## A Ta le of T

woM odels: A Comparison of the Biogenic Emission InventorySystem (BEIS3.14) and Model of Emissions of Gases and Aerosols from Nature (MEGAN 2.04) 

# What are the major differences in these tw o

Office of Research and Development National Exposure Research Laboratory | Atmospheric Modeling and Analysis Division | 

### George Pouliot 7 th 

### Annual CMAS Conference 7 October 2008 

# differences in these tw o models that estimate emissions from biogenic sources? It was the best of times, it was the worst of times, it was the age of wisdom, ...

### 1. Brief introduction to MEGAN and BEIS

• Biogenic Emissions Inventory System (BEIS v3.14) • Model of Emissions of Gases and Ae rosols from Nature (MEGA N v2 .04) 

### 2. Spatial differences betw een tw o models for an annual simulation



# To pics to be Discussed

Office of Research and Development National Exposure Research Laboratory | Atmospheric Modeling and Analysis Division | 1 

### 3. Te mporal differences betw een the tw o models 4. Future Work

# Details about BEIS3.14

• Based on BELD3 vegetation database (limited to North Am erica) • Emission factors derived for USGS land use ty pes, crops, and specific tree ty pes • Soil NO algorithm is a function of temperature, rainfall, and grow ing season (Yienger and Levy, 1 995)

Office of Research and Development National Exposure Research Laboratory |Atmospheric Modeling and Analysis Division | 2 • Simple canopy

m odel for Light adjustment • Summer/Winter factors based on freeze dates

# Details about MEGANv2.04

• Gridded emission factors based on global datasets for 11 species • Emission factors for all other species based on 4 functional plant ty pes (broadleaf, needles, shrubs, etc) • NO emission estimates are a function of temperature only • Simple parameterization of canopy l ight attenuation in V ersion 2.04;

Office of Research and Development National Exposure Research Laboratory |Atmospheric Modeling and Analysis Division | 3 • Simple parameterization of canopy l ight attenuation in V ersion 2.04; Ve rsion 2.10 w ill have an explicit canopy m odel • Monthly

g ridded leaf area indices (LAIs) used for seasonal variation Guenther

, A. , T . Karl, et al. (2006). "Estimates of global terrestrial isoprene emissions using MEGAN (Model of Emissions of Gases and Ae rosols from Nature)." At mos. Chem. Phys. 6 (1 1): 3181 - 3210.

# Isopr ene Emissions(MG/yr)

BEIS MEGAN

Office of Research and Development National Exposure Research Laboratory |Atmospheric Modeling and Analysis Division | Bi og eni c I so pre ne Anthrop og eni c I so pre ne Other Biog eni c VOCs Other Anthrop og eni c VOCs

# Monot erpenes Emissions (Mg /yr)

BEIS MEGAN Hot spot decrease

Office of Research and Development National Exposure Research Laboratory |Atmospheric Modeling and Analysis Division | Bi og eni c Monoter pe nes Anthrop og eni c mo noter pe nes Other Biog eni c VOCs Other Anthrop og eni c VOCs

# Sesquit erpenes Emissions (Mg /yr)

BEIS MEGAN

Office of Research and Development National Exposure Research Laboratory |Atmospheric Modeling and Analysis Division | Bi og eni c sesq ui te rpe nes Anthrop og eni c se squ iter pe nes OtherBi og eni c VOCs OtherAnthrop og eni c VOCs

# Methanol Emissions (Mg /yr)

BEIS MEGAN

Office of Research and Development National Exposure Research Laboratory |Atmospheric Modeling and Analysis Division | Bi og eni c M ethanol Anthrop og eni c M ethanol OtherBi og eni c VOC s OtherAnthrop og eni c VOC s

# Fo rmaldeh yd e Emissions (Mg /yr)

BEIS MEGAN

Office of Research and Development National Exposure Research Laboratory |Atmospheric Modeling and Analysis Division | 

### Bi og eni c fo rma ld ehyde Anthrop og eni c fo rma lde hyde OtherBi og eni c VOC s OtherAnthrop og eni c VOC s

# Soil Nitric Oxide

BEIS MEGAN

Office of Research and Development National Exposure Research Laboratory |Atmospheric Modeling and Analysis Division |



## Ant hrop og eni c Nox Bi og eni c Nox

# Summary of Spatial Differences
• Isopr ene: R ela tiv e to BEIS, MEGAN generate s higher isopr ene in all ar eas, especially the southern U .S. • Monoterpenes: MEGAN is lower in Canada, southwestern U. S., and northwestern U .S. • Sesquit erpenes: MEGAN is lower in midwestern U .S.

