Modified

27 October 2026

Flux Post-processing Chain

The fluxes are processed along the Swiss FluxNet flux processing chain. EddyPro calculates the fluxes (Levels 0 and 1); the Python library diive runs the post-processing (Levels 2 to 4).

NoteFP2026.1 and IRGA75

FP2026.1 contains the fluxes of the enclosed-path LI-7200 (IRGA72), 2016 to September 2026, up to Level 4.1. The fluxes of the open-path LI-7500 (IRGA75, 2004 to 2017 and 2019) pass through the additional self-heating correction of Level 1.1. They are in progress for FP2026.2 and are not part of FP2026.1.

Flowchart

flowchart TB
    ecbin["EC raw data, binary"]
    bico["bico"]
    eccsv["EC raw data, ASCII"]
    met["meteo data"]
    EP["EddyPro, run with fluxrun"]
    L0F["L0: preliminary fluxes"]
    L1F["L1: final fluxes"]
    L11F["L1.1: self-heating correction (IRGA75 only, FP2026.2)"]

    subgraph diive_chain["diive post-processing chain"]
        L2QCF["L2: quality flags"]
        L31F["L3.1: storage term (NEE only)"]
        L32QCF["L3.2: outlier flags"]
        L33QCF["L3.3: USTAR flags (NEE only)"]
        QCF["overall quality flag QCF"]
        L41F["L4.1: gap-filling (XGBoost, MDS for comparison)"]
        L42F["L4.2: partitioning of NEE (not in FP2026.1)"]
    end

    ecbin --> bico --> eccsv --> EP
    EP --> L0F
    L0F -- "informs settings" --> L1F
    met -- "biomet input" --> L1F
    EP --> L1F
    L1F --> L11F
    L1F --> L2QCF
    L11F --> L2QCF
    L2QCF --> L31F --> L32QCF --> L33QCF --> QCF --> L41F --> L42F

    classDef orange fill:#FFE0B2,stroke:#E65100,stroke-width:2px,color:#E65100
    class L2QCF,L32QCF,L33QCF,QCF orange

    classDef green fill:#DCEDC8,stroke:#33691E,stroke-width:2px,color:#33691E
    class L0F,L1F,L11F,L31F,L41F,L42F green

    classDef blue fill:#E1F5FE,stroke:#01579B,stroke-width:2px,color:#01579B
    class bico,EP blue

    classDef white fill:#FFFFFF,stroke:#000000,stroke-width:2px,color:#000000
    class diive_chain white

Processing steps

Table 1: The processing steps and whether their output is part of FP2026.1.
Step What it does In FP2026.1
Raw data 20 Hz raw data, converted from binary to ASCII not included
Level 0 Preliminary flux calculation, to check the setup and choose the lag windows not included
Level 1 Final flux calculation with EddyPro, one run per setup period yes
Level 1.1 Self-heating correction of the open-path IRGA75 no, FP2026.2
Level 2 Quality flags from the EddyPro output yes
Level 3.1 Storage term added to FC, giving NEE yes
Level 3.2 Outlier flags yes
Level 3.3 USTAR flags at three constant thresholds (NEE only) yes
QCF Overall quality flag, combining the flags of all levels yes
Level 4.1 Gap-filling with XGBoost; MDS for comparison yes
Level 4.2 Partitioning of NEE into GPP and RECO no

LE (with ET) and H pass through the same levels without a storage term and without a USTAR filter, as in Pastorello et al. (2020). H uses only the quality flags of the sonic anemometer.

Notebooks of the IRGA72 chain

Table 2: Notebooks of the post-processing chain for IRGA72.
Notebook Content
00_FPPC_IRGA72_INPUT_2016-2026.09 Joins the Level-1 fluxes with the meteo data
01_FPPC_IRGA72_NEE_2016-2026.09 NEE: Levels 2 to 4.1 and the uncertainty
11_FPPC_IRGA72_LE_2016-2026.09 LE and ET: Levels 2 to 4.1
15_FPPC_IRGA72_H_2016-2026.09 H: Levels 2 to 4.1
99_FPPC_IRGA72_MERGED_2016-2026.09 Merges the output of the three flux notebooks
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