Variables¶

Flux files name every column with a code such as TA_F_1_1_1 or GPP_NT_VUT_REF. Two tools turn those codes into something you can use. Neither needs an account, and both work over stdio and HTTP. Inputs and result fields are in the Tool reference.

Two kinds of name¶

BASE names (AmeriFlux BASE, the FP Standard³) are a base name and qualifiers:

<BASE NAME>[_PI][_QC][_F][_IU][_H_V_R | _H_V_A | _#][_SD | _N]

FLUXNET names (FLUXNET2015 FULLSET and SUBSET⁴, and the AmeriFlux FLUXNET product made with ONEFlux v1.3) add processing tokens: _F_MDS (gap-filled with MDS), _ERA (downscaled from reanalysis), _VUT/_CUT (USTAR threshold varies by year or is constant), _REF and the percentiles _05 … _95, _NT/_DT/_SR (partitioning method), _RANDUNC, _CORR, _DAY/_NIGHT, _QC.

Units and QC change with resolution¶

FLUXNET files come at HH (half-hourly or hourly), DD, WW, MM and YY, and one name means different units at each¹:

Every FLUXNET result carries unitsByResolution; pass resolution to get one unit and the QC meaning at that resolution. Negative NEE and FC are uptake; GPP and RECO are positive.

amf_search_variables¶

Words match names, descriptions and units (prefixes count). Choose a dictionary:

category filters by FP type (GASES, MET_SOIL) or FLUXNET section (PARTITIONING, SUNDOWN); resolution keeps the FLUXNET names produced at it.

{"tool": "amf_search_variables", "arguments": {"query": "soil temperature"}}
{"tool": "amf_search_variables", "arguments": {"query": "GPP", "dictionary": "fluxnet_subset", "resolution": "DD"}}

Dictionary names with XX or # stand for many columns: NEE_VUT_XX is NEE_VUT_05 to NEE_VUT_95, and TS_F_MDS_# is TS_F_MDS_1 (shallowest), TS_F_MDS_2, …

amf_describe_variables¶

Up to 20 names per call. Each result gives the base name and its FP definition, every qualifier or token with its meaning, the position, the units, the FLUXNET definition (with the dictionary key: NEE_VUT_05 is NEE_VUT_XX), a sign convention where one applies, and didYouMean for names it does not recognize. A name valid in both grammars (TA_F) gets both readings, with a note.

With site, each name also gets:

• whether the site's BASE data include the base name (from the catalog);
• sensor heights and instruments from AmeriFlux's measurement-height file;
• yearly coverage per column from amerifluxr's snapshot, marked with its date (2025-10-20 as of this writing; it lags the current BASE release).

{"tool": "amf_describe_variables", "arguments": {"names": ["GPP_NT_VUT_REF", "TA_F_MDS_QC"], "resolution": "DD"}}
{"tool": "amf_describe_variables", "arguments": {"names": ["TA", "SWC_1_1_1"], "site": "US-Ha1"}}

The first call with site downloads the measurement-height file (about 2.3 MB) and the coverage snapshot (about 6.5 MB). Both are cached: heights for 24 hours, coverage for 7 days.

Sources and resources¶

The FLUXNET dictionary is built by scripts/build_variable_dictionaries.py from the FLUXNET2015 webdoc dictionaries and ONEFlux's var_info_definitions files. The micro sign is restored where ONEFlux stores it as a replacement character².