30 Minute ISFS Data for SOAS
These data contain surface meteorology measurements of the Integrated Surface Flux System (ISFS) during the Southern Oxidant and Aerosol Study (SOAS), at the Alabama Aquatic Biodiversity Center (AABC), during May, June and July of 2013.
For general information about the operations of the ISFS during SOAS see https://www.eol.ucar.edu/field_projects/soas.
The ISFS 30 minute dataset contains some of the first and second moments of variables measured by the NCAR ISFS during SOAS, in addition to derived calculations of the fluxes of sensible and latent heat, friction velocity, surface heat flux and net radiation.
The data are stored in NetCDF files. Information on the NetCDF file format and software is available at http://www.unidata.ucar.edu/software/netcdf/. Information specfic to ISFS NetCDF files is available at https://www.eol.ucar.edu/content/isfs-netcdf-files.
NetCDF File Names
Each NetCDF file contains one week of data. The file names are of the form "isfs_YYYYMMDD.nc", where YYYYMMDD is the year, month and day in UTC of the start of the data.
See the table at the bottom of this page for a partial listing of the variables in the file. The second moments are not listed in that table.
See the table at https://www.eol.ucar.edu/content/soas-isfs-page for information on the sensors that were deployed.
The base_time variable contains one value, the time of the start of the file, as a number of POSIX (non-leap) seconds since 1970 Jan 1, 00:00 UTC.
Values for each time-varying measurement will be found in the NetCDF files, as a variable with a time dimension. The time dimension for a file containing a full week of data will be 336, the number of 30 minute periods in a week.
The time variable contains the time to be associated with each sample, in units of seconds since base_time, or 00:00 UTC of the day. Each time value is the middle of the averaging period, and will have values of 900 (00:15:00 UTC), 2700 (00:45:00), etc, up to 86250 (23:45:00 UTC).
The NetCDF dimensions in each file are:
|time||up to 336||number of 30 minute periods in a week|
|site||2||index for the ISFS sites at SOAS, the 45 meter tower and the pond site|
|layout||2||index to indicate one of two station layouts.|
Short Name Attributes
Each measured variable will have a short_name NetCDF attribute. The field before the first period in the short_name is a generic variable name, such as T for temperature, Rsw for short wave radiation, or u for the U component of the wind. For second moments, such as variances and co-variances, the first field of the short_name will contain single quote marks after a variable to indicate it is an average of a deviation. For example, a leading short name of w'tc', indicates the quantity is an average of (w-mean(w)) * (tc-mean(tc)), where mean(x) is the 5 minute mean of the variable x, w is the vertical wind component, and tc is the temperaure from the speed of sound.
For each of the 3-D sonic anemometers, the following second moments in u,v,w and tc are provided for the computation of eddy-correlation fluxes. Scalar values such as water vapor density and carbon dioxide were also measured at the same locations. kh2o is a water vapor measurement from a Campbell krypton hygrometer at 2 and 13.9 meters on the AABC tower. h2o and co2 are water vapor and carbon-dioxide measurements from LICOR 7500 gas analyzers at 8, 20, 26, 32 and 43.9 meters, and from a Campbell Scientific EC150 IRGA at 38 meters.
The height in meters above ground of the measurement, if appropriate, will be indicated in a second field after a period in the short_name, for example RH.26m, or u'tc'.38m.
The actual NetCDF variable names will have underscores, '_', in place of periods and single quotes. Therefore a variable with a short_name attribute of w'co2'.38m will have a NetCDF variable name of w_co2__38m.
Units and Long Names
Each variable will have NetCDF attributes containing the units of the measurement, and a long name giving more information on the measurement.
Variables from sensors used in eddy-covariance flux measurements will have a counts attribute indicating the number of samples that were included in each statistic.
The missing data value is 1x10^37. A missing value indicates either that nothing was measured at the location indicated in the variable name and station index, or the sensor was not reporting at the given time, or it was detemined that the data value did not meet QC criteria during post-project analysis.
