Crawford Sarp

NASA’s Research Program in Tropospheric Chemistry: How are Human Influences Changing Earth’s Atmosphere?

Emission (NOx, CO, Hydrocarbons)

Transformation/Oxidation (O3, OH, CH2O, HO2, RO2)

Removal (HNO3, H2O2, ROOH)

Global NOx Sources (teragrams of nitrogen per year) Source Fossil Fuels Biomass Burning Soil Emissions Aircraft Lightning

Magnitude (uncertainty) 22 (13-31) 8 (3-15) 7 (4-12) 0.85 (0.5-1) 5 (2-20)

Global Hydrocarbon Sources (teragrams of carbon per year) Source Possible Range Fossil Fuels 46-95 Biomass Burning 25-80 Emission from Foliage 800-1500 Soils/Oceans/Grasslands 15-30

Emission (NOx, CO, Hydrocarbons)

Transformation/Oxidation (O3, OH, CH2O, HO2, RO2)

Removal (HNO3, H2O2, ROOH)

Tropospheric Ozone Significance: Environmentally Important: Ozone is a pollutant adversely impacting health and agriculture Chemically Important: Ozone initiates the oxidation cycles responsible for removing most polluting gases from the atmosphere. These oxidation cycles also influence ozone itself. Climatically Important: Ozone influences climate directly as a greenhouse gas and is most important in the upper troposphere where temperatures are cold. Ozone exerts an indirect influence through the oxidation of other greenhouse gases.

Emission (NOx, CO, Hydrocarbons)

Transformation/Oxidation (O3, OH, CH2O, HO2, RO2)

Removal (HNO3, H2O2, ROOH)

Removal by precipitation

XO Removal by precipitation

O3

Multi-step process Multi-step process

X HNO3

NH3

NO2 O(3P) N2,O2

O2

OH H2 O CO

O(1D) hv

hv H

H2 O2 Removal by precipitation

HO2

H2SO4

NH2

CH3CCl3 HX

O3

NO

HCl

Removal by preexisting particles or nucleation

SO2

HSO3

Multi-step process

Multi-step process

SO2

CH3SCH3 CXHY Multi-step process H2

CO

NO O2

H2 O HO2

Emission (NOx, CO, Hydrocarbons)

Transformation/Oxidation (O3, OH, CH2O, HO2, RO2)

Removal (HNO3, H2O2, ROOH)

Airborne Field Campaign Strategy: Maximize the value of satellite  data for improving models of atmospheric composition and climate   Satellites: mainly column amounts  •O3, CO, NO2, HCHO •  Aerosol optical depth, properties

Aircraft: DC­8, P­3B, B200

• Comprehensive in situ chemical and aerosol          measurements • Lidar remote sensing of ozone, water vapor    and aerosol optical properties   Solar radiation measurements •  

Global and Regional Models

•  Source­receptor relationships for pollution •  Inverse modeling for estimating emissions •  Aerosol radiative forcing •  Detailed chemical processing

Calibration and Validation Retrieval development Correlative information Small scale structure and processes

Model error characterization Data assimilation Diagnostic studies

NASA satellite observations of Atmospheric Composition Ozone (O3): Aura-MLS, Aura-TES Carbon Monoxide (CO): Terra-MOPITT, Aqua-AIRS, Aura-TES Nitrogen Dioxide (NO2): Aura-OMI Formaldehyde (CH2O): Aura-OMI Aerosols: Terra-MODIS and MISR, Aqua-MODIS, CALIPSO, Glory-APS, Aura-OMI

Terra 10:30

OMI & MLS: Global Tropospheric Ozone Residual

OMI & MLS produce a tropospheric ozone product by subtracting the MLS stratospheric ozone from OMI column ozone. This can be compared to the more sparse but direct observations from TES

*Notice that largest ozone enhancements are downwind of source regions Mark Schoeberl, NASA GSFC

