NACP Site: Tower Meteorology, Flux Observations with Uncertainty, and Ancillary Data

This data set contains meteorological, carbon cycle flux, phenology, and ancillary data measured at 47 eddy covariance flux tower sites across North America. The data were used by North American Carbon Program (NACP) Site-Level Synthesis as model driver data and for assessing how well 24 Terrestrial Biosphere Models simulated carbon processes across vegetation types and environmental conditions. The meteorology data include eight variables: air temperature (K), specific humidity (kg/kg), wind speed (m/s), precipitation (kg/m2/s), surface pressure (Pa), surface incident shortwave radiation (W/m2), surface incident longwave radiation (W/m2), and CO2 concentration (ppm). Gap-filled data were used by modeling teams as input model driver data. Measured fluxes of net ecosystem exchange (NEE) and derived gross primary productivity (GPP) and respiration (R) and respective calculated uncertainty estimates are provided for each tower site at the native time resolution of the observations (30 or 60-minute) as well as the diurnal, seasonal, and annual time scales. The data were gap-filled following a standard protocol. Components of uncertainty include uncertainties resulting from turbulence, gap-filling, flux partitioning, and u threshold determination. Flux observations and uncertainty data were used to assess how well models simulated carbon processes. Remotely sensed NDVI, LAI, and fPAR phenology data were derived from the GIMMS version g NDVI data set for each flux tower site. Phenology data were used by some modeling teams as input model driver data. *Ancillary data and information describe tower location and physical characteristics, disturbance history, and biological and ecological attributes of the vegetation, litter, and soil. These ancillary data were used by modeling teams as input model driver data.

The data files are in both ASCII text and NetCDF formats (ALMA standard).

The compilation of these data was facilitated by the NACP Modeling and Synthesis Thematic Data Center (MAST-DC).

Data and Resources

Additional Info

Field	Value
Maintainer	Earthdata Forum
Last Updated	June 23, 2026, 01:17 (UTC)
Created	April 1, 2025, 17:55 (UTC)
accessLevel	public
bureauCode	{026:00}
catalog_conformsTo	https://project-open-data.cio.gov/v1.1/schema
harvest_object_id	a2fc8ca0-f106-47b2-8a9a-a42296437675
harvest_source_id	b99e41c6-fe79-4c19-bbc3-9b6c8111bfac
harvest_source_title	Science Discovery Engine
identifier	10.3334/ORNLDAAC/1178
license	https://www.usa.gov/government-works
modified	2026-06-15T22:16:01Z
programCode	{026:000}
publisher	ORNL_DAAC
resource-type	Dataset
source_datajson_identifier	true
source_hash	fbe787a2a151dd0991c92d103c03cefc0b0c85e6dacc15d66371409af1e70113
source_schema_version	1.1
spatial	["CARTESIAN", [{"WestBoundingCoordinate": -157.409, "NorthBoundingCoordinate": 71.3225, "EastBoundingCoordinate": -68.7403, "SouthBoundingCoordinate": 33.3739}]]
temporal	1991-01-01/2007-12-31
theme	{"Earth Science"}