Introduction

1. Introduction • Welcome, logistics. • A brief history of the ChEAS. • Scope of the ChEAS – participants, projects/funds, sites, measurements. • Broader context – AmeriFlux, NACP, global flux network. • Goals for this meeting

2. Overall goals of the ChEAS • Understand northern forest-atmosphere carbon and water cycles and how they respond to • Climate variability and change • Land use change • Up-scale forest-atmosphere fluxes from chambers to forest stands, and from forest stands to all upper Midwest forests. • Down-scale atmospheric measurements to derive fluxes for the upper Midwest forests. • Evaluate regional fluxes with multiple methods, and interpret with understanding of the governing mechanisms. Guide the study of other regions.

3. A brief history of the ChEAS • Unknown date in pre-history, U. Wisconsin begins forestry research in the Chequamegon National Forest. • 1990 or so, NOAA-CMDL starts instrumenting tall towers for trace gas measurements. • December 1991, Davis and Bakwin start talking in Boulder, due to Michael Trolier and the Chemrawn VII meeting in Baltimore. • 1994. NIGEC funds Bakwin and Davis for eddy flux measurements at WLEF. NOAA-funded CO2 measurements start in 1994. Flux measurements start in 1995. AmeriFlux takes shape ~ 1996(?).

4. A brief history of ChEAS • 1997. Bolstad, Davis, Denning, Gower, Gutschick, and MacKay (others?) all begin new projects in the Chequamegon region, all focused to some extent around the WLEF flux and mixing ratio measurements. Gower organizes a winter 1998 meeting at Kemp. ChEAS is born. Bakwin creates the acronym at this meeting. • Past ChEAS meetings: • Kemp, February 1998. • St. Paul, May 1999. • St. Paul, June 2000. • Madison, June, 2001 • ChEAS RCN funded in early 2002.

5. First ChEAS RCN workshop • August, 2002, Kemp – 5 days (follow-up on interpretation of atmospheric CO2 mixing ratio measurements, Boulder, October 2002) • Included tutorial lectures, hands-on experiments and demonstrations, research presentations and discussions of future research • Gathered 25 participants, including 8 guests (6 presenting) and 8 graduate students. 11 institutions represented. • Focus: Interannual variability in CO2 and H2O fluxes in northern temperate forests. Tutorials on multiple flux measurement methods.

6. The Chequamegon Ecosystem-Atmosphere Study (ChEAS) Research Collaboration Network (RCN) • Funded by the NSF’s Biological Sciences Directorate. • 5 year project, started ~ January 2002. • Proposal written by Eileen Carey and Bruce Cook. Initiated at the suggestion of Jim Ehleringer, U.Utah, at the 4th ChEAS meeting, Madison, WI, June, 2001.

7. ChEAS RCN, continued Objectives • Provide multidisciplinary training and research opportunities to new scientists working across traditional boundaries in the fields of ecology, hydrology and atmospheric science. • Promote the development of integrative research projects building upon the ChEAS infrastructure, especially those focusing onbridging the gap between leaf- and canopy-scale flux measurements and the global CO2 flask sampling networkand understanding the causes of seasonal to interannual variability in forest-atmosphere exchanges. • Promote data sharing. • Guide the future direction of ChEAS research.

8. ChEAS RCN, continued Structure • Steering group + about 20 “core participants” (= research group leaders with research interests matching the objectives of the RCN). Open to new members. • Workshops. 2002, 2004, 2006. Funds to bring in guest scientists and participating students and scientists. 2 week duration. • ChEAS meetings, each year. 1-2 days. • Laboratory exchanges. Up to 5 visits/year, duration of 2 weeks to a few months.

9. What/Who/Where is the ChEAS?Projects, sites, participants • About 5-10 projects partly or wholly focused in the region have been ongoing since ~ 1997. At least 7 proposals are currently pending. • Online documentation of the ongoing projects has not been very good. • NOAA, NIGEC, DoE TCP, NASA Eosval, NSF Ecosystems and NSF/NCAR have provided funds. • Research has often, but not always, focused around flux towers. 7 long term and 3 portable systems are currently operating.