CO observations from MOPITT and AIRS: Tracing pollution transport from combustion sources Strengths: -Atmospheric lifetime of ~2 months is ideal for observing long-range transport which takes place in mid-troposphere. -Excellent detection of enhanced CO from fires -4.2 µ m thermal emission allows detection both day and night Limitations: -Sensitivity limited mainly to middle troposphere -No significant vertical resolution

Future observations aim to provide additional detection for 2.3 µ m channel Strengths: -Solar reflection at 2.3 µ m will be sensitive to total column extending down to the surface -Information on surface concentrations may be derived in 20 combination with 4.6 µ m observations 2.3µm Avg. Kernel

Altitude (km)

Limitations: -Solar reflection limits detection to daytime mainly over land

10

Avg. CO profile Los Angeles (July 2004)

4.6µm Avg. Kernel

MOPITT Seasonal Average CO (850mb) 0 0

50

100 150 CO, ppb

200

250

NO2 observations from OMI: High resolution information on anthropogenic emissions

Strengths: -Atmospheric NO2 abundance is weighted toward surface, therefore column measurement can yield useful information on variability in surface emissions -Atmospheric lifetime of NO2 is less than one day near the surface, therefore observed enhancements are in close proximity to sources. Limitations: -Stratospheric abundance of NO2 must be subtracted to give a tropospheric residual (similar to ozone), however, tropospheric NO2 dominates the column in polluted areas. -Partitioning between NO2 and NO must be assessed to estimate total NOx, although NO2 typically constitutes ~80% of nearsurface NOx -Emission of NOx undergoes large diurnal variability

OMI NO2: Beijing Olympics

Bryan Duncan, NASA GSFC

Beijing Olympics: Pollution Reduction Efforts

x1015 molec/cm2

OMI Tropospheric NO2 – around Beijing, China

Month A 50% reduction in NO2!

A 20-40% reduction in SO2!

Bryan Duncan, NASA GSFC

Formaldehyde observations from OMI: Oxidation of biogenic and other hydrocarbon emissions Strengths: -Atmospheric CH2O abundance is weighted toward surface with no significant stratospheric burden -Oxidation of most hydrocarbons result in CH2O, therefore it is an excellent proxy for the integrated influence of hydrocarbons on ozone photochemistry Limitations: -CH2O is not directly emitted, but rather is a byproduct of photochemistry. With a short lifetime (hours), it undergoes large changes throughout the day. -Atmospheric lifetime of CH2O is less than one day, observed enhancements occur at variable distances from hydrocarbon sources, depending on their atmospheric lifetime.

NASA Tropospheric Chemistry Field Campaigns (1983-2008)

INTEX-B Flights Provide Science-Focused Validation Opportunities: DC-8 Flight 16 from Anchorage

MLS TES-L

Asian pollution

Multiple satellite tracks are examined for validation

Large concentrations of ozone are associated 12 300 with high CO suggesting Asian pollution

DIAL O3 (E. Browell, NASA LaRC)

10

250

8

200

6

150

4

100

2

50

0

0

CO (ppbv)

Altitude (km)

Large concentrations of ozone in the Pacific troposphere

CO prediction from the RAQMS model (R. B. Pierce, NASA LaRC)

DACOM CO (G. Sachse and G. Diskin, NASA LaRC)

OMI NO2 Tropospheric Column Compared with GEOS-Chem Asian NOx anthropogenic emissions for the year 2000

2 x 2000 Asian NOx emissions

OMI NO2 tropospheric column observations suggest a factor of 2 increase of Asian anthropogenic NOx emissions from 2000 to 2006.

