DOI: 10.48443/j9pt-m241
title: Bundled data products - eddy covariance (DP4.00200.001)
title: RELEASE-2024

description: Net surface-atmosphere exchange, or “flux” quantifies how much heat, water (H2O) and carbon dioxide (CO2) are transferred between an ecosystem and the atmosphere. Fluxes are useful in a variety scientific applications, including to study ecosystem processes, to interpret and calibrate satellite observations of the earth system, and to constrain ecosystem and earth system models. One of the most direct approaches to observe the net surface-atmosphere exchange is the in-situ [eddy-covariance method](https://youtu.be/CR4Anc8Mkas). Calculation of the net surface-atmosphere exchange involves the estimation of at least two major terms (assuming horizontally homogenous surface conditions): the turbulent flux and the storage flux. In addition, stable isotope measurements of CO2 and H2O within and above the ecosystem canopy can support the subsequent partitioning of the net surface-atmosphere exchange into ecosystem constituent fluxes. For example, partitioning CO2 into photosynthesis and respiration, or evaporation and transpiration in the case of H2O.

For data product and algorithm details please see [NEON.DOC.004571](http://data.neonscience.org/documents); in short: this data product bundle contains derived eddy-covariance data products and associated metadata in HDF5 format. Each file contains metadata about the file structure, table formats, and attributes. For more information on using HDF5 files, please visit The HDF Group website at https://www.hdfgroup.org/. Data, quality flags and metrics (qfqm), and uncertainty metrics (ucrt) are currently provided in folders using the following naming convention within the HDF5 file structure: `data_product_level`/`type_of_data_available`/`data_product_abbreviation` (e.g., “dp01/data/soni”). Empty folders within the file structure are being incrementally filled in future publications. The data products embedded in this bundle currently include the following:

| Data Product | Type of data available | Abbreviation | Temporal Resolution |
| ------------ | ---------------------- | ------------ | ------------------- |
| DP1.00002 Single aspirated air temperature | data, qfqm, ucrt | tempAirLvl | 1-min, 30-min |
| DP1.00003 Triple aspirated air temperature | data, qfqm, ucrt | tempAirTop | 1-min, 30-min |
| DP1.00007 3D wind speed, direction and sonic temperature | data, qfqm, ucrt | soni | 1-min, 30-min |
| DP1.00010 3D wind attitude and motion reference | data, qfqm, ucrt | amrs | 1-min, 30-min |
| DP1.00034 CO2 concentration - turbulent | data, qfqm, ucrt | co2Turb | 1-min, 30-min |
| DP1.00035 H2O concentration - turbulent | data, qfqm, ucrt | h2oTurb | 1-min, 30-min |
| DP1.00036 Atmospheric CO2 isotopes | data, qfqm, ucrt | isoCo2 | 9-min, 30-min |
| DP1.00037 Atmospheric H2O isotopes | data, qfqm, ucrt | isoH2o | 9-min, 30-min |
| DP1.00099 CO2 concentration - storage | data, qfqm, ucrt | co2Stor | 2-min, 30-min |
| DP1.00100 H2O concentration - storage | data, qfqm, ucrt | h2oStor | 2-min, 30-min |
| DP2.00008 CO2 concentration rate of change | data, qfqm | co2Stor | 30-min |
| DP2.00009 H2O concentration rate of change | data, qfqm | h2oStor | 30-min |
| DP2.00024 Temperature rate of change | data, qfqm | tempStor | 30-min |
| DP3.00008 Temperature rate of change profile | data, qfqm | tempStor | 30-min |
| DP3.00009 CO2 concentration rate of change profile | data, qfqm | co2Stor | 30-min |
| DP3.00010 H2O concentration rate of change profile | data, qfqm | h2oStor | 30-min |
| DP4.00002 Sensible heat flux | data, qfqm | fluxTemp | 30-min |
| DP4.00007 Momentum flux | data, qfqm | fluxMome | 30-min |
| DP4.00067 Carbon dioxide flux | data, qfqm | fluxCo2 | 30-min |
| DP4.00137 Latent heat flux | data, qfqm | fluxH2o | 30-min |
| DP4.00201 Flux footprint characteristics | data, qfqm | foot | 30-min |

Latency:
Data collected in any given month are published during the second full week of the following month.
description: All terrestrial NEON sites are equipped with a tower and sensors that collect turbulent flux measurements at the tower top. The CSAT-3 sonic anemometer (Campbell Scientific Inc., Logan, Utah, USA) records 3-dimensional wind speed and wind direction data at 20 Hz. The attitude and motion reference system (AMRS, Xsens North America Inc., model MTI-300-2A5G4; Culver City, California, USA) tracks the motion of the CSAT-3 sonic anemometer and records pitch, roll and yaw data at 40 Hz. The LI-7200 and LI-7200RS gas analyzers (Li-Cor Inc., Lincoln, Nebraska, USA) records CO2 and H2O concentration at 20 Hz. These dp00 raw data are used to generate 1-min and 30-min dp01 descriptive statistics data products, as well as 30-min dp04 turbulent flux data products.

The storage flux system consists of a suite of sensors that record temperature, CO2 and H2O along the tower vertical profile. The air temperature profile is measured at 1 Hz with aspirated temperature sensors (MetOne Instruments, Inc., model 076B-7388; Grant Pass, Oregon, USA). In addition, air samples from all vertical measurement levels on the tower are drawn and delivered to a gas analyzer (Li-Cor, Inc., model LI-840A and LI-850; Lincoln, Nebraska, USA) in the instrument hut for analysis. The LI840A and LI850 gas analyzers record the CO2 and H2O concentration at 1 Hz. These data are used to generate 2-min and 30-min dp01 descriptive statistics data products, which are used to further produce 30-min dp02 temporally interpolated data products, dp03 spatially interpolated data products, and derived dp04 storage flux data products.

Sensors for stable isotopic measurements are located inside the instrument hut. Air samples along the tower vertical profile are drawn and delivered to the sensors for analysis. The PICARRO G2131-i CO2 isotopic analyzer records the CO2 concentration and delta 13C at ~1 Hz; the PICARRO L2130-i H2O isotopic analyzer records the H2O concentration and delta 18O and 2H at ~1 Hz. These data are used to generate 9-min and 30-min dp01 descriptive statistics data products.

For command, control and configuration details please see [NEON.DOC.000456](http://data.neonscience.org/documents). Instrumentation: LI-COR - LI7200 gas analyzer; Campbell Scientific CSAT-3 3-D Sonic Anemometer; Xsens North America Inc. MTI-300-2A5G4 Attitude Heading Reference System; LI-COR - LI840A; PICARRO - G2131-i isotopic CO2 analyzer; PICARRO - l2130-i isotopic H2O analyzer