Arlene M. Fiore 1 (arlene.fiore@noaa), Larry W. Horowitz 1 , J. Jason West 2
1
A21E-0863 Connecting Climate and Air Quality: Tropospheric Ozone Response to Methane Emission Controls Arlene M. Fiore 1 ([email protected]), Larry W. Horowitz 1 , J. Jason West 2 1 NOAA Geophysical Fluid Dynamics Laboratory, Princeton, NJ 2 Atmospheric and Oceanic Sciences Program and Woodrow Wilson School, Princeton University, Princeton, NJ Methane source location has little influence on the surface (or tropospheric) O 3 distribution (<10% globally except for localized effect in Asian source region) Larger ozone response in downwelling regions and locations with NO x -saturated chemistry Largest % decreases occur in lower troposphere (due to T dependent k OH-CH4 ) Characterize the O 3 response to CH 4 control Quantify the climate and air quality benefits from CH 4 controls Evaluate CH 4 controls in future emission scenarios where emissions of other O 3 precursors are also changing 1. Introduction Methane (CH 4 ) oxidation in the presence of nitrogen oxides (NO x ) contributes to tropospheric ozone (O 3 ), raising baseline levels of ozone pollution in surface air globally. Since methane is also a potent greenhouse gas, controls on methane offer a strategy for jointly addressing air pollution and climate goals [e.g., Fiore et al., 2002; Dentener et al., 2005; West and Fiore, 2005; EMEP, 2005]. Objectives 3. Ozone Response to Methane Controls in Idealized Scenarios Simulations with global anthropogenic CH 4 emissions decreased by 30%, either: (1) uniformly worldwide, or (2) entirely from Asia 2. Transient Methane Simulations with MOZART-2 • global 3D model of tropospheric chemistry • ~100 gas and aerosol species, ~200 reactions • 1.9 o latitude x 1.9 o longitude x 28 vertical levels • multi-decadal, full-chemistry simulations • Idealized scenarios: Emissions representative of early 1990s, as described in Horowitz et al. [2003] except for wetland emissions which we increased by 58 Tg yr -1 to match recent estimates; 1990-2004 NCEP meteorology recycled after 15 years • Future scenarios: Current Legislation Emissions (CLE) 2000 to 2030 [Dentener et al., 2005]; biomass burning GFED v.1 [van der Werf et al., 2003]; wetland distribution from Wang et al. [2004]; 2000-2004 NCEP meteorology recycled every 5 years Acknowledgments Funding from Luce Foundation via Clean Air Task Force; Ellen Baum (CATF), Joe Chaisson (CATF), Chip Levy (GFDL), Vaishali Naik (Princeton), and Dan Schwarzkopf (GFDL) for insightful conversations; Frank Dentener (JRC-IES) for providing the baseline CLE emissions. References Dentener, F., et al. (2005) Atmos. Chem. Phys. 5, 1731-1755. Fiore, A.M., et al. (2002) Geophys. Res. Lett., 29, 1919. Friedenreich, S.M. and V. Ramaswamy (1999) J. Geophys. Res., 104, 31389-31409. GFDL GAMDT (2004), J. Climate, 17, 4641-4673. Anthropogenic CH 4 Emissions (Tg yr -1 ) Control scenarios reduce 2030 emissions relative to CLE by: A) -75 Tg (18%) B) -125 Tg (29%) C) -180 Tg (42%) CLE +29% from 2005 to 2030 CLE increases surface CH 4 by 240 ppbv; tropospheric O 3 by 15 Tg; surface O 3 by 1.4 ppbv (2026-30 mean – 2005-9 mean). Scenario C decreases CH 4 by 540 ppb relative to CLE 2030, by 260 ppb relative to CLE 2005, and roughly stabilizes surface O 3 despite 5 Tg N yr -1 increase in anthropogenic NO x emissions. 