D. Jacob, Harvard

Satellite observations reveal increasing Asian NO2 emissions

Transport of Asian Ozone and its Precursors The mean Asian ozone, CO, NOx, and PAN enhancements at 800 hPa for INTEX-B

Ozone

CO

NOx

PAN

Latitudinal distribution of NO2 and PAN at 1.5 -5 km

NO2

PAN

Asian Ozone Enhancement over the U.S. Surface for INTEX-B CO and O3 measurements at MBO for INTEX-B 140 ± 14

Mean O3 enhancements from Asian emissions over the U.S. surface

122 ± 10 36 ± 6

54 ± 10

53 ± 8 9±2

1 – 5 ppbv

D. Jacob, Harvard

HOW DO AIRBORNE FIELD CAMPAIGNS AFFECT POLICY? Satellites Models

2 yrs

5 yrs 10 yrs

Aircraft Information synthesis Improved knowledge; publications in scientific journals Improved model predictions

Summary assessments for policymakers:  Intergovernmental Panel on Climate Change Arctic Council UNEP Hemispheric Transport of Pollution Assessment

Better­informed decisions to protect the environment

Contrasting Conditions along a Frontal Zone 5

P-3B Flight 19

Altitude (km)

4 3 2 1 0 100

150

200

250

300 350 400 CO (ppbv)

450

500

550

600

10

10 40

Clouds may bias satellite estimates of pollution in Asian outflow… observations in cloudy areas are needed

DC-8 P-3B

9

30

25

8

8

7

7

Altitude (km)

Altitude (km)

35

6 5 4

DC-8 P-3B

9

6 5 4

3

3

2

2

1

1

20

15

0

0

100

200

300

CO (ppbv)

10

10-11 km

400

0

0

10 20 30 40 50 60 70 80 90 100

Relative Humidity (percent)

In Cloud Above Cloud Clear Below Cloud

9-10 km 8-9 km 7-8 km 6-7 km 5-6 km 4-5 km

Jan. 27 - Feb. 2, 2003 (1 week)

3-4 km 2-3 km 1-2 km 0-1 km 0

100

200

CO (ppbv)

300

Median CO (ppbv) Enhancement in Cloudy Regions Clear Cloudy Enhancement 1-5 km 5-11 km

135 101

178 116

32% 15%

Feb. 1 - 25, 2004 (3.5 weeks)

Air quality concerns overlap with short-lived, non-CO2 climate forcing…

Relative contributions to observed Arctic warming over the last century

(IPCC Fourth Assessment Report)

Courtesy of Trish Quinn, NOAA Note: uncertainties are large

Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) conducted flights during Spring (Arctic Haze) and Summer (Boreal Fires) DC-8

P-3B

B200

Terra 10:30

LIDAR INSTRUMENTS ON THE AIRCRAFT OBSERVE ARCTIC HAZE  FROM THE SURFACE TO 30,000 FEET Other instruments on the aircraft pinpoint the origin of this haze Iqaluit­Fairbanks DC­8 transit, April 9; Yellow­green colors indicate Arctic haze Asia

Europe

Fires

North America

Johnathan Hair, NASA/LaRC

Long-range transport from mid-latitudes into the Arctic results in an aerosol haze (in blue) that is mixed throughout the troposphere.

cloud cloud

High Spectral Resolution Lidar Observations of Arctic Haze from the NASA B200 aircraft

Intense aerosol plumes originating from fires were superimposed on the background arctic haze…how important are they? Aerosol Extinction 10 0.00

0.05

0.10 3

Black Carbon (µg/m )

Altitude (km)

8

6

4

2 Median th

th

10 and 90 Percentile

0 0

20 40 60 80 -1 Aerosol Extinction (Mm )

100

Anomalies in fire counts from MODIS and Carbon Monoxide from MOPITT corroborate unusually strong fire emissions over Siberia in April 2008.

Comparison of CALIPSO satellite observations and models suggests that transport of aerosols to the Eastern Asia (110E – 130E) arctic from Siberian CALIPSO (observations) fires is too strong in models . Sharp gradient observed by CALIPSO not seen in model predictions. GMAO (model)

RAQMS (model)

Preliminary model results for carbon monoxide indicate that fire emissions are overestimated by factors of 2 to 3. For aerosols, scavenging and removal by precipitation is an additional concern requiring attention.

