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NMEG flux processing workflow (MATLAB version)

These are the basic steps/scripts for generating 30-minute averages and calculating fluxes from our 10hz data at each site.

  1. UNM_process_10hz_main.m is the primary script for processing 10hz data in TOB1 files.

    • Generates list of daily TOB1 files (in 30 day chunks by default) for processing by process_TOB1_chunk.m
    • Concatenates the resulting data.
    • Default sonic rotation is 3d (3-axis or double rotation)

  2. process_TOB1_chunk.m

    • Read TOB1 files in each 30 day chunk, break into 30min blocks
    • Send each 30min block to UNM_30min_TS_averager.m and then concatenate resulting data.

  3. UNM_30min_TS_averager.m

    • Calculates average values for 30 minute blocks of 10hz data, including calculated fluxes. In the process of doing this it calls:
      • UNM_dry_air_conversions.m which calculates Tdry, despikes pressure data, and does other conversions.
      • UNM_csat3.m which despikes u, v, w wind data, adjusts THETA using the site-specific sonic orientation, and calculates 30min averages of wind data.
      • UNM_coordrot.m which provides the coordinate rotation for flux calculations. Default is 3d, which is not ideal, but there is a method for planar rotation here too.
      • UNM_flux_031010 which calculates the covariance matrices for wind and scalar data, performs raw flux calculations and corrections (see sub-bullets). This code can loop using different lag times, but the default is no lag. It returns a 30 minute flux observation. The corrections called are:
        • UNM_WPLMassman.m which calls UNM_Massman.m. These two scripts perform the high frequency loss correction (Massman method), and the Webb, Pearman, Leuning density corrections (in that order).
        • Linear detrending of variables has in the past occurred in the UNM_Massman.m code, but it appears that this is no longer the case.
        • The WPL correction may actually be done at the very end of this script (needs to be checked) and that becomes the 'FC_corr/raw_massman_ourwpl.m' flux.
    • The UNM_30min_TS_averager.m then puts these together and returns met and flux averages for the 30 minute period.

The steps above create a dataset that is merged into the SITE_fluxall.dat file. There are additional steps that occur in the RemoveBadData.m script. These are:

  1. Burba correction (T below 0 C)
  2. Lots of hi/low filtering, flux removal based on precip, behind tower wind, nighttime negative fluxes, low ustar values, outlier removal,