4. Future Methane Control Scenarios Methane emissions in MOZART-2 SPATIAL DISTRIBUTION Anthropogenic CH 4 contributes: ~50 Tg (~15%) to tropospheric O 3 burden ~5 ppbv to surface O 3 LINEARITY Change in O 3 burden (Tg) Change in anthropogenic CH 4 emissions (Tg yr -1 ) MOZART-2 (this work; West et al., 2006) TM3 [Dentener et al., 2005] GISS [Shindell et al., 2005 GEOS-CHEM [Fiore et al., 2002] IPCC TAR [Prather et al., 2001] X Standard (1990s) CLE (2005) CLE (2030) Simulation s Idealize d Future Anthrop. 261 332 428 Biogenic* 214 222 222 Biomass Burning 72 23 23 Total 547 577 673 *Biogenic includes wetlands, oceans, and termites 5. Conclusions CLE A B C 0.2 0.1 0.0 -0.2 -0.1 OZONE METHANE W m -2 +0.16 Net Forcing +0.08 0.00 -0.08 Radiative forcing from 2005 to 2030 We calculate CH 4 forcing from an analytical expression [Ramaswamy et al., 2001] and O 3 forcing with the GFDL AM2 radiative transfer model [Freidenreich and Ramswamy, 1999; Schwarzkopf and Ramaswamy, 1999; GFDL GAMDT, 2004] Annual Mean Daily Max 8-hr Ozone (ppbv) 0 2 4 6 8 10 12 14 16 18 D JF M AM JJA SON USA 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 D JF M AM JJA SON Europe C LE 2005 C LE 2030 A 2030 B 2030 C 2030 0 5 10 15 20 25 30 D JF MAM JJA SON South Asia Global anthropogenic CH 4 emissions decreased uniformly by 30% Simulation (1) - Base TIME SCALE Nearing a new steady- state after 30 years Anthrop. NO x increases by 5.3 Tg N yr -1 (+19%) Anthrop. CO decreases by 44 Tg CO yr -1 (-10%) Anthrop. NMVOC increase by 3 Tg C yr -1 (+3%) EMISSIONS GLOBAL ANNUAL MEAN RESULTS IMPACTS ON CLIMATE IMPACTS ON AIR QUALITY Percentage of model grid box-days where daily max 8-hour O 3 exceeds 70 ppbv by season and region Change in daily max 8-hour O 3 (scenario B – CLE) in the season with max occurrences above 70 ppbv • Spatial pattern of O 3 response is largely independent of CH 4 source location, but depends strongly on NO x distribution • Magnitude of the O 3 response is approximately linear with reductions in anthropogenic CH 4 emissions (~0.1 Tg tropospheric O 3 per Tg yr -1 anthropogenic CH 4 reduced) • O 3 decrease from CH 4 controls is typically maximum near the middle of the total O 3 distribution, (e.g. 40-70 ppbv total O 3 ), but also extends to the high end of the distribution in NO x -saturated conditions (Los Angeles, Houston) • Future CH 4 controls relative to the CLE baseline (scenarios B or C) would offset the projected positive climate forcing and reduce the incidence of high-O 3 events in all regions, even improving air quality in Europe relative to 2005. CLE 2030 daily max 8-hr average O 3 (ppbv) Each point represents one daily maximum 8- hour average O 3 value in one model grid cell from Jun 1 to Aug 31 Composite maximum difference in U.S. daily max 8-hour mean ozone JJA (year 30) -8 -7 -6 -5 -4 -3 -2 ppbv Locations with NO x -saturated chemistry -1.75 -1.50 -1.25 -1.00 -0.75 -0.50 -0.25 ppbv Decrease in global July mean O 3 at simulation year 11 Emission reduction in Asia Globally uniform emission reduction Percentage difference (Asia – uniform)/ Asia -10 -5 -1 1 5 10 20 30 40 % Enhanced effect in source region <10% other NH source regions <5% rest of NH <1% most of SH Surface O 3 (ppbv) Tropospheric O 3 Burden (Tg) < 0.3 0.8 1.4 1.9 2.5 Surface NO x emissions 2030:2005 ratio 0 5 10 25 50 75 100 125 150 175 mW m -2 TROPOSPHERIC OZONE Surface CH 4 (ppb) CLE B C A 0 2 4 6 8 10 12 D JF M AM JJA SON Africa Difference: Scenario B 2030 – CLE 2030 Methane contribut ion increases with total O 3 until ~60-80 ppbv then saturates 0 50 100 150 200 2 0 -2 -4 -6 EUROPE JJA Mean of 10 ppb bins 2 0 -2 -4 -6 0 50 100 150 200 AFRICA JJA 0 50 100 150 200 SOUTH ASIA MAM 2 0 -2 -4 -6 Max impact from CH 4 at 40-60 ppbv total O 3 Increased