30 Minute Flux Dataset

Documentation of the ISFS 30 minute flux dataset for PCAPS

The ISFS 30 minute flux dataset for PCAPS contains sensible and latent heat fluxes, friction velocity, total radiation and surface heat flux, as measured by the 7 NCAR Integrated Surface Flux System (ISFS) stations during PCAPS.

The dataset consists of 4 small NetCDF files on the EOL CODIAC site.

  • pcaps30m_20101101.nc
  • pcaps30m_20101201.nc
  • pcaps30m_20110101.nc
  • pcaps30m_20110201.nc

Each file contains one month's data starting at the first of the month indicated in the file name

The missing data value is 1.0 x 1037, indicating data is not available at the corresponding time for the given variable. The first ISFS measurements were recorded on Nov 10, 2010. Therefore, values for all time-series variables will be filled with 1x1037 for the initial portion of pcaps30m_20101101.nc.

The variables in the NetCDF files are defined by one or more of the following dimensions:

Dimension name size description
time 1440 or 1448 number of 1/2 hour periods in the month
station 7 index for each of the 7 ISFS stations


The variables in the NetCDF files are:

Variable name units dimensions description
base_time seconds none (scalar) POSIX time, non-leap seconds since 1970-01-01 00:00:00 00:00 UTC of 0:00 UTC of the first day of the month
time seconds time middle of sampling period, in seconds since base_time.
LE W/m2 time,station latent heat flux, positive is upward
H W/m2 time,station sensible heat flux, positive is upward
u_  (*) m/s time,station u*, friction velocity
Rsum W/m2 time,station total radiation, positive downward, from pyranometer and pyrgeometer measurements at 2 meters
Gsfc W/m2 time,station surface heat flux, positive is upward
Gsfc_aux W/m2 time,station surface heat flux at auxiliary soil measurement sites of stations 1, 5 and 6
latitude degrees-north station  
longitude degrees-east station  
altitude m station Approximate station altitude, above sea level
sonicHeight m station Approximate height above ground of sonic anemometer and fast hygrometer eddy correlation measurements


* By convention, NetCDF variable names are limited to A-Z, a-z, 0-9 and underscore characters. The usual name for the friction velocity is "u*", which is converted to "u_" as a NetCDF variable. See the "short_name" attribute for each variable, which does not have a restricted character set.