Table of NetCDF Variables
The following is a partial listing of the variables in the NetCDF files. It does not contain the second moments.
|NetCDF name||ISFS short name||Units||Dimensions||Long Name|
|u_2m||u.2m||m/s||time||Wind U component from CSAT3|
|v_2m||v.2m||m/s||time||Wind V component from CSAT3|
|w_2m||w.2m||m/s||time||Wind W component from CSAT3|
|tc_2m||tc.2m||degC||time||Virtual air temperature from speed of sound, CSAT3|
|kh2o_2m||kh2o.2m||g/m^3||time||CSI Krypton water vapor|
|T_2m||T.2m||degC||time||Air Temperature from NCAR hygrothermometer|
|RH_2m||RH.2m||%||time||Relative Humidity from NCAR hygrothermometer|
|H_2m||H.2m||W/m^2||time||Sensible heat flux|
|LE_2m||LE.2m||W/m^2||time||Latent heat flux|
|rhoDry_2m||rhoDry.2m||kg/m^3||time||Density of dry air|
|p_8m||p.8m||mb||time||Barometric Pressure, Paroscientific 6000|
|u_8m||u.8m||m/s||time||Wind U component from CSAT3|
|v_8m||v.8m||m/s||time||Wind V component from CSAT3|
|w_8m||w.8m||m/s||time||Wind W component from CSAT3|
|tc_8m||tc.8m||degC||time||Virtual air temperature from speed of sound, CSAT3|
|h2o_8m||h2o.8m||g/m^3||time||LICOR 7500 water vapor density|
|co2_8m||co2.8m||g/m^3||time||LICOR 7500 CO2 density|
|T_8m||T.8m||degC||time||Air Temperature from NCAR hygrothermometer|
|RH_8m||RH.8m||%||time||Relative Humidity from NCAR hygrothermometer|
|lidiag_8m||lidiag.8m||time||LICOR 7500 diagnostic value|
|u_13_9m||u.13.9m||m/s||time||Wind U component from CSAT3|
|v_13_9m||v.13.9m||m/s||time||Wind V component from CSAT3|
|w_13_9m||w.13.9m||m/s||time||Wind W component from CSAT3|
|tc_13_9m||tc.13.9m||degC||time||Virtual air temperature from speed of sound, CSAT3|
|kh2o_13_9m||kh2o.13.9m||g/m^3||time||CSI Krypton water vapor|
|T_13_9m||T.13.9m||degC||time||Air Temperature from NCAR hygrothermometer|
|RH_13_9m||RH.13.9m||%||time||Relative Humidity from NCAR hygrothermometer|
|p_20m||p.20m||mb||time||Barometric Pressure, Paroscientific 6000|
|u_20m||u.20m||m/s||time||Wind U component from CSAT3|
|v_20m||v.20m||m/s||time||Wind V component from CSAT3|
|w_20m||w.20m||m/s||time||Wind W component from CSAT3|
|tc_20m||tc.20m||degC||time||Virtual air temperature from speed of sound, CSAT3|
|h2o_20m||h2o.20m||g/m^3||time||LICOR 7500 water vapor density|
|co2_20m||co2.20m||g/m^3||time||LICOR 7500 CO2 density|
|T_20m||T.20m||degC||time||Air Temperature from NCAR hygrothermometer|
|RH_20m||RH.20m||%||time||Relative Humidity from NCAR hygrothermometer|
|lidiag_20m||lidiag.20m||time||LICOR 7500 diagnostic value|
|u_26m||u.26m||m/s||time||Wind U component from CSAT3|
|v_26m||v.26m||m/s||time||Wind V component from CSAT3|
|w_26m||w.26m||m/s||time||Wind W component from CSAT3|
|tc_26m||tc.26m||degC||time||Virtual air temperature from speed of sound, CSAT3|
|h2o_26m||h2o.26m||g/m^3||time||LICOR 7500 water vapor density|
|co2_26m||co2.26m||g/m^3||time||LICOR 7500 CO2 density|
|lidiag_26m||lidiag.26m||time||LICOR 7500 diagnostic value|
|T_26m||T.26m||degC||time||Air Temperature from NCAR hygrothermometer|
|RH_26m||RH.26m||%||time||Relative Humidity from NCAR hygrothermometer|