incidence of O 3 > 70 ppbv in CLE from 2005 to 2030 occurs in all regions and seasons Aggressive CH 4 controls (B and C) more than offset projected increases in high-O 3 events in Europe Max CH 4 impact at ~40-70 ppbv total O 3 , plus some high-O 3 events Aggressive CH 4 reductions (scenarios B and C) offset the positive forcing predicted under the CLE baseline EMEP (2005), EMEP/CCC-Report 1/2005, Norwegian Institute for Air Research, Norway. Horowitz, L.W. et al. (2003), J. Geophys. Res., 108, 4784. Prather, M.J. et al. (2001) in Climate Change 2001, ed. J.T. Houghton et al., pp. 239-287, Cambridge University Press. Ramaswamy, V. et al. (2001) in Climate Change 2001, ed. J.T. Houghton et al., pp. 349-416, Cambridge University Press. Schwarzkopf, M.D. and V. Ramaswamy (1999) J. Geophys. Res., 104, 9467-9488. Shindell et al. (2005) Geophys. Res. Lett., 32, L040803. Wang, J.S. et al. (2004) Global Biogeochem. Cycles, 18, GB3011. West and Fiore (2005) Environ. Sci. Technol, 39, 4685-4691. West et al. (2006) Proc Natl Acad. Sci., 103, 3988-3993. van der Werf, G.R. et al. (2003) Global Change Biol., 9, 547-562. 0 -2 -4 -8 -10 -12 -6 0 -50 -100 -300 -350 -400 -200 -250 -150 Surface Methane (ppb) Tropospheric O 3 Burden (Tg) 0 5 10 15 20 25 30 Difference: CLE 2030 – CLE 2005 Largest increases occur over SE Asia (up to 20 ppbv). Growth in ship NO x emissions raises O 3 by a few ppbv over the N. Atlantic (see above for NO x emission changes) Surface O 3 at N tropics and mid-latitudes shows largest response to CH 4 controls; largest decreases occur in high-NO x areas Black boxes indicate regions analyzed below CLE 2030 Change in zonal mean O 3 (year 30) -5 -4 -3 -2 -1 0 % -2.0 -1.5 -1.0 -0.5 0.0 ppb Latitude Absolute change Percentage change -50 0 50 -50 0 50 200 400 600 800 200 400 600 800 Pressure USA JJA 0 50 100 150 200 2 0 -2 -4 -6 Color-coded by U.S. region NE SE SW NW
description
Surface CH 4 (ppb). CLE. Anthropogenic CH 4 Emissions (Tg yr -1 ). A. CLE +29% from 2005 to 2030. B. Control scenarios reduce 2030 emissions relative to CLE by: A) -75 Tg (18%) -125 Tg (29%) -180 Tg (42%). C. < 0.3 0.8 1.4 1.9 2.5. 0.2. - PowerPoint PPT Presentation
Transcript of Arlene M. Fiore 1 (arlene.fiore@noaa), Larry W. Horowitz 1 , J. Jason West 2
A21E-0863 Connecting Climate and Air Quality: Tropospheric Ozone Response to Methane Emission ControlsArlene M. Fiore1 ([email protected]), Larry W. Horowitz1, J. Jason West2
1NOAA Geophysical Fluid Dynamics Laboratory, Princeton, NJ 2Atmospheric and Oceanic Sciences Program and Woodrow Wilson School, Princeton University, Princeton, NJ
Methane source location has little influence on the surface (or tropospheric) O3 distribution
(<10% globally except for localized effect in Asian source region) Larger ozone response in downwelling regions and locations with NOx-saturated chemistry Largest % decreases occur in lower troposphere (due to T dependent kOH-CH4)
Characterize the O3 response to CH4 control Quantify the climate and air quality benefits from CH4 controls Evaluate CH4 controls in future emission scenarios where emissions of other O3 precursors are
also changing
1. Introduction Methane (CH4) oxidation in the presence of nitrogen oxides (NOx) contributes to tropospheric ozone (O3), raising
baseline levels of ozone pollution in surface air globally. Since methane is also a potent greenhouse gas, controls on methane offer a strategy for jointly addressing air pollution and climate goals [e.g., Fiore et al., 2002; Dentener et al., 2005; West and Fiore, 2005; EMEP, 2005].