Closing points: ARCTAS observations show a larger than expected contribution from fire emissions in Spring, although this may not be inconsistent with recent trends in boreal fires. Models appear to do a reasonable job of reproducing observed carbon monoxide distributions, but require estimated fire emissions to be reduced by factors of 2 to 3. Scavenging is an additional factor critical to understanding aerosol impacts. What fraction of the aerosol transported to the arctic is ultimately deposited to the snowpack? 25

20

Russia Canada and Alaska

15

10

5

0 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005

Area Burned over Time (M ha)

UV DIAL Ozone Depletion Events (ODE) 17 April 2008 Extending UV DIAL measurements near surface

NO Low Ozone Event measured by: UV-DIAL or NCAR CLD Low Ozone Event measured by: UV-DIAL or NCAR CLD

UV DIAL Ozone Depletion Events (ODE) 8 April 2008 Extending UV DIAL measurements near surface

NO Low Ozone Event measured by: UV-DIAL or NCAR CLD Low Ozone Event measured by: UV-DIAL or NCAR CLD

5/1/2006 Flight (RF 06)

J. Jimenez, CU-Boulder

• Pre-flight modeling showed Asian influenced air mass off coast of Northwest U.S. – Flight plan chosen to intercept it

• Pollution seen in layer at 20,000 ft early and late in flight

5/1/2006 Flight AMS observes high SO4 loading with some Organics

E. Apel et al. (TOGA)  MTBE as tracer for Asian pollution MTBE used in gasoline in Asia, no longer in U.S. gas This appears to be best Asian transport event J. Jimenez, CU-Boulder

Forecast Evaluation - May 4 - DC8

MOZART Forecast CO along flight track (Fx initialized 0502 12UTC)

MOZART Forecast CO interpolated to flight track compared to preliminary data from DACOM*

* Data from Glen Sachse, NASA Langley

05/04 12Z Forecast: Valid for 05/05 18-24Z 18Z: 700 hPa

24Z: 700 hPa

200

300 400 500 600 700 800 900 1000 16:48

18:00

19:12

20:24

21:36

22:48

00:00

01:12

02:24

L. Emmons, NCAR

5/ 5 00Z fo re ca st

Friday, 5/5, 18Z

CO

CO 1 4 3

1

2

3

4

8000 7000

2

6000 5000 4000 3000 2000 1000 0 16:48

GEOS-Chem and FLEXPART forecasts were very similar to MOZART for this flight…

18:00

19:12

20:24

21:36

22:48

00:00

01:12

8000 7000 6000 5000 4000 3000 2000 1000 0 16:48

18:00

19:12

20:24

21:36

22:48

00:00

01:12

02:24

02:24

7

Altitude (km)

6 5 4 3 2 1 0 100 125 150 175 200

125 150 175 200

125 150 175 200

125 150 175 200

125 150 175 200

T. Campos, NCAR

Carbon Monoxide (ppbv) 7

Altitude (km)

6 5 4 3 2 1 0

25

50

75

100 125

50

75

100 125

50

75

100 125

Ozone (ppbv)

50

75

100 125

50

75

100 125

A. Weinheimer, NCAR

7

Altitude (km)

6 5 4 3 2 1 0

0

250 500 750 1000

250 500 750 1000

250 500 750 1000

NOy (pptv)

250 500 750 1000

250 500 750 1000

A. Weinheimer, NCAR

7

Altitude (km)

6 5 4 3 2 1 0

0 100 200 300 400 500 100 200 300 400 500 100 200 300 400 500 100 200 300 400 500 100 200 300 400 500

PAN (pptv)

F. Flocke, NCAR

The 2004 Alaska Fires

MOPITT 700 hPa CO mixing ratio for the period 15-23 July, 2004, during the INTEX-A field campaign. The intense wildfires in Alaska produced plumes of carbon monoxide pollution that can be traced across North America and the Atlantic Ocean. . David Edwards, NCAR

MOPITT improves estimates for boreal fire emissions and their impact on CO and O3

