1. Estimating Biogenic VOC Emissions for the SCOS Domain Using the BEIGIS Model Michael Benjamin & Klaus Scott California Air Resources Board SCOS97 regional stakeholder modeling meeting Diamond Bar, California August 28, 2001

2. Presentation Overview BackgroundBackground BEIGIS model inputsBEIGIS model inputs Validation of BEIGIS inputsValidation of BEIGIS inputs BEIGIS results for August 3-7, 1997 episodeBEIGIS results for August 3-7, 1997 episode Comparison with other inventoriesComparison with other inventories ConclusionsConclusions

3. Background BVOCs can be significant precursors to ozone and PM2.5 formationBVOCs can be significant precursors to ozone and PM2.5 formation Accurate BVOC inventories needed for control strategy developmentAccurate BVOC inventories needed for control strategy development Complicated in California due to climatic variability and heterogeneity of vegetationComplicated in California due to climatic variability and heterogeneity of vegetation BEIGIS is an ArcView GIS application developed by ARB that uses high resolution California-specific inputsBEIGIS is an ArcView GIS application developed by ARB that uses high resolution California-specific inputs

4. BEIGIS Model Inputs Landuse and Landcover databasesLanduse and Landcover databases –GAP, county ag, SCAG, SANDAG Leafmass databasesLeafmass databases –LAI, SLW, leafmass constant Plant species emission ratesPlant species emission rates Environmental parametersEnvironmental parameters Environmental correction algorithmsEnvironmental correction algorithms

5. Southern California Vegetation Classes Source: GAP Database

6. August 1995 Leaf Area Index (LAI) Values Source: Nikolov (1999) Grid cell size = 1 km

7. August 4, 1997 Average Daily Temperatures Grid cell size = 5 km

8. Validation of BEIGIS Inputs ARB funding ground-based validation of satellite-derived GAP and LAI databasesARB funding ground-based validation of satellite-derived GAP and LAI databases Approximately 15 validation sites statewideApproximately 15 validation sites statewide GAP database correctly predicts 65-75% of species identified in ground surveysGAP database correctly predicts 65-75% of species identified in ground surveys Analysis of ground-based LAI data ongoing but preliminary results support use of Nikolov LAI databaseAnalysis of ground-based LAI data ongoing but preliminary results support use of Nikolov LAI database

9. BEIGIS Model Output Chemical species:Chemical species: –Isoprene, monoterpenes, MBO Temporal resolution:Temporal resolution: –Hourly, daily, episodic Spatial resolution:Spatial resolution: –1 km grid, 5 km grid, county, air basin

10. Isoprene Emissions 1300 Hours, August 5, 1997

11. Monoterpene Emissions 1300 Hours, August 5, 1997

12. Methylbutenol Emissions 1300 Hours, August 5, 1997

13. BEIGIS Hourly Emissions SCOS Domain August 3-7, 1997 Aug 3 Aug 4 Aug 5 Aug 6 Aug 7

14. BEIGIS Daily Emissions SCOS Domain August 3-7, 1997

15. Comparison of BVOC Inventories for the SCAQMD

16. Comparison of BVOC Inventories for SCOS Domain

17. Contribution of Biogenics to Overall ROG Inventory August 5, 1997 Including Wildfires Excluding Wildfires

18. Conclusions High resolution California-specific inputs used with BEIGIS model to estimate BVOC emissions for the SCOS domainHigh resolution California-specific inputs used with BEIGIS model to estimate BVOC emissions for the SCOS domain 450 - 700 TPD BVOC emitted in SCOS domain during August 3-7, 1997 ozone episode450 - 700 TPD BVOC emitted in SCOS domain during August 3-7, 1997 ozone episode BVOC inventory ~ 25% SCOS ROG inventory, assuming anthropogenic inventory of 2100 TPD (excluding wildfire emissions)BVOC inventory ~ 25% SCOS ROG inventory, assuming anthropogenic inventory of 2100 TPD (excluding wildfire emissions)