|u_32m||u.32m||m/s||time||Wind U component from CSAT3|
|v_32m||v.32m||m/s||time||Wind V component from CSAT3|
|w_32m||w.32m||m/s||time||Wind W component from CSAT3|
|tc_32m||tc.32m||degC||time||Virtual air temperature from speed of sound, CSAT3|
|h2o_32m||h2o.32m||g/m^3||time||LICOR 7500 water vapor density|
|co2_32m||co2.32m||g/m^3||time||LICOR 7500 CO2 density|
|lidiag_32m||lidiag.32m||time||LICOR 7500 diagnostic value|
|p_32m||p.32m||mb||time||Barometric Pressure, Paroscientific 6000|
|T_32m||T.32m||degC||time||Air Temperature from NCAR hygrothermometer|
|RH_32m||RH.32m||%||time||Relative Humidity from NCAR hygrothermometer|
|u_38m||u.38m||m/s||time||Wind U component from CSAT3|
|v_38m||v.38m||m/s||time||Wind V component from CSAT3|
|w_38m||w.38m||m/s||time||Wind W component from CSAT3|
|tc_38m||tc.38m||degC||time||Virtual air temperature from speed of sound, CSAT3|
|h2o_38m||h2o.38m||g/m^3||time||Water vapor density from CSI IRGA|
|co2_38m||co2.38m||g/m^3||time||CO2 density from CSI IRGA|
|irgadiag_38m||irgadiag.38m||time||CSI IRGA diagnostic|
|T_38m||T.38m||degC||time||Air Temperature from NCAR hygrothermometer|
|RH_38m||RH.38m||%||time||Relative Humidity from NCAR hygrothermometer|
|Rlw_in_41m||Rlw.in.41m||W/m^2||time||Incoming long wave radiation at 41 meters|
|Rlw_out_41m||Rlw.out.41m||W/m^2||time||Outgoing long wave radiation at 41 meters|
|Rsw_in_41m||Rsw.in.41m||W/m^2||time||Incoming short wave radiation at 41 meters|
|Rsw_out_41m||Rsw.out.41m||W/m^2||time||Outgoing short wave radiation at 41 meters|
|Rsum_41m||Rsum.41m||W/m^2||time||Sum of 4 components of radiation at 41 meters|
|lidiag_43_9m||lidiag.43.9m||time||LICOR 7500 diagnostic value|
|p_43_9m||p.43.9m||mb||time||Barometric Pressure, Paroscientific 6000|
|u_43_9m||u.43.9m||m/s||time||Wind U component from CSAT3|
|v_43_9m||v.43.9m||m/s||time||Wind V component from CSAT3|
|w_43_9m||w.43.9m||m/s||time||Wind W component from CSAT3|
|tc_43_9m||tc.43.9m||degC||time||Virtual air temperature from speed of sound, CSAT3|
|h2o_43_9m||h2o.43.9m||g/m^3||time||LICOR 7500 water vapor density|
|co2_43_9m||co2.43.9m||g/m^3||time||LICOR 7500 CO2 density|
|T_43_9m||T.43.9m||degC||time||Air Temperature from NCAR hygrothermometer|
|RH_43_9m||RH.43.9m||%||time||Relative Humidity from NCAR hygrothermometer|
|Rlw_in||Rlw.in||W/m^2||time||Incoming long wave radiation at forest floor|
|Rlw_out||Rlw.out||W/m^2||time||Outgoing long wave radiation at forest floor|
|Rsw_dfs_spn1||Rsw.dfs.spn1||W/m^2||time||Diffuse short wave radiation at forest floor, uplooking SPN1 sensor|
|Rsw_global_spn1||Rsw.global.spn1||W/m^2||time||Global short wave radiation at forest floor, uplooking SPN1|
|Rsw_in||Rsw.in||W/m^2||time||Incoming short wave radiation at forest floor|
|Rsw_out||Rsw.out||W/m^2||time||Reflected short wave radiation at forest floor|
|Rsum||Rsum||W/m^2||time||Sum of 4 components of radiation at forest floor|
|Gsfc_a||Gsfc.a||W/m^2||time||Surface heat flux at soil site "a"|
|Gsfc_b||Gsfc.b||W/m^2||time||Surface heat flux at soil site "b"|