1. Biogenic Emissions Modeling: MEGAN Christine Wiedinmyer, Tiffany Duhl, Ulzi Vanchindorj, Alex Guenther National Center for Atmospheric Research Tanarit Sakulyanontvittya, Jana Milford University of Colorado / Environ Serena Chung, Jack Chen Washington State University July 29, 2008WRAP Workshop

2. Emissions for Chemical Transport Models Point Area Mobile –On-road –Off-road Fire Biogenic

3. Emissions of trace gases from vegetation: Biogenic Emissions Controlling variables: - vegetation * species * vegetation density * leaf area index - meteorology * temperature * light - climate * season * water availability ….

4. Biogenic Emissions Modeling: MEGAN MEGAN: Model of Emissions of Gases and Aerosols from Nature –Based on Guenther et. al., Atmospheric Chemistry and Physics, 2006 Other papers forthcoming –134 emitted chemical species Isoprene Monoterpenes Oxygenated compounds Sesquiterpenes Nitrogen oxide Lumped to 20+ categories –1 km 2 resolution –Input files available at: http://cdp.ucar.eduhttp://cdp.ucar.edu

5. Biogenic Emissions Modeling: MEGAN MEGAN Versions –MEGAN v0.0, v0.1, v0.2, v0.3 Developed by Jack Chen (WSU) for EPA STAR Grant Emission factor maps of isoprene, monoterpenes, and other volatile organic compounds (OVOCs) developed Monthly emission activity maps applied (light, temperature and LAI – dependent). V0.3 used with global model (MOZART) –MEGAN v1.0 Isoprene only Published by Guenther et al., Atmos. Chem. & Phys., 2006 Included within Global Community Land Model (Heald et al., 2008) –MEGANv2 Includes emissions of other compounds Version 2.04 described by Sakyluononvittaya et al., ES&T, 2008 –Online within WRF-chem –Offline version runs like SMOKE processor Version 2.14 (?) Canopy model

6. EM: Emission (  g m -2 hr -1 )  : Emission Factor (  g m -2 hr -1 )  CE : Canopy Factor  age : Leaf Age Factor  SM : Soil Moisture Factor  : Loss and Production within plant canopy  LAI : Leaf Area Index Factor  P : PPFD Emission Activity Factor (light-dependence)  T : Temperature Response Factor MEGAN Framework: Calculation of emissions (Guenther et al., 2006)

7. Emission Factor Maps: Isoprene Guenther et al., AC&P, 2006

8. Emission Factor Maps: a-Pinene

9. Emission Factor Maps: Methanol

10. MEGAN Framework: simple Canopy Environment calculations For isoprene: Follow equation 14 of Guenther et al. (2006): Where T hr = hourly air temperature (K) T daily = daily average air temperature (K) representative of model simulation period C T1 = 80 C T2 = 200 For Monoterpenes: From Guenther et al., 1995

11. MEGAN v2.04 The algorithm and data for  SM and  are not yet ready. They are assigned to 1.0 The light dependent factor is only applied to fractions of emission factors based on biological function of plants. No explicit canopy model –Xuemei Wang has implemented canopy model in one version 11

12. MEGAN 2.04 Designed to work within the SMOKE framework –Specifically for regional air quality model input processing Three Modules –MG2IOAPI This module will convert text format to IOAPI-netCDF format. –MEGAN This is the primary MEGAN module. The gamma values are calculated within this module. –MG2MECH This model calculates the final emission rates and speciates and/or converts MEGAN emission output to chemical mechanism species. The current available mechanisms include CBMZ, SAPRC99, RADM2, and RACM. –Developed by Tanarit Sakulyanontvittaya (University of Colorado) with assistance from Jana Milford (U. Colorado), Christine Wiedinmyer and John Orlando ( National Center for Atmospheric Research), William Stockwell (Howard University), Greg Yarwood (ENVIRON), and Rahul Zaveri (Pacific Northwest National Laboratory). Output is I/O API file ready for input to SMKMRG

13. MEGAN INPUT FILE MEGAN input file needs to be preprocessed before model simulation –Documentation being developed –Currently requires geographic processing software File must include: –Model Grid information –Normalized Emission factors From NCAR Community Data Portal Values from downloaded grid converted from g/km2/hr to mole/km2/hr –Monthly Leaf Area Index (LAI) From NCAR Community Data Portal –Plant Functional Type (PFT) From NCAR Community Data Portal

