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Tower - Region - Continent - Globe: Bridging the gap between flux towers and flasks

Tower - Region - Continent - Globe: Bridging the gap between flux towers and flasks. Goals Merge our mechanistic understanding of terrestrial C dynamics at the tower scale with our understanding of the global CO 2 budget obtained from the flask network.

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Tower - Region - Continent - Globe: Bridging the gap between flux towers and flasks

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  1. Tower - Region - Continent - Globe: Bridging the gap between flux towers and flasks Goals Merge our mechanistic understanding of terrestrial C dynamics at the tower scale with our understanding of the global CO2 budget obtained from the flask network. Understand the mechanisms that govern changes in the atmospheric CO2 budget at seasonal to annual time scales, and regional to continental spatial scales.

  2. Contributors M.P. Butler, K.J. Davis, M. Hurwitz, D. Ricciuto, W. Wang, and C. Yi, The Pennsylvania State University B.D. Cook, University of Minnesota P.S. Bakwin, NOAA/CMDL A.S. Denning and colleagues, Colorado State J. Berry, B. Helliker, Carnegie Institute B. Balsley, J. Birks, M. Jensen, and K. Schultz, University of Colorado Support: NIGEC, DoE-TCP, NASA, NSF Related talks: Schmid, Wofsy, Hollinger, Denning, Keeling

  3. Methods for determining NEE of CO2Methods for bridging the gap Upscale via ecosystem models and networks of towers. Move towards regional inverse modeling

  4. Atmospheric approaches to determining NEE of CO2 Time rate of change of CO2 Mean transport Turbulent transport (flux) Source in the atmosphere Average over the depth of the atmosphere (or the ABL): F0C encompasses all surface exchange: Oceans, deforestation, terrestrial uptake, fossil fuel emissions. Inverse study: Observe C, model U, derive F Flux study: Observe F directly

  5. Progress • AmeriFlux towers can be used to monitor continental boundary layer [CO2]! Downscale inversions. dC/dt, dC/dx Future: Create this network. Complement tall towers, airborne profiles, satellite [CO2].

  6. Surface layer towers can (should!) be used to monitor continental CO2

  7. The seasonal amplitude of the gradient in CO2 between the continental ABLand the marine boundary layer is large. Surface layer - mid-ABL difference (1 to 2 ppmv) does not overwhelm this signal.

  8. Progress • Coherence among continental-scale, annual and seasonal flux anomalies exists and is reflected in the atmospheric CO2 network. Upscale fluxes. F0CDownscale inversions (in time). Future: Continue analyses. Incorporate flux data into inversion models. Explain 1998 anomalous increase in atmospheric CO2?

  9. Spatial coherence of seasonal flux anomalies A similar pattern is seen at several flux towers in N. America and Europe. Three sites have high-quality [CO2] measurements + data at Fluxnet (NOBS, HF, WLEF). The spring 98 warm period and a later cloudy period appear at all 3 sites.

  10. Detection of the spring 98 anomaly via oceanic flasks? 2 Alaskan flask sites have slightly higher [CO2] in the spring of 98. Mace Head, Ireland shows a depression of [CO2] in the spring of 98. Potential exists to link flux towers with seasonal inverse studies.

  11. Progress • ABL budgets are being used to derive regional, daily NEE of CO2. Downscale inversions. COBRA, Powered parachute, tower-based. • Lagrangian budgets. COBRA. • Advection in the continental ABL [CO2] cannot be neglected on monthly time scales. U dC/dx. • Synoptic events drive advection of CO2. U dC/dx. • Promising results using H2O - CO2 similarity. Helliker and Berry. Future: Continental [CO2(x,y,z)] network is required. Critical method for model validation at large time and space scales.

  12. Flux 1: surface flux using vertical advection, storage flux, and turbulent flux Flux 2: surface flux using storage flux and turbulent flux Flux 3: surface flux using an ABL budget based on PPC data ABL budgets - regional inverse studies

  13. CO2 advection in the continental ABL CO2 Si (F0C.Dt)i

  14. CO2 advection in the continental ABL

  15. Synoptic variability in CO2

  16. Regional fluxes from H2O - CO2 similarity From Helliker and Berry, poster.

  17. Progress • The rectifier effect - a major source of uncertainty in transport models - is being quantified via observations. COBRA. Powered parachute. WLEF ABL radar deployment. Improve inversions. FzC and z. Future: Examine conclusions with more continental profile data, including airborne data and additional AmeriFlux/Fluxnet sites. Validate tower-based assessment with airborne profiles. Quantify transport between the continental ABL and the marine boundary layer.

  18. Rectifier is underestimated in the day? WLEF tower + ABL radar vs. Denning 1995 model.

  19. Rectifier is overestimated seasonally? WLEF tower + ABL radar vs. Denning 1995 model.

  20. Research needed • Construct a continental [CO2] network. Make AmeriFlux towers part of this network. Move towards regional inversions and assimilation of flux and mixing ratio data into coupled ecosystem-atmosphere models. • Increase the AmeriFlux/Fluxnet database. Include [CO2]. Report data! Common formats/QC! • Continue to analyze spatial patterns in flux measurements to link to the mechanisms of global CO2 variability. • Airborne flux - modeled flux - ABL budget/regional inversion joint projects. • Conduct the North American Carbon Program.

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