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## • Sesquit erpenes: MEGAN is lower in midwestern U .S. • Methanol: MEGAN is higher in all ar eas • Fo rmaldeh yde: MEGAN is lower in all ar eas, especially the southwestern U .S.

# Pe rc en t Difference BEIS and ME GAN (based on 2003 annual emissions sapr c99) + MEGAN is higher
- BEIS is higher isoprene 60% methanol 139% monoterpenes -40% acetone 12% sesquiterpenes - 19% Nitric Oxide - 72% Formaldehyde - 71%

Office of Research and Development National Exposure Research Laboratory |Atmospheric Modeling and Analysis Division | 11 Formaldehyde - 71% OLE1 - 63% OLE2 - 37% RCHO - 93% ALK1 - 92% ALK2 - 95% ALK3 - 63% ethene 23% carbon monoxide - 14%

# Isopr ene 36km daily domain to ta ls 2003
2500 3000 3500 4000 4500ISOPRENE (Mmol/day)

Office of Research and Development National Exposure Research Laboratory | Atmospheric Modeling and Analysis Division | 0 500 1000 1500 2000 1 21 41 61 81 101 121 141 161 181 201 221 241 261 281 301 321 341 361 DA Y OF THE Y EARISOPRENE (Mmol/day)

MEG AN BEI S

# Monoterpenes 36km daily domain to ta ls 2003
300000 400000 500000 600000MONOTERPENES (kmol/day)

Office of Research and Development National Exposure Research Laboratory | Atmospheric Modeling and Analysis Division | 0 100000 200000 300000 1 22 43 64 85 106 127 148 169 190 211 232 253 274 295 316 337 358 DA Y OF YEARMONOTERPENES (kmol/day)

MEGAN BEI S

# Sesquit erpenes 36km daily domain t ot als 2003
20000 25000 30000 35000 40000 45000 50000SESQUITERPENE (kmol/day)

Office of Research and Development National Exposure Research Laboratory | Atmospheric Modeling and Analysis Division | 0 5000 10000 15000 20000 1 22 43 64 85 106 127 148 169 190 211 232 253 274 295 316 337 358 DA Y O F YEARSESQUITERPENE (kmol/day)

MEG AN BEI S

# Methanol 36km daily domain to ta ls 2003 1500 2000 2500 3000Methanol (Mmol/day)

Office of Research and Development National Exposure Research Laboratory | Atmospheric Modeling and Analysis Division | 0 500 1000 1500 1 21 41 61 81 101 121 141 161 181 201 221 241 261 281 301 321 341 361 DA Y O F YEARMethanol (Mmol/day)

MEG AN BEI S

# Fo rmaldeh yd e 36km daily domain to ta ls 2003
150 200 250 300FORMALDEHYDE (kmol/day)

Office of Research and Development National Exposure Research Laboratory | Atmospheric Modeling and Analysis Division | 0 50 100 150 1 21 41 61 81 101 121 141 161 181 201 221 241 261 281 301 321 341 361 DA Y O F THE YEARFORMALDEHYDE (kmol/day)

MEGAN BEI S

# Soil Nitric Oxide 36km daily domain to ta ls 2003 150000 200000 250000NO FLUX (kmol/day)

Office of Research and Development National Exposure Research Laboratory | Atmospheric Modeling and Analysis Division | 0 50000 100000 1 22 43 64 85 106 127 148 169 190 211 232 253 274 295 316 337 358 DA Y O F THE YEARNO FLUX (kmol/day)

MEGAN BEI S

# Summary
• Comparison of BEIS3.14 and ME GAN2.04 made for 2003 fo r SAPRC99 mechanism species • ME GAN is higher fo r Isopr ene, methanol, acet one, ethene • BEIS is higher fo rMonoterpenes, sesquiterpenes,

Office of Research and Development National Exposure Research Laboratory | Atmospheric Modeling and Analysis Division | 18 

# • BEIS is higher fo rMonoterpenes, sesquiterpenes, fo rmaldeh yd e, other V OCs, soil NO • BEIS has a mor e det ailed soil NO algorithm • ME GAN and BEIS ha vedifferen t spatial patte rns (differen t normaliz ed emission inputs)

# Future Wo rk
• Compar e CMA Q re sults fo r BEIS3.14 and ME GAN2.04 fo r 3 week period in 2003 • Incorporate MEGAN into CMA Q as an option compar ed t o BEIS • ME GANv2.10 is e xpect ed by the end of the y ear (will

Office of Research and Development National Exposure Research Laboratory | Atmospheric Modeling and Analysis Division | 19 

# • ME GANv2.10 is e xpect ed by the end of the y ear (will include updated canopy model) • Ev en tually ma y replace BEIS with ME GAN
• Disclaimer: Although this work w as reviewed by EP A and approved for publication, it ma y not necessarily r eflect official Agency policy