Fire Modeling issues: fire effects on regional air quality under a changing climate

1. Fire Modeling issues:fire effects on regional air quality under a changing climate Douglas G. Fox dgfox@comcast.com

2. Land cover & land use natural landscapes managed forests rangelands agricultural lands Climate Climate change Climate variability Fire activity Wildfire wildland fire use prescribed fire agricultural burning Fire: Climate: Air Quality Air Quality Climate influences Health Particulates NAAQS SOA Visibility Radiation balance

3. Overview of predicting future fire: modeling issues • Simulating fire emissions. • Predicting fire potential: • “Critical” weather/climate conditions; • Fuels: • Amount (vegetation growth & change); • Management activity influences; • Moisture content. • Simulating fire activity: • Ignition, Intensity & Duration.

4. Fire Simulation & Linkages Future Vegetation & fuels PnET 2b Future fire potential/ activitydata Met inputs 2a Modified biogenic land use data Fire Simulator 3 BEIS 3 BlueSky-EM 1 Biogenic Emissions Fire emissions SMOKE

5. Overview of fire modeling issues • Fire Emissions • Models to calculate fire emissions; • Different characterizations of fuels; • Different characterizations of consumption; • Input uncertainties: • Fire occurrence data; • Fire size & location uncertainties. • Limited measured emission factors: • Few/no measurements of aerosol components: • OC , EC, PMC • SOA precursors

6. Overview of fire modeling issues • Fire Emissionsi= A x B x CE x ei • Emissionsiis the emission of chemical species i (in mass units); • A is the area burned; • B is the fuel loading (biomass per area); • CE is the combustion efficiency, or fraction of biomass fuel burned, and; • ei is an emission factor for species i (mass of species per mass of biomass burned)

7. Overview of fire modeling issues • BlueSky Fire emissions model: • Fuel Loading: • National Fire Danger Rating System (NFDR): • Fuel models (~ 20, mixes of size classes, loadings/size class); • Not representative of heavier fuel loadings; • National satellite derived coverage. • Fuel Characteristic Classification System • More detailed; • Three dimensional, ~ 100 • Don McKenzie will discuss.

8. NFDRS and FCCS Fuel Maps

9. Overview of fire modeling issues • BlueSky Fire emissions model: • Fuel Consumption: • EPM/CONSUME v.1.02 predicts fuel consumption as f (time) & emissions: • Estimates CO, CH4 and PM10 directly • Fire Emission Production Simulator (FEPS): • Allows 6 fuel moisture values (v dry, dry, moderate, moist, wet, v wet); • Allows flaming, smoldering & long smoldering (>2 hrs) emissions; • Estimates CO, CH4 and PM2.5 directly. • Emission Factors: • Additional species calculated from empirical relationships as a f (CO/CO2 ). • Don McKenzie will discuss.

10. Fire Emission Factors CE = DCO2 / {DCO+DCO2 + DCH4+Dother} MCE = 0.15+.86*CE D= [.]plume – [.] Emissions in g/kg

11. By NFDR model loading & consumption for the national wildfire inventory (t/a)

12. By NFDR model loading & consumption for the national wildfire inventory (t/a) From Inter RPO fire emissions inventory, Air Sciences, 2005 for WRAP

13. Regional fire days, acres, consumption & emissions for the national wildfire inventory (t/a) Data files and documentation: http://www.airsci.com/wrap/inter-rpo/

14. RPO 2002 Wildfire emissions estimate

15. Overview of fire modeling issues • Predicting fire potential: • Changes in fuels: • PnET generated landscape; • Effects of management; • Extraordinary disturbances. • “Critical” fire weather scenarios: • MACSIP generated regional meteorology; • “Critical” weather /climatic events: • Fuel moisture & drought; • Winds & storms. • Identifying fire grid cells: • Spatial links - fuels & weather – fire cells

16. Overview of fire modeling issues • Simulating fire activity: • Ignitions: • Date & time of fire starts; • Locations on the landscape; • Intensity; • Duration; • Natural vs. anthropogenic fire: • Wildfire, wildland fire use, prescribed fire

17. Overview of fire modeling issues • What are contemporary fire contributions to regional air quality? • Apportionment analysis from IMPROVE: • OC/EC ratio • Trajectory/emissions mass balance. • Regional modeling (2002) • WRAP / RMC results.

18. Fire Apportionment: • OC/EC Edge analysis: • IMPROVE Data suggest: • Urban ratio ~ 2-4 • Fire (& SOA) dominated ratio ~ 9 or higher. • Setting urban = 2.3 & fire = 9 & calculating % of fire OC • Likely to be upper bound because fire OC includes SOA. • Trajectory mass balance regression (TrMB): • Obtain fire occurrence data (location, size, time); • Parameterize fire’s contribution to site OC by summing distance weighted trajectory fire grids intersections; • Regress OC against the fire surrogate variable; • Calculate Fire OC contribution; • Likely to be lower bound because of limited fire occurrence data & transport approximations.

19. OC/EC Edge analysis: OC/EC ratios 2000 2001 2002 • Maps of annual OC/EC ratios for 2000 – 2002. • Maps are scaled the same in all years, black is where OC/EC is less than 2.3, red where it is greater than 9.

20. TrMB calculations IMPROVE sites Fire grids ATAD Trajectories • Gridded fire occurrence data serve as surrogates for fire emissions • IMPROVE data provide known receptor aerosol mass concentrations • ATAD back trajectories select fires that impact IMPROVE sites • Blue hatched regions indicate the area swept by four daily back trajectories arriving at Gila Cliffs National Monument on IMPROVE sampling days in August, 2000.

21. Apportioning Fire’s contribution:results (ug/m3) • Fire Apportioned OC Results: • OC/EC edge analysis (all biogenics): • West ~ 0.6; East ~ 0.9 • TrMB Regression (wildfires): • West ~ 0.3; East ~ 0.4 • Current OC from IMPROVE: • West ~ 1.0; East ~ 1.7 • Fire contribution to OC: • West ~ 30-60%; East ~ 24-54% OCM = 1.4*OC, avg. organic ~ 70%C

22. WRAP TSS results for Crater Lake NP

23. Anthropogenicfire component

26. Questions?