High-Frequency Eddy Covariance Measurements of CO2 Fluxes in a Mountain Watershed: A Comprehensive Dataset for Understanding Carbon Exchange Dynamics in Forest Ecosystems

The eddy covariance (EC) technique is employed to measure the exchange of gases, such as carbon dioxide (CO2), between the atmosphere and an ecosystem. This data description provides an overview of the eddy covariance measurements (CPEC310 and AP200 systems).The measurements were carried out using three flux towers located within a mountain watershed. The towers were strategically positioned to capture the variations in CO2 fluxes above forest canopies in complex terrains. The EC method relies on high-frequency measurements of vertical wind velocity and the corresponding fluctuations in CO2 concentration.The data collection period spanned from Jan 01, 2020 to Dec 31, 2021, which was carefully selected to capture diurnal and seasonal variations in the CO2 fluxes. The measurements were performed at a high temporal resolution, typically at intervals of 30 minutes. This high-frequency sampling allows for accurate estimation of the fluxes and their variability.To ensure data quality, the instruments used for the measurements were carefully calibrated and maintained. The vertical wind velocity was measured using three-dimensional sonic anemometers, while the CO2 concentration was measured using fast-response infrared gas analyzers. These instruments are well-established and widely used in eddy covariance studies.The collected data includes time series of friction velocity, CO2 concentration fluctuations, and the corresponding fluxes. These variables provide valuable information on the exchange of CO2 between the ecosystem and the atmosphere. Additionally, ancillary measurements such as terrain complexity index, wind speed, and sensible heat fluxes may have been recorded concurrently to facilitate further analysis and interpretation.The dataset covers a range of meteorological conditions, including different seasons and weather patterns. Spatial variations across the study area are also captured through the multiple flux tower locations. This comprehensive dataset enables detailed analysis of the CO2 flux dynamics, including the impacts of terrain complexity, diurnal cycles, and seasonal variations.In summary, the eddy covariance measurements conducted in this study provide a valuable dataset of high-frequency CO2 fluxes and related variables. This dataset enables investigations into the temporal and spatial dynamics of CO2 exchange in forest ecosystems, contributing to a better understanding of carbon cycling and ecosystem functioning.