White Paper: Eddy Covariance Measurements in Urban Environments

July 2021: written by Sébastien Biraud (Lawrence Berkeley National Laboratory), Jiquan Chen (Michigan State University), Andreas Christen (University of Freiburg, Germany), Ken Davis (Penn State University), John Lin (The University of Utah), Joe McFadden (University California Santa Barbara), Chip Miller (NASA Jet Propulsion Lab), Eiko Nemitz (UK Centre for Ecology & Hydrology), Gunnar Schade (Texas A&M University), Stavros Stagakis (University of Basel, Switzerland), Jocelyn Turnbull (GNS Science and University of Colorado), Roland Vogt (University of Basel, Switzerland).

This white paper was prepared by an AmeriFlux ad hoc committee on Urban Fluxes, in response to a request by the DOE Program Manager for the AmeriFlux Management Project. It provides a brief summary of the committee’s assessment of the challenges and opportunities for eddy covariance (EC) flux measurements in urban environments, including built and terrestrial areas, and gives technical recommendations.

White Paper: Understanding land-atmosphere interactions through tower-based flux and continuous atmospheric boundary layer measurements

June 2020: Written by Manuel Helbig, Tobias Gerken, Eric Beamesderfer, Dennis D Baldocchi, Tirtha Banerjee, Sebastien C. Biraud, Nathaniel A. Brunsell, Sean P. Burns, Brian Butterworth, W. Stephen Chan, Ankur R. Desai, Jose D. Fuentes, David Y. Hollinger, Natascha Kljun, Matthias Mauder, Kimberley A. Novick, John M. Perkins, Camilo Rey-Sanchez, Russel L. Scott, Bijan Seyednasrollah, Paul C Stoy, Ryan C. Sullivan, Jordi Vilà-Guerau de Arellano, Sonia Wharton, Chuixiang Yi, Andrew D. Richardson

Target audience: AmeriFlux community, AmeriFlux Science Steering Committee & Department of Energy (DOE) program managers [ARM/ASR (atmosphere), TES(surface), and SBR (subsurface)]

Problem Statement: The atmospheric boundary layer mediates the exchange of energy and matter between the land surface and the free troposphere integratinga range of physical, chemical, and biological processes. However, continuous atmospheric boundary layer observations at AmeriFlux sites are still scarce. How can adding measurementsof the atmospheric boundary layer enhance the scientific value of the AmeriFlux network?

Research Opportunities: We highlight four key opportunities to integrate tower-based flux measurements with continuous, long-term atmospheric boundary layer measurements: (1) to interpret surface flux and atmospheric boundary layer exchange dynamics at flux tower sites,(2) to support regional-scale modeling and upscaling of surface fluxes to continental scales,(3) to validate land-atmosphere coupling in Earth system models,and (4) to support flux footprint modelling, the interpretation of surface fluxes in heterogeneous terrain, and quality control of eddy covariance flux measurements.

Recommended Actions: Adding a suite of atmospheric boundary layer measurements to eddy covariance flux tower sites would allow the Earth sciencecommunity to address new emerging research questions, to betterinterpret ongoing flux tower measurements, and would present novel opportunities for collaboration between AmeriFlux scientistsandatmospheric and remote sensing scientists. We therefore recommend that (1) a set of instrumentation for continuous atmospheric boundary layer observations be added to a subset of AmeriFlux sites spanning a range of ecosystem types and climate zones,that (2) funding agencies (e.g., Department of Energy, NASA) solicit research on land-atmosphere processes where the benefits of fully integrated atmospheric boundary layer observations can add value to key scientific questions, and that (3) the AmeriFlux Management Project acquires loaner instrumentation for atmospheric boundary layer observations for use in experiments and short-term duration campaigns.

White Paper: Globally interoperable eddy-covariance data products through affiliating NEON sites with AmeriFlux and FLUXNET

November 2016: Written by Stefan Metzger (Battelle Ecology, National Ecological Observatory Network Project, Boulder, CO, USA), Deborah Agarwal (Lawrence Berkeley National Laboratory, AmeriFlux Management Project, Berkeley, CA, USA), Sebastien Biraud (Lawrence Berkeley National Laboratory, AmeriFlux Management Project, Berkeley, CA, USA), David Durden (Battelle Ecology, National Ecological Observatory Network Project, Boulder, CO, USA), Hongyan Luo (Battelle Ecology, National Ecological Observatory Network Project, Boulder, CO, USA), Dario Papale (University of Tuscia, Integrated Carbon Observing System – Ecosystem Thematic Center, Viterbo, Italy), Gilberto Pastorello (Lawrence Berkeley National Laboratory, AmeriFlux Management Project, Berkeley, CA, USA), Cove Sturtevant (Battelle Ecology, National Ecological Observatory Network Project, Boulder, CO, USA), Margaret S. Torn (Lawrence Berkeley National Laboratory, AmeriFlux Management Project, Berkeley, CA, USA).

The 2016 AmeriFlux-NEON White Paper “Globally interoperable eddy-covariance data products through affiliating NEON sites with AmeriFlux and FLUXNET” resulted from jointly led breakout sessions at the 2016 AmeriFlux Principal Investigator Meeting in Golden, CO. The White Paper established the foundation and goals of the now active collaboration between the AmeriFlux and NEON networks, and provides ideas for additional future activities. It may also be a useful example for other efforts seeking to establish successful cross-project collaborations, e.g., with NEON, AmeriFlux, and/or other networks. DOI: 10.13140/RG.2.2.29566.95040/2

White paper: On the Use of LiDAR Data at AmeriFlux Sites

December 2015: Written by Martin Beland (University of California, Berkeley), Geoffrey Parker (Smithsonian Environmental Research Center), David Harding (NASA Goddard Space Flight Center), Chris Hopkinson (University of Lethbridge), Laura Chasmer (University of Lethbridge), and Alexander Antonarakis (University of Sussex).

“Our aim is to inform the AmeriFlux community on existing and upcoming LiDAR technologies (atmospheric Doppler or Raman LiDAR often deployed at flux sites are not considered here), how it is currently used at flux sites, and how we believe it could, in the future, further contribute to the AmeriFlux vision. Heterogeneity in vegetation and ground properties at various spatial scales is omnipresent at flux sites, and 3D mapping of canopy, understory, and ground surface can help move the science forward. Systems discussed include: airborne laser scanning (ALS), terrestrial laser scanning (TLS), and portable canopy LiDAR (PCL).”

White paper: An AmeriFlux network perspective on urban and managed systems

Prepared for the U.S. DOE BERAC Workshop on the Potential Integrated Field Laboratory (IFL), January 29-30, 2015, Washington DC. Contributors (alphabetical): Gil Bohrer (Ohio State University), Lianhong Gu (Oak Ridge National Laboratory), Kevin Gurney (Arizona State University), Beverly Law (Oregon State University), Joseph McFadden (University of California, Santa Barbara), Asko Noormets (North Carolina State University), Eric Pardyjak (University of Utah), Cristina Poindexter (Lawrence Berkeley National Laboratory), Rob Stoll (University of Utah), Margaret S. Torn (Lawrence Berkeley National Laboratory)

White paper: Recommendations for Belowground Carbon Data and Measurements for the AmeriFlux Network

This 2014 white paper is written by Karis McFarlane (LLNL), Adrien Finzi (Boston U), Luke Nave (USFS) and Jim Tang (MBL). Summarizes current recommendations for measuring belowground carbon. Measuring the quantity, distribution and turnover of C belowground is fundamental to achieving AmeriFlux strategic goals that cannot be completed by eddy covariance flux measurements alone.