1. Development of Flux Capabilities & Recent developments at the Borden Forest Research Station Ralf Staebler

2. This presentation: 1. Fluxes 101 2. The Borden Forest Research Station 3. Ongoing & planned flux work

3.  Frequently we are actually interested not just in the concentrations, but the fluxes (i.e. what goes in and out of the box at the atmosphere’s lower boundary)  Measuring the fluxes is typically an order of magnitude more difficult (in terms of instrument requirements)  Options: Eddy Covariance Gradient methods (aerodynamic, modified Bowen Ratio & variants) (Relaxed) Eddy Accumulation Chambers Mass-balance techniques (integrated horizontal flux, horizontal mass difference,…) Hybrid measurement/modeling methods (Lagrangian dispersion)

4.  Frequently we are actually interested not just in the concentrations, but the fluxes (i.e. what goes in and out of the box at the atmosphere’s lower boundary)  Measuring the fluxes is typically an order of magnitude more difficult (in terms of instrument requirements)  Options: Eddy Covariance Gradient methods (aerodynamic, modified Bowen Ratio & variants) (Relaxed) Eddy Accumulation Chambers Mass-balance techniques (integrated horizontal flux, horizontal mass difference,…) Hybrid measurement/modeling methods (Lagrangian dispersion)

5. Comparing the methods: MethodEddy Covariance GradientRelaxed Eddy Accumulation Basis Advantages Direct Slower instruments acceptable Almost direct Slow instruments acceptable Disadvantages Fast sensors required (> 1 Hz) Indirect method Must determine eddy diffusivity K technically demanding (fast switching between up&down eddies)

6. Difference between true Eddy Accumulation and Relaxed Eddy Accumulation: EA:, where f is a flowrate proportional to w (proportionality factor B) REA:, using a fixed flowrate, proportionality factor A

7. What makes Borden useful? Close-to-ideal conditions for flux measurements (horizontal homogeneity, large fetch) Large patch of forest representative of southern Ontario (Great-Lakes-St. Lawrence Mixed Forests) Close to agricultural and urban sources (advection time ~ a few hours or less  interesting chemistry at detectable levels) Long historical record of measurements Conveniently close to Downsview and Egbert (ideal for cost-effective development work)

8. Borden Location

9. Borden Flux Tower - History 1985 detailed site characterization construction of first 45m tower (den Hartog, Neumann) 1986Turbulence profiles (den Hartog, Neumann, Shaw) LAI study (Neumann) 1988EMEFS I (Eulerian Model Evaluation Field Study) 1990EMEFS II 1993 BOREAS preparation (den Hartog, Neumann, Fuentes, Staebler, Black, Thurtell) 1995Isoprene Study (Fuentes), Radiative transfer (Staebler) Roughness Sublayer Gradients (Simpson) 1995-2003continuous flux measurements: CO2, H2O, H (33m) met: Wind speed & dir (33m, 45m) T & RH (33m, 45m) T profile (12 levels) radiation:shortwave in & out, PAR, net since July 98: PAR out, PAR at 2m soil:2 T profiles (6 levels) 2 moisture profiles (6 levels) soil heat flux (2 sites) 2004Construction of new tower, modernization & refurbishment for further research 2004-?Pollutant flux work

10. The old tower The last few days of the old tower (Jan’04)

11. The New Tower

12. Infrastructure:  New 41m tower  New 9x13’ instrument hut at the base (11m 2 )  Electricity: 200 Amp Service  10x30’ main trailer (28m 2 )  Additional lab space: (25m 2 )  Storage space: (31m 2 )

13. The “basic” tower system:

14. etc. 3D Sonic #1 Soil Logger Tprof Logger Met Logger 23X 3D Sonic #2 Licor #1 Cyclades Multi-Serial Port PC, Linux Operating System Network Link To Windows PC Data Acquisition Hardware Links Licor #2 RS-232 lines

15. Software links Merger Program "rtm" Analysis Program (bordenrere): - averaging - mean removal - moments - crossproducts - power spectra - covariance spectra - autocorrelation functions - crosscorrelation functions Analysis Output Files ("*.bin”) Serial Stream Capture Programs ("robot") SSCP #1 Transient data file (*.ttyC0) Transient data file (*.ttyC0) Transient data file (*.ttyC0) "Robot #1" "Robot #2" "Robot #1" Transient data file (*.ttyC2) "Robot #1" "Robot #3" "Robot #1" SSCP #2 Transient data file (*.ttyC1) "Robot #1" SSCP #3 SSCP #4 Transient data file (*.ttyC0) Transient data file (*.ttyC0) Transient data file (*.ttyC0) Transient data file (*.ttyC1) "Robot #1" "Robot #3" Transient data file (*.ttyC3) Transient data file (*.ttyC0) Transient data file (*.ttyC0) Transient data file (*.ttyC0) SSCP #5 Transient data file (*.ttyC4) "Robot #1" SSCP #6 Raw Data Files (*.rwb) Display Programs Transient data file (*.ttyC5)...... Data Acquisition Software Links

16. Screenshot

17. Forest fluxes of NH 3, SO 2, O 3 – why should we care? CE business line: “understanding … the environmental and human health threats posed by toxic substances and other substances of concern.” Forests cover 66% of Ontario Forest health affected (ozone damage; acidification; eutrophication) Dry deposition important process in regional air-quality models Interesting chemistry at the atmosphere/forest interface (esp. so close to pollutant source regions)

18. Current dry deposition short-comings: Most current dry deposition parameterizations based on scant measurements of O 3 and SO 2 Resistances for all other species are usually estimated based on linear combinations of the physical characteristics (solubility, reactivity) of O 3 and SO 2 Very limited data on NH 3 compensation points in forests Not much continuous data on intra-seasonal variability of deposition velocities Spotty understanding of the detailed physics of exchange processes How we plan to improve AURAMS & CHRONOS: Measure fluxes of O 3, SO 2 and other compounds Provide intra-seasonal, continuous fluxes of key species Provide compensation points Provide insights into processes through simultaneous, high time resolution measurements of fluxes and environmental controlling parameters Provide details on co-deposition of O 3, NH 3 and SO 2

19. Current extra measurements: First EC fluxes of NH 3 over a forest, with Guelph TGA

21. What’s Next: Winter 2004/05: assembly and lab testing of fast O 3 sensor and denuder-based REA system Spring/Summer 2005:field testing of REA and O 3 systems (4-8 weeks), more TDL NH 3 flux measurements Summer/Fall 2005:Evaluation of results; development of quasi-real-time REA system with in-situ analyzers Initial modeling activities Fall/Winter 2005:Report on first field intensive Down the road: Modification of REA system to include HNO 3,NO 2 … Aerodyne AMS at Borden: aerosol fluxes PTR-MS: biogenic VOC fluxes

22. Questions/Comments?