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Biosphere Atmosphere Exchange 1) Directly emitted GHGs CO 2, CH 4, N 2 O 2) Chemical sources of GHGs and SOA BVOCs  CO  CO 2 BVOC  aerosol 3) Effects.

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Presentation on theme: "Biosphere Atmosphere Exchange 1) Directly emitted GHGs CO 2, CH 4, N 2 O 2) Chemical sources of GHGs and SOA BVOCs  CO  CO 2 BVOC  aerosol 3) Effects."— Presentation transcript:

1 Biosphere Atmosphere Exchange 1) Directly emitted GHGs CO 2, CH 4, N 2 O 2) Chemical sources of GHGs and SOA BVOCs  CO  CO 2 BVOC  aerosol 3) Effects of biogenic emissions on O 3, OH and NO 3 NO x BVOC  H 2 CO BVOC + O 3  OH

2 What are the magnitudes of these sources? How are they distributed, in time and space? How do they impact atmospheric chemistry & global greenhouse gases? What are the emissions of “natural systems”? What are the effects of management, e.g. fertilizer, timber forests?

3 Molecules: CO 2, CO, CH 4, NO 2, O 3, H 2 CO, glyoxal Aerosol properties Satellite observations that will contribute

4 SOURCES OF ATMOSPHERIC METHANE ANIMALS 90 LANDFILLS 50 GAS 60 COAL 40 RICE 85 TERMITES 25 WETLANDS 180 BIOMASS BURNING 20 GLOBAL METHANE SOURCES (Tg CH 4 yr -1 ) Diffuse human-caused sources account for 365 in a total of 550 (70%). Agriculture accounts for 175 (30%)

5 CH 4 over North Dakota Summer, 2000 (COBRA) Growth of CH 4 slowed dramatically after 1991. Will increases resume? The vertical gradient over the Midwest is comparable to the gradient in the Amazon.

6 S. Del Grosso, S. Ogle and B. Parton, in review Total ~ 0.6 TgN/yr, 15% of global total

7 PRESENT-DAY GLOBAL BUDGET OF ATMOSPHERIC N 2 O 12 (9 – 16)SINK (Tg N yr -1 ) Photolysis and oxidation in stratosphere 4 (3 – 5)ACCUMULATION (Tg N yr -1 ) 1 (1 – 2)Industrial 2 (1 – 3)Livestock 4 (1 – 15)Agricultural soils 8 (2 – 21)Anthropogenic 2 (1 – 4)Temperate soils 4 (3 – 6)Tropical soils 3 (1 - 5)Ocean 10 (5 – 16)Natural 18 (7 – 37)SOURCES (Tg N yr -1 ) Although a closed budget can be constructed, uncertainties in sources are large! (N 2 O atm mass = 5.13 10 18 kg x 3.1 10 -7 x28/29 = 1535 Tg ) IPCC [2001]

8 2) Chemical Sources of GHGs and aerosol (BVOCs, 1000’s of compounds)  Isoprene (C 5 H 8 )  Monoterpenes (C 10 H 16 )  Oxygenated VOC  Sesquiterpenes (C 15 H 24 ) Amount Known

9 C.Warneke et al., 2002 Agriculture produces a wide variety of highly reactive hydrocarbons, often in large quantities. Concentrations and fluxes of oxygenated HCs over an alfalfa field in Colorado. Methanol Acetaldehyde Acetone Methanol Acetaldehyde Acetone Mixing ratio (ppb) Flux (mg m -2 hr -1 )

10 Secondary Organic Aerosol (SOA) Production from biogenic VOC emissions Isoprene Mono- and Sesquiterpene Emissions Oxidation Reactions (OH, O 3, NO 3 ) Nucleation (oxidation products) Growth Condensation on pre-existing aerosol Nucleation (unlikely) Graphic from M. Lunden

