EC Raw Binary Format (CH-CHA)

See here for more info about the EC raw binary format.



  • * … The star marks significant changes in the setup that required a new time period
  • Binaries From … The first valid file that contains the first data for the respective year.
  • Binaries To … The last valid file that contains the last data for the respective year.
  • FRMT … The format settings that were used. FRMT files contain information about the sequence of incoming data, e.g. first the SA, then GA1, then GA2. Generally, the FRMT files contain correct information about these data sequences, but not necessarily about processing settings because the settings are different depending on the use case (e.g. preliminary fluxes use settings that speed up processing time). For time periods with the same processing settings, check GA1S, GA2S etc.
  • GA … Gas analyzer. If the GA is given in brackets it means that the GA was removed from the site but its data (empty) is still part of the data stream / raw data. In this case the raw data contains mostly empty columns (status and data size of the GA is still recorded). GA in brackets means that the instrument is still part of the data stream but data are empty, e.g. when it was removed from the site.
  • GA1S, GA2S … Gas anaylzer setup: A more accurate setup info than FRMT, time periods with the same ID have the identical processing settings, e.g. the same sensor separation settings. Time periods with the same ID can be calculated together (data can be pooled) for e.g. final flux calculations. However, sometimes data for GA1 of different time periods can be pooled, but not data for GA2, therefore these IDs are given separately for each gas analyzer. Check if the setup changes allows for data pooling of a specific GA.
  • GA1 Sep, GA2 Sep … Northward N, Eastward E and Vertical V separation of the GA inlet in relation to the SA center, given in mm (Note: EddyPro needs distances in cm), for more info see here. Also given is the tube length TL in mm if the GA is a closed-path analyzer.
  • R350 … Gill R3-50 sonic anemometer
  • RGA75 … LI-COR 7500 open path infrared gas analyzer
  • SA … Sonic anemometer
  • SA Ori … The direction in which the spar where the SA is mounted points.
  • Year … Given with an underscore, whereby the underscore denotes a change in the data format. For example, in 2015_2 the QCL was added to the data file, but the QCL was not installed in 2015_1.


Setup since 2005

wdt_ID Year FRMT GA1S GA2S Binaries From Binaries To SA GA 1 GA 2 SA Ori GA1 Sep GA2 Sep Notes
Year FRMT GA1S GA2S Binaries From Binaries To SA GA 1 GA 2 SA Ori GA1 Sep GA2 Sep Notes


  • For QCL the version and variant according to Table 2 in WE’s sonicread.pdf is given.
  • A new naming convention for data blocks is currently (Aug 2020) in preparation: Data Blocks.

(1) 7° north offset, measured for the north spar in 2016. Assumed to be the same for all years.

(2) Modified data acquisition to also record QCL temperature and pressure. Now there are 5 QCL variables that are detected (there were 3 in previous versions).

(3) For this short time the QCL was run with the CH-DAV QCL setup. For more info see here: ch-cha-2016-data-issues.pdf

(4) QCL format: see GIN entry 26 Nov 2018. QCL was re-installed at site on 16 Nov 2018, data logging started on 26 Nov 2018. This period is a special case:

  • Var1 is CH4 (ppb), but 10x too large (for total amplification of 10000).
  • Var2 is H2O, but not in full resolution because only 1-2 digits after the comma, needs multiplication w/ 10000? or according to WE w/1000? to give proper ppb values.
  • Var3 is N2O, but 10000x too large I think it is 10x too large, but the total amplification is 10000.
  • Var4 we do not want, please ignore.
  • Var5 is cell temperature, but 10x too large (total amplification of 10000).
  • Cell pressure is missing in these files.

In summary, to get proper values, the 4-Byte values in the raw binary file have to be multiplied like this: CH4 x 0.0001, H2O x 1000, N2O x 0.0001, cell temperature x 0.0001. Name of data block in python script FCT: data_block_qcl_ver1_var6_b_ch_cha_2018_2. Gains are applied during conversion from binary to ASCII csv files, i.e. there are ppb values in the converted files.

The format is basically the same as FRMT-E, but in the EddyPro settings in Instruments > Instrument ID the data block qcl_v1v6b_ch-cha_2018_2 has to be used to account for the different gains.

(5) The separation given for the QCL seems more or less correct, see this image.

(6) QCL is defective and was removed from the site on 11 Apr 2018 (factory repair). The QCL is still part of the raw data, but all its data are empty.

(7) TODO The multiplier of 1000 got set back to 1 so that the QCL H2O concentrations could be saved correctly. See GIN entries from 13 May 2020 and 15 May 2020. Direct link to info text file.

(8) Calibration gas issue: Due to the IRGA75 replacement of in 15 Mar 2017, only a short time period of approx. 2 months is affected by the wrong calibration gas. Affected time period: all IRGA75 CO2 concentrations between 2017011114.C57 and 2017031507.C00. For more info see here.

(9) After checking the raw data plots, the QCL seems defective after 29 Mar 2018 approx. since 15:34h, the  (most QCL sginals stop with record 184 706 instead of 431 990 in the 6-hour raw data file). Nearly half of the file 2018032913.C00 still contains usable data.

(10) According to GIN, QCL H2O has now a different multiplier but data look like FRMT D without multiplier. QCL format: see GIN entry 7 Dec 2018. Basically the same format as D, but the H2O signal of the QCL is multiplied by factor 1000 in the raw data file (to take into account more digits that are output by the QCL).After checks it looks like this is indeed format D.

(11) See GIN entry from 13 May 2020: Instead of the H2O concentration the ambient CH4 concentration got recorded.

(12) QCL removed from site 5 Feb 2020 10:50h.

(13) IRGA75 was calibrated on 30 Apr 2019 with correct calibration gas.

(14) I assume that the GA1 separation is the same as was later measured in Feb 2019. Here during this time period in 2018, the QCL (GA2) inlet was moved which means there was a setup change at the site. I assume that the setup change was also the case for GA1. It was not possible to find out more details from the fieldbook.


EddyPro Settings

.eddypro and .metadata files for flux calculations. These files contain info about the instrument setup, i.e. what instruments are installed and in which sequence. Processing options might need to be adjusted as needed.

File size < 20 KB.