10. Theme PI Description Sites Funding Atmospheric carbon cycle measurements and analysis, global, continental and regional. Pieter Tans and Peter Bakwin, NOAA/CMDL Tall tower CO2 and trace gas measurements Several across the U.S. including WLEF NOAA OGP GCC Pieter Tans and Peter Bakwin, NOAA/CMDL Airborne CO2 and trace gas profiling Several across the U.S. including WLEF NOAA OGP GCC Paul Wennberg, UC Irvine FTIR measurements of CO2 column WLEF NASA Kenneth Davis, PSU, and Scott Denning, CSU Regional, seasonal atmospheric inversion study ChEAS(2003) + an NACP study area (2004) DoE TCP Jim Ehleringer, Univ. Utah Stable isotope observations, interpretation. ChEAS, other BASIN sites around the globe. GCTE Britt Stephens, NCAR O2/N2 measurements, interpretation WLEF NSF INTEX – N. America Airborne atmospheric chemistry project, 2004 ChEAS, east and west coast sites, continental transects NASA (planning underway) Steven Wofsy, Harvard COBRA – airborne Lagrangian budgets Many sites including WLEF Multiple sources Joe Berry, Carnegie Institute of Stanford Regional carbon fluxes integrated by the ABL Multiple sites. Focus on WLEF and ARM-CART towers. NASA IDS

11. Ecosystem-atmosphere flux measurements and ecosystem processes. Paul Bolstad, U. Minnesota and Kenneth Davis, PSU Multi-scale fluxes at 3 towers & related stands. WLEF, Willow Creek, Lost Creek flux towers DoE – AmeriFlux Eileen Carey, U. Minnesota Old growth chamber, plot and eddy covariance fluxes Sylvania/Helen Lake (UP of Michigan) DoE TCP Jiquan Chen, Univ. Toledo Forest age, structure, and impact on carbon balance Western district of the Chequamegon, UP of Michigan NSF Biological Sciences Davis and Arthur, PSU; Mackay, SUNY; Ewers, U. Wyoming Coupled water, CO2 and CH4 cycles in a northern forest. WLEF/ChEAS NSF Biocomplexity Jiquan Chen, Univ. Toledo Relating CO2 and CH4 fluxes to land use and climate change ChEAS/Chequamegon National Forest NASA IDS Remote sensing, modeling of ecosystem processes S. Thomas Gower, U. Wisconsin MODIS validation ChEAS, other BIGFOOT sites around the Americas. NASA Faith Ann Heinsch, U. Montana BIOME-BGC real time modeling ChEAS, other AmeriFlux sites NIGEC Great Plains G. James Collatz, NASA Goddard Disturbance history, climate, and regional carbon fluxes ChEAS, eastern VA, northern BOREAS NASA IDS Scott Mackay, SUNY Buffalo Sap flux measurements, regional flux modeling WLEF/ChEAS NASA IDS

12. ChEAS flux tower sites

13. ChEAS long-term flux towers

14. Broader context – AmeriFlux, NACP, global flux network • Analyses of multi-tower and multi-year flux datasets are becoming more common and more sophisticated. Evaluation of flux measurements with biometric data is becoming more routine. • Interest in making AmeriFlux more like a functional network is growing. • A midwest ag regional intensive for the NACP is likely. Other regional studies may be considered. • Joint synthesis of flux and mixing ratio data is becoming a very active field of research.

15. Goals of this workshop • Identify scientific opportunities and needs. • Educate ourselves, especially grad students, about these opportunities and needs. • Create a plan of action. • Examine our role in the NACP and the global flux networks and act appropriately. • Identify new collaborators who can enhance ChEAS. • Plan the 2004 ChEAS workshop and 2003-2004 lab exchanges.

