Estimating Biogenic VOC Emissions for the SCOS Domain Using the BEIGIS Model

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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
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Presentation Overview

• Background
• BEIGIS model inputs
• Validation of BEIGIS inputs
• BEIGIS results for August 3-7, 1997 episode
• Comparison with other inventories
• Conclusions

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Background

• BVOCs can be significant precursors to ozone and
  PM2.5 formation
• Accurate BVOC inventories needed for control
  strategy development
• Complicated 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
  inputs

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BEIGIS Model Inputs

• Landuse and Landcover databases
• GAP, county ag, SCAG, SANDAG
• Leafmass databases
• LAI, SLW, leafmass constant
• Plant species emission rates
• Environmental parameters
• Environmental correction algorithms

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Southern California Vegetation Classes
Source GAP Database
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August 1995 Leaf Area Index (LAI) Values
Source Nikolov (1999)
Grid cell size 1 km
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August 4, 1997 Average Daily Temperatures
Grid cell size 5 km
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Validation of BEIGIS Inputs

• ARB funding ground-based validation of
  satellite-derived GAP and LAI databases
• Approximately 15 validation sites statewide
• GAP 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
  database

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BEIGIS Model Output

• Chemical species
• Isoprene, monoterpenes, MBO
• Temporal resolution
• Hourly, daily, episodic
• Spatial resolution
• 1 km grid, 5 km grid, county, air basin

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Isoprene Emissions1300 Hours, August 5, 1997
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Monoterpene Emissions1300 Hours, August 5, 1997
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Methylbutenol Emissions1300 Hours, August 5, 1997
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BEIGIS Hourly EmissionsSCOS Domain August 3-7,
1997
Aug 3
Aug 4
Aug 5
Aug 6
Aug 7
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BEIGIS Daily EmissionsSCOS Domain August 3-7,
1997
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Comparison of BVOC Inventories for the SCAQMD
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Comparison of BVOC Inventories for SCOS Domain
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Contribution of Biogenics to Overall ROG
InventoryAugust 5, 1997
Including Wildfires
Excluding Wildfires
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Conclusions

• High 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 episode
• BVOC inventory 25 SCOS ROG inventory, assuming
  anthropogenic inventory of 2100 TPD (excluding
  wildfire emissions)