-1) PPT_g Percent gaps filled for period PPT_s S.D. in PPT in mm day-1 SWC Average Soil water content in cm3 H2O/cm3 soil SWC_g Percent gaps filled for period SWC_s S.D. in SWC in cm3 H2O/cm3 soil WS Average wind speed in ms-1 WS_g Percent gaps filled for period WS_s S.D. in WS in ms-1 Pa Average air pressure in kPa Pa_g Percent gaps filled for period Pa_s S.D. in Pa in kPa U* Average Friction velocity in ms-1 U*_g Percent gaps filled for period U*_s S.D. in u* in ms-1 ################################################################################