Objectives
3. Ozone Response to Methane Controls in Idealized Scenarios
Simulations with global anthropogenic CH4 emissions decreased by 30%, either: (1) uniformly worldwide, or (2) entirely from Asia
2. Transient Methane Simulations with MOZART-2• global 3D model of tropospheric chemistry
• ~100 gas and aerosol species, ~200 reactions
• 1.9o latitude x 1.9o longitude x 28 vertical levels
• multi-decadal, full-chemistry simulations
• Idealized scenarios: Emissions representative of early 1990s, as described in Horowitz et al. [2003] except for wetland emissions which we increased by 58 Tg yr -1 to match recent estimates; 1990-2004 NCEP meteorology recycled after 15 years
• Future scenarios: Current Legislation Emissions (CLE) 2000 to 2030 [Dentener et al., 2005]; biomass burning GFED v.1 [van der Werf et al., 2003]; wetland distribution from Wang et al. [2004]; 2000-2004 NCEP meteorology recycled every 5 years
Acknowledgments Funding from Luce Foundation via Clean Air Task Force; Ellen Baum (CATF), Joe Chaisson (CATF), Chip Levy (GFDL), Vaishali Naik (Princeton), and Dan Schwarzkopf (GFDL) for insightful conversations; Frank Dentener (JRC-IES) for providing the baseline CLE emissions.
ReferencesDentener, F., et al. (2005) Atmos. Chem. Phys. 5, 1731-1755.Fiore, A.M., et al. (2002) Geophys. Res. Lett., 29, 1919.Friedenreich, S.M. and V. Ramaswamy (1999) J. Geophys. Res., 104, 31389-31409.GFDL GAMDT (2004), J. Climate, 17, 4641-4673.
Anthropogenic CH4 Emissions (Tg yr-1)
Control scenarios reduce 2030 emissions relative to CLE by:A) -75 Tg (18%)B) -125 Tg (29%)C) -180 Tg (42%)
CLE +29% from 2005 to 2030
CLE increases surface CH4 by 240 ppbv; tropospheric O3 by 15 Tg; surface O3 by 1.4 ppbv (2026-30 mean – 2005-9 mean). Scenario C decreases CH4 by 540 ppb relative to CLE 2030, by 260 ppb relative to CLE 2005, and roughly stabilizes surface O3 despite 5 Tg N yr-1 increase in anthropogenic NOx emissions.
4. Future Methane Control Scenarios
Methane emissions in MOZART-2
SPATIAL DISTRIBUTION
Anthropogenic CH4 contributes: ~50 Tg (~15%) to tropospheric O3 burden ~5 ppbv to surface O3
LINEARITY
Ch
ang
e in
O3
bu
rden
(T
g)
Change in anthropogenic CH4 emissions (Tg yr-1)
MOZART-2 (this work; West et al., 2006)TM3 [Dentener et al., 2005]GISS [Shindell et al., 2005GEOS-CHEM [Fiore et al., 2002]IPCC TAR [Prather et al., 2001]
X
Standard (1990s)
CLE (2005)
CLE (2030)
Simulations Idealized Future
Anthrop. 261 332 428
Biogenic* 214 222 222
Biomass Burning
72 23 23
Total 547 577 673
*Biogenic includes wetlands, oceans, and termites
5. Conclusions
CLE A B C
0.2
0.1
0.0
-0.2
-0.1 OZONEMETHANE
W m
-2
+0.16 Net Forcing
+0.080.00 -0.08
Radiative forcing from 2005 to 2030We calculate CH4 forcing from an analytical expression [Ramaswamy et al., 2001] and O3 forcing with the GFDL AM2 radiative transfer model [Freidenreich and Ramswamy, 1999; Schwarzkopf and Ramaswamy, 1999; GFDL GAMDT, 2004]
Annual Mean Daily Max 8-hr Ozone (ppbv)
02468
1012141618
DJF MAM JJA SON
USA
00.5
11.5
22.5
33.5
44.5
DJF MAM JJA SON
Europe
0
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DJF MAM JJA SON
CLE2005
CLE2030
A2030
B2030
C20300
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20
25
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DJF MAM JJA SON
South Asia
Global anthropogenic CH4 emissions decreased uniformly by 30%
Simulation (1) - Base
TIME SCALE
Nearing a new steady-state after 30 years
Anthrop. NOx increases by 5.3 Tg N yr-1 (+19%)Anthrop. CO decreases by 44 Tg CO yr-1 (-10%)Anthrop. NMVOC increase by 3 Tg C yr-1 (+3%)
EMISSIONS
GLOBAL ANNUAL MEAN RESULTS
IMPACTS ON CLIMATE
IMPACTS ON AIR QUALITY
Percentage of model grid box-days where daily max 8-hour O3 exceeds 70 ppbv by season and region
Change in daily max 8-hour O3 (scenario B – CLE) in the season with max occurrences above 70 ppbv
• Spatial pattern of O3 response is largely independent of CH4 source location, but depends strongly on NOx distribution
• Magnitude of the O3 response is approximately linear with reductions in anthropogenic CH4 emissions (~0.1 Tg tropospheric O3 per Tg yr-1 anthropogenic CH4 reduced)
• O3 decrease from CH4 controls is typically maximum near the middle of the total O3 distribution, (e.g. 40-70 ppbv total O3), but also extends to the high end of the distribution in NOx-saturated conditions (Los Angeles, Houston)
• Future CH4 controls relative to the CLE baseline (scenarios B or C) would offset the projected positive climate forcing and reduce the incidence of high-O3 events in all regions, even improving air quality in Europe relative to 2005.
