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Biogenic Emissions of Organics: Global Budgets and Implications. Colette L. Heald Russ Monson, Mick Wilkinson, Clement Alo, Guiling Wang, Alex Guenther Scot Martin, Qi Chen, Jose Jimenez, Delphine Farmer. IGAC Conference, Annecy, France September 11, 2008.
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Colette L. Heald
Russ Monson, Mick Wilkinson, Clement Alo, Guiling Wang, Alex Guenther
Scot Martin, Qi Chen, Jose Jimenez, Delphine Farmer
IGAC Conference, Annecy, France
September 11, 2008
C5 H8: Reactive hydrocarbon emitted from plants (primarily broadleaf trees)
Annual global emissions ~ equivalent to methane emissions
Depletes OH = ↑ CH4 lifetime
(24 hrs and 10 days)
(24 hrs, 10 days)
AMOUNT OF VEGETATION
Leaf area index (LAI)
suppressed under drought
[Guenther et al., 2006]
NPP ↑ Temperature↑
Methane lifetime increases
[Shindell et al., 2007]
SOA burden ↑ > 20%
[Heald et al., 2008]
Surface O3 ↑ 10-30 ppb
[Sanderson et al., 2003]
Isoprene emissions projected to increase substantially due to warmer climate and increasing vegetation density.
LARGE impact on oxidant chemistry and climate
Long-Term growth environment: gene adaptation
Dependent on ambient CO2
Short-term exposure: changes in metabolite pools and enzyme activity
Dependent on intercellular CO2
Empirical parameterization from plant studies [Wilkinson et al., GCB, accepted]
To what degree does this CO2 inhibition counteract predicted increases in isoprene (due to T and NPP)?
Decrease when CO2 inhibition
Isoprene emissions in 2100
See that ↑in T activity factor ~ compensated by ↓ in CO2 activity factor
Global Model: NCAR CAM3-CLM3 (2x2.5)
MEGAN with CO2 inhibition
* With fixed vegetation
Important implications for oxidative environment of the troposphere…
[Heald et al., GCB, accepted]
LARGE particles (> 10 µm)
Jaenicke  suggests may be as large a source as dust/sea salt (1000s Tg/yr)
Elbert et al.  suggest emission of fungal spores ~ 50 Tg/yr
How much does this source contribute to sub-micron OC?
Based on Elbert et al.  who summarize observed PBAP concentrations and estimate 50 Tg/yr of fungal spores emitted over entire size range.
Global Annual Mean Burden
< 1 m
Global Model: GEOS-Chem (2x2.5)
Field site: close to Manaus, Brazil (in Amazonia), Feb-Mar
No obvious indication of an important sub-micron PBAP in the “pristine” Amazon…
What about “intermediate” size range??
NEED: (1) better understanding of emission drivers
(2) More observations of PBAP
**PRELIMINARY AMS obs: Scot Martin, Qi Chen (Harvard). Jose Jimenez, Delphine Farmer (CU Boulder)
Mick Wilkinson, Russ Monson
Clement Alo, Guiling Wang
Qi Chen, Scot Martin
Delphine Farmer, Jose Jimenez