14. MEGAN Emission Estimates: Isoprene Max = 4358 g/km 2 -hr Total average emission = 7417 tons/hr Max = 10542 g/km 2 -hr Total average emission = 12145 tons/hr Isoprene Emissions

15. MEGAN vs. BEIS3.11 Average Isoprene Emission Estimates July 2004 Serena Chung, WSU

16. Max = 77 g/km 2 -hr Total average emission = 215 tons/hr Max = 56 g/km 2 -hr Total average emission = 163 tons/hr NO Emissions MEGAN Emission Estimates: Nitrogen Oxide NO Emissions

17. Max = 852 g/km 2 -hr Total average Emission = 2205 tons/hr Max = 591 g/km 2 -hr Total average Emission = 1852 tons/hr Monoterpene Emissions MEGAN Emission Estimates: Monoterpenes Monoterpene Emissions

18. Max = 342 g/km 2 -hr Total average Emission = 786 tons/hr Max = 135 g/km 2 -hr Total average Emission = 298 tons/hr Max = 398 g/km 2 -hr Total average Emission = 786 tons/hr SQT Emissions MEGAN Emission Estimates: Sesquiterpenes

19. Summary MEGAN is a new biogenic emissions model MEGAN v2.04 is ready to be used to create model-ready biogenic emissions –Download at http://cdp.ucar.edu –Input file for MEGAN needs to be preprocessed by users Emission estimates from MEGAN have significant differences from BEIS estimates –Evaluation and validation is needed. Christine Wiedinmyer christin@ucar.edu * Limited support available

21.  P = the dependence of emissions on light This is based on equations 11-13 of Guenther et al. (2006). Where:  P = 0 when and Where  = above canopy PPFD transmission (non-dimensional) P daily = daily average above canopy PPFD (  mol m -2 s -1 ) a = solar angle (degree) where P ac = above canopy PPFD (  mol m -2 s -1 ) P toa = PPFD at the top of atmosphere (  mol m -2 s -1 ) where DOY = day of year MEGAN Framework: simple Canopy Environment calculations

22.  LAI = the dependence of the emissions on Leaf Area Index.  LAI = 0.49 * LAIc /[(1+0.2* LAIc 2 ) 0.5 ] ` Where: LAIc = leaf area index of the current month (or the month that is being simulated) MEGAN Framework: simple Canopy Environment calculations

23. Table 1: Input parameters for MEGANv2.0, including class of compound (1-20), base emission factors (  g m -2 hr -1 ) for broadleaf trees (EF BT ), Needleaf Trees (EF NT ), Shrubs (EF SHR ), and Crops/Grasses (EF CG ).  is the dimensionless parameter used to calculate  T for compounds other than isoprene. The light dependent fraction (LDF) is the fraction of the total emissions that should have a light dependency assigned. ClassName Class IDEF BT EF NT EF SHR EF GC  Leaf Age CaseLDF MBO2510080.10.0951 Myrcene32075220.30.0920.05 Sabinene44570500.70.0920.1 limonene545100520.70.0920.05 carene 618160250.30.0920.05 ocimene 790608510.0920.8 pinene 8903001001.50.0920.1 pinene 918045020020.0920.1 farnescene 106030500.90.1530.8 caryophyllene 116075651.20.1530.8 Methanol12400 0.0940 Acetone13100 0.1110 Acetaldehyde and ethanol14120 0.1310 formic acid, formaldehyde, acetic acid1570 0.0910 methane16300 0.0510.75 nitrogen gases: NO, NH3, N2O1755412000.0710 other monoterpenes1887.2180.4108.24.810.0920.1 other sesquiterpenes19107.7125.4104.41.830.1530.8 other VC20969.2 0.0910.75

24. Max = 141 g/km 2 -hr Total average Emission = 97 tons/hr Max = 23 g/km 2 -hr Total average Emission = 12 tons/hr Max = 74 g/km 2 -hr Total average Emission = 30 tons/hr SQT Emissions MEGAN Emission Estimates: Isoprene