11 Nga et al., ES&T, 2006

12 Goldstein and Galbally, ES&T 2007 Atmospheric VOC Secondary Organic Aerosol 510-910 SOA Formation 310-720 Oxidation to CO/CO 2`` 175-375 Dry + Wet Deposition 130-270 Dry + Wet Deposition ~1300 Biogenic + Anthropogenic Global VOC Emissions Units Tg C yr -1 50-200 Oxidation to VOC/CO/CO 2

13 3) O 3, OH, NO 3 Biogenic NO x emissions: OH, NO 3, and O 3 BVOC  H 2 CO, aerosol oxidation? O 3 + BVOC  OH + products

14 Cohen Group Meeting 31 August 2005 Partitioning of Global NO x SourcesSource Tg N year -1 Fuel Consumption 25 Biomass Burning 6 Soil Emission 9 Lightning~10 Total~50 Based on Jaegle et al. Faraday Discussions, 130, 407-423, DOI: 10.1039/b502128f, 2005

15 Cohen Group Meeting 31 August 2005 SCIAMACHY Soil NO x Observations - Montana Bertram et al GRL 2005

16 Cohen Group Meeting 31 August 2005 Local Tuning of Y&L Soil NO x Model

17 Lee et al., JGR, 2006. Terpenes and isoprene are source of H 2 CO

18 Terpenes + O 3  OH + OxProducts Growing body of evidence that BVOC emissions are a strong source of OH both within the forest canopy and above.

19 Goldstein et al. GRL and ACP Chemical O 3 deposition Rapid Production of secondary VOC products Helmig et al. ES&T Sesquiterpene emissions are 20% of monoterpene emissions for several pine species Brune et al. JGR/Science Excess OH observed in regions of high biogenic emissions including ground sites in Alabama, Nashville and Michigan and from the aircraft. Higher OH reactivity than accounted for by measured VOC associated with biogenics Cohen ACP HNO 3 flux over a pine forest is upward implying 5-10 times more OH in the forest canopy than above Martinez (MPI-Mainz) Excess OH correlated with isoprene over Surinam Kulmala et al. Evidence in modeling and aerosol over forest in Finland

20 Ren, Brune, et al.

21 Summer (June-August) Blodgett Forest Farmer and Cohen, in preparation flux (ppb m s -1 ) NO 2 ∑PNs∑ANsHNO 3 mixing ratio (ppb)

22 HNO 3 flux (ppb m s -1 ) Summer—HNO 3 flux Focus on noon

23 Summer—HNO 3 flux Calculated based on deposition velocity Based on flux-gradient relationships 0.460.480.50 5 6 7 8 9 10 11 12 Height (m) HNO 3 (ppb) Chemistry

24 OH+NO 2  HNO 3 OH canopy = 3.1 x 10 7 molec∙cm -3 background OH ~5 x 10 6 molec∙cm -3 NO 2 = 300ppt Solve for OH needed to produce HNO 3 that is identified as chemical. OH = 3.1 x 10 7 molec∙cm -3 Residence time in the canopy is about 600 sec

25 -Di Carlo et al. [2004] Measured– Calculated OH Loss Inferred unmeasured reactive BVOCs. -Kulmala et al., [2000] Aerosol growth Hyytiala Forest, Finland From BVOC? -Ciccioli et al. [1999] sesquiterpenes in leaf enclosures were not observed above the canopy – Burriana orange orchard, Spain.

26 Mission Direct GHG and NOx emissions Industrial agriculture—target areas just after rain on recently fertilized fields, follow evolution over several days. Key goal verify/understand timing patterns so that can interpret satellite observations at one time of day. Forest Emissions: Reactivity, Aerosol Visit forests at that experience high T (maximum emissions). Bring new instruments capable of establishing links between BVOC emissions, OH and aerosol composition.

27 Conclusions A focussed effort aimed at understanding: the timing and spatial patterns of biogenic emissions the propagation of these emissions as a result of exchange across the PBL and convection and the gas and aerosol chemistry of emissions would likely provide exciting new scientific results.


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