16. Goals of the 1st ChEAS workshop, 2002 • Understand interannual variability in CO2 and H2O fluxes observed during ChEAS. • Understand differences in fluxes observed among ChEAS research sites. • Draft new papers and proposals following the results of our proceedings. • Includes renewals of WLEF and Willow/Lost Creek projects, due to NIGEC on 3 September, 2002. Core projects. Both rejected!

17. 2002 workshop action items • Get locations/descriptions of Chen sites added to the ChEAS web site/database. • Generate footprint models for NEE vs. GPP comparisons. Not as critical for R vs. R comparisons, since soil properties vary less in space than LAI and species composition varies. • Can someone monitor ChEAS phenology and pass the data on to M. Schwartz? Proposal rejected. • Evaluate models of CO2 transport and mixing at diurnal, synoptic and annual time scales. Observational check of the TransCom models. • Progress. Hurwitz, Bakwin, Yi papers.

18. 2002 action items, continued • Use continental [co2] data in inverse models. 1999, 2000, etc effort. Progess underway. • EDemographics and/or Biome-bgc runs of the towers, ChEAS landscape. Recruiting colleagues. • Write a caterpillars paper. Progress, B Cook. • Nighttime NEE/R at WCreek puzzle. Analyze: • Undercanopy R measurement • Daytime NEE to derive R • Chamber flux data • Nighttime above canopy R • Comparison to past literature • Progess: Many analyses; chamber flux experiment underway(?).

19. 2002 action items, continued • Lost Creek fluxes and water table paper. • Sylvania annual flux paper. Being drafted. • WLEF/WCreek/LCreek comparison work. • Why is WLEF a source of C? (Future effort with Chen portable tower at aspen stand? 2002 wet = test of wetland hypothesis. Test harvest idea with back of envelope remaining C from harvest – 30% of biomass – and time scale of decay – approx 5 years – and area harvested.) Work underway. • WLEF interannual variability. Paper outlined. Interpretation needs input from foresters.

20. 2002 action items, continued • Synoptic climatology of [co2] – connect Hurwitz and Bakwin.  • C biometry intercomparison for WCreek. • Whole canopy WUE and VPD responses vs. leaf-level responses. • Determine age of respired C at sites (esp WLEF – drying wetlands) plus respiration measurements at wetland margins. Proposals for wetland studies in. • Canopy structure and elevation from airborne lidar.   • Add someone interested in root growth, belowground processes in general. Recruit among us?

21. 2002 action items, continued • Add someone interested in ecosystem demographics and forest inventory across the entire ChEAS domain. • Enhance spatial remote sensing work to complement added spatially distributed forest inventory analyses. Complement with spatially distributed ecosystem modeling. Address all of northern Wisconsin, or even the whole lake states region. Recruiting/proposals in preparation. • Use changes in satellite data/land use over time to interpret regional fluxes in addition to FIA work. Proposal submitted.

22. 2002 action items, continued • Extend eddy covariance flux sampling (via aircraft, Chen sites) and component flux sampling across the landscape to determine the representativeness of the WLEF and WCreek/LCreek sites, and answer the problems we are having in getting the Creeks and WLEF to agree via upscaling. Proposals, some rejected. • Micromet study of possible 2-d transport. Ideas. • Do side by side measurements with a continuous chamber flux system.

23. 2002 action items, continued • Increase temporal density of the soil respiration measurements at a single forest stand to increase our ability to observe changes in the soil respiration vs. soil temperature and moisture relationships from year to year.   • Study of water dynamics and their impact on CO2 fluxes. Include methane emissions. Proposals in review.

24. Needs and opportunities, 2003(?) • ChEAS is strong in flux measurement density and quality, and inverse methods, but weak in upscaling, mechanistic interpretation of flux measurements, and data-model integration. • Current puzzles in the flux data (carbon source, upscaling difficulty, interannual changes) are scientific opportunities. • The ChEAS flux network and regional inverse study underway should be fully utilized. Unique scientific opportunities and relevance to NACP. • Publication record is slow. We need to produce publications that take advantage of existing data and results.