CLE 2030 daily max 8-hr average O3 (ppbv)
Each point represents one daily maximum 8-hour average O3 value in one model grid cellfrom Jun 1 to Aug 31Composite maximum difference in U.S. daily
max 8-hour mean ozone JJA (year 30)
-8 -7 -6 -5 -4 -3 -2 ppbv
Locations with NOx-saturated chemistry
-1.75 -1.50 -1.25 -1.00 -0.75 -0.50 -0.25 ppbv
Decrease in global July mean O3 at simulation year 11
Emission reduction in AsiaGlobally uniformemission reduction
Percentage difference (Asia – uniform)/ Asia
-10 -5 -1 1 5 10 20 30 40 %
Enhanced effectin source region
<10% other NH source regions<5% rest of NH<1% most of SH
Surface O3 (ppbv)Tropospheric O3
Burden (Tg) < 0.3 0.8 1.4 1.9 2.5
Surface NOx emissions 2030:2005 ratio
0 5 10 25 50 75 100 125 150 175 mW m-2
TROPOSPHERIC OZONE
Surface CH4 (ppb)
CLE
B
C
A
0
2
4
6
8
10
12
DJF MAM JJA SON
Africa
Difference: Scenario B 2030 – CLE 2030
Methane contributionincreases with total O3 until ~60-80 ppbv then saturates0 50 100 150 200
2
0
-2
-4
-6
EUROPE JJA
Mean of 10 ppb bins
2
0
-2
-4
-60 50 100 150 200
AFRICA JJA
0 50 100 150 200
SOUTH ASIA MAM2
0
-2
-4
-6
Max impact from CH4 at 40-60 ppbv total O3
Increased incidence of O3 > 70 ppbv in CLE from 2005 to 2030 occurs in all regions and seasonsAggressive CH4 controls (B and C) more than offset projected increases in high-O3 events in Europe
Max CH4 impact at ~40-70 ppbv total O3, plus some high-O3 events
Aggressive CH4 reductions (scenarios B and C) offset the positive forcing predicted under the CLE baseline
EMEP (2005), EMEP/CCC-Report 1/2005, Norwegian Institute for Air Research, Norway.Horowitz, L.W. et al. (2003), J. Geophys. Res., 108, 4784.Prather, M.J. et al. (2001) in Climate Change 2001, ed. J.T. Houghton et al., pp. 239-287, Cambridge University Press.Ramaswamy, V. et al. (2001) in Climate Change 2001, ed. J.T. Houghton et al., pp. 349-416, Cambridge University Press.Schwarzkopf, M.D. and V. Ramaswamy (1999) J. Geophys. Res., 104, 9467-9488.
Shindell et al. (2005) Geophys. Res. Lett., 32, L040803.Wang, J.S. et al. (2004) Global Biogeochem. Cycles, 18, GB3011. West and Fiore (2005) Environ. Sci. Technol, 39, 4685-4691.West et al. (2006) Proc Natl Acad. Sci., 103, 3988-3993.van der Werf, G.R. et al. (2003) Global Change Biol., 9, 547-562.
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Surface Methane (ppb)
Tropospheric O3 Burden (Tg)
0 5 10 15 20 25 30
Difference: CLE 2030 – CLE 2005
Largest increases occur over SE Asia (up to 20 ppbv).
Growth in ship NOx emissions raises O3 by a few ppbv over the N. Atlantic (see above for NOx emission changes)
Surface O3 at N tropics and mid-latitudes shows largest response to CH4 controls; largest decreases occur in high-NOx areas
Black boxes indicate regions analyzed below
CLE 2030
Change in zonal mean O3 (year 30)
-5 -4 -3 -2 -1 0 % -2.0 -1.5 -1.0 -0.5 0.0 ppb
Latitude
Absolute change Percentage change
-50 0 50 -50 0 50
200
400
600
800
200
400
600
800
Pre
ssu
re
USA JJA
0 50 100 150 200
2
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-4
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Color-coded by U.S. regionNE SE SW NW
