Abstract

Past efforts to synthesize and quantify the magnitude and change in carbon dioxide (CO2) fluxes in terrestrial ecosystems across the rapidly warming Arctic-Boreal Zone (ABZ) have provided valuable information, but were limited in their geographical and temporal coverage. Furthermore, these efforts have been based on data aggregated over varying time periods, often with only minimal site ancillary data, thus limiting their potential to be used in large-scale carbon budget assessments. To bridge these gaps, we developed a standardized monthly database of Arctic-Boreal CO2 fluxes (ABCflux) that aggregates in-situ measurements of terrestrial net ecosystem CO2 exchange and its derived partitioned component fluxes: gross primary productivity and ecosystem respiration. The data span from 1989 to 2020 with over 70 supporting variables that describe key site conditions (e.g., vegetation and disturbance type), micrometeorological and environmental measurements (e.g., air and soil temperatures) and flux measurement techniques. Here, we describe these variables, the spatial and temporal distribution of observations, the main strengths and limitations of the database, and the potential research opportunities it enables. In total, ABCflux includes 244 sites and 6309 monthly observations; 136 sites and 2217 monthly observations represent tundra, and 108 sites and 4092 observations represent the boreal biome. The database includes fluxes estimated with chamber (19 % of the monthly observations), snow diffusion (3 %) and eddy covariance (78 %) techniques. The largest number of observations were collected during the climatological summer (June–August; 32 %), and fewer observations were available for autumn (September–October; 25 %), winter (December–February; 18 %), and spring (March–May; 25 %). ABCflux can be used in a wide array of empirical, remote sensing and modeling studies to improve understanding of the regional and temporal variability in CO2 fluxes, and to better estimate the terrestrial ABZ CO2 budget. ABCflux is openly and freely available online (https://doi.org/10.3334/ORNLDAAC/1934, Virkkala et al., 2021a).

Highlights

  • The Arctic–boreal zone (ABZ), comprising the northern tundra and boreal biomes, stores approximately half the global soil organic carbon pool (Hugelius et al, 2014; Tarnocai et al, 2009; Mishra et al, 2021)

  • This paper provides a general description of the Arctic–boreal CO2 fluxes (ABCflux) database by characterizing the data sources and database structure (Sect. 2), as well as describing the characteristics of the database

  • ABCflux focuses on the area covered by the northern tundra and boreal biomes (> 45◦ N), as characterized in Dinerstein et al (2017), Fig. 2, and compiles in situ measured terrestrial ecosystem-level CO2 fluxes aggregated to monthly time periods

Read more

Summary

Introduction

The Arctic–boreal zone (ABZ), comprising the northern tundra and boreal biomes, stores approximately half the global soil organic carbon pool (Hugelius et al, 2014; Tarnocai et al, 2009; Mishra et al, 2021). But not all, of the ABZ eddy covariance sites are a part of broader networks, such as the global FLUXNET and regional AmeriFlux, Integrated Carbon Observation System (ICOS) and the European Fluxes Database Cluster (EuroFlux), where data are standardized and openly available (Paris et al, 2012; Novick et al, 2018; Pastorello et al, 2020). These networks primarily include flux and meteorological data but do not often include other environmental descriptions such as soil carbon stocks, dominant plant species, or the disturbance history of a given site (but see, for example, Biological, Ancillary, Disturbance, and Metadata data in Ameriflux), which are important for understanding the controls on CO2 fluxes. We describe the main strengths, limitations, and opportunities of this database (Sect. 4) and its potential utility for future studies aiming to understand terrestrial ABZ CO2 fluxes

Data and methods
Literature search
Flux repositories
Permafrost Carbon Network data solicitation
Partitioning approaches at eddy covariance flux sites
Data quality screening
Database structure and columns
Database visualization
General characteristics of the database
Coverage of ancillary data
Coverage and distribution of flux data
Comparing fluxes estimated with different techniques
Uncertainties in eddy covariance flux partitioning
Representativeness and completeness of the data
Data use guidelines
Findings
Conclusions
Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call