CO

O3 Pfister et al., GRL, 2005

• Inverse modeling of MOPITT observations using the MOZART CTM showed that the fires emitted about as much CO as did humanrelated activities in the continental USA during the same time period, about 30 Tg CO June-August • Because of the wildfires, ground-level concentrations of O3 increased by 25% or more in parts of the northern continental USA and by 10% as far away as Europe

Enhancements to CO column and surface O3 due to fires, July 15-25, 2004.  . David Edwards, NCAR

Long-range transport of smoke affects air quality Comparison of MODIS and GOCART MODIS AOT 550 nm 200407

•

Pollutants from forest fires (e.g., aerosol particles and ozone) can be transported long distances, affecting surface air quality downwind.

•

In July 2004, large forest fires occurred in Alaska and western Canada. Smoke aerosols were transported across Canada and to large areas of continental U.S., affecting regional air quality.

•

Event was observed by MODIS and simulated by the GOCART model, which showed a similar pattern and intensity for aerosol optical thickness.

GOCART AOT 550 nm 200407

Mian Chin, NASA GSFC

Violations of National Ambient Air Quality Standards (NAAQS) are primarily related to ozone and fine particulate matter.

Ozone concentrations in ppm, 2007 (fourth highest daily max 8-hour concentration).

Annual average PM2.5 concentrations in µg/m3, 2007

* Yellow and Red symbols represent levels in violation of NAAQS Taken from National Air Quality-Status and Trends through 2007 (http://www.epa.gov/airtrends/2008/)

Aerosols Significance: Environmentally Important: Aerosols adversely impact health, reduce visibility, and acidify precipitation Chemically Important: Aerosols are critical to atmospheric removal processes. Climatically Important: Aerosols influence Earth’s energy balance directly through the scattering and absorption of radiation as well as indirectly through modification of clouds (e.g., distribution and optical properties).

URGENT NEED TO BETTER UNDERSTAND CHANGES IN THE ARCTIC ATMOSPHERE THE ARCTIC IS A BEACON OF GLOBAL  CHANGE •

Receptor and accumulator of pollution from  northern mid­latitudes continents: arctic haze,  mercury,…

•

Increasing forest fires in Siberia, Canada, Alaska  blanket large areas with smoke

•

Rapid warming over the past decades – faster  than anywhere else on Earth

•

Arctic haze and other pollution may be an  important contributor to the warming, with  complicated feedbacks

Our goal is to test and improve the models used to  predict changes in Arctic pollution and climate

mining pollution transport with aircraft, models, and satellites… DC-8 in situ CO

50 75 100 125 150 175 200 ppbv

GEOS-Chem Column COAIRS 500 mb CO (ascending)

0.5 0.9

1.3

1.7 2.1 2.5 1018 molec/cm2

0

50 100 150 200 250 ppbv

Characteristics of the pollution plume: • Observed at ~4-6 km • Elevated CO, SO4, and HCN • Source could be: • anthropogenic emissions from eastern Asia • biomass burning from southern Jenny A. Fisher [Harvard], Glenn Diskin [LaRC], Juying Warner [UMBC] Siberia

Atmospheric Temperature and Pressure

Tropospheric Photochemistry Key Roles for Ozone: Dominant Source of OH

NOx Partitioning O3

O3

hν

H2O

NO

NO2

hν OH

Tropospheric Photochemistry Key Roles for HOx (OH+HO2): Oxidation of Pollutants OH

.

CO, CH4,

O3 Destruction hν, H2O O3

RH

.

. OH O3

HO2

OH

HO2, CH3O2, RO2 O3

Tropospheric Photochemistry Key Roles for NOx (NO+NO2): Ozone Production

HOx Partitioning

HO2, RO2

NO

NO

NO2

hv O3

HO2

OH

CO

Simplified HOx production and loss scheme RO2

O3 hv

H2O

CH4

OH

NO

CH2O

CH3COCH3 hv

hv OH

NMHC CO, O3

NO

HO2 HO