Data / Science Data Products / VAPs

QCECOR

Quality Controlled Eddy Correlation Flux Measurement

Baseline VAP

The QCECOR VAP is designed to improve the surface turbulence fluxes from eddy correlation flux (ECOR) measurements.

Two variables, surface latent heat flux and sensible heat flux, are included in earlier versions of QCECOR. An enhanced version of QCECOR now includes carbon dioxide fluxes (one of the primary ECOR measurements) in addition to the surface latent heat flux and sensible heat flux.

Moreover, the usage of the co-located surface energy balance system (SEBS) wetness quality control (QC) flag in earlier versions of QCECOR resulted in the removal of too many nonsuspicious data points, especially during night. Therefore, in the enhanced version of QCECOR, wetness information from SEBS data is included, but it is not applied for any QC procedures.

QCECOR data are provided as daily files in netCDF format with a time resolution of 30 minutes.

Users are recommended to use the corrected surface turbulent fluxes of sensible heat, latent heat, and carbon dioxide from QCECOR instead of ECOR data when available.

Besides the ECOR, the energy balance Bowen ratio (EBBR) system is installed in the broad ARM Southern Great Plains (SGP) region to estimate vertical fluxes of sensible and latent heat at the surface. At the SGP Central Facility, the two instruments are within a few hundred meters apart. However, the turbulence fluxes measured from the ECOR and EBBR are found to have significant differences, mainly due to the various surface vegetation types the instruments are representing. Users need to be careful about the surface type representation when using the turbulent flux measurements from the ECOR and EBBR. More information about the comparison of the ECOR and EBBR at the SGP can be found in Tang et al. (2019).

More information on QCECOR is available in the technical report.

Reference: Tang S, S Xie, M Zhang, Q Tang, Y Zhang, S Klein, D Cook, and R Sullivan. 2019. “Differences in Eddy‐Correlation and Energy‐Balance Surface Turbulent Heat Flux Measurements and Their Impacts on the Large‐Scale Forcing Fields at the ARM SGP Site.” Journal of Geophysical Research: Atmospheres, 124(6), https://doi.org/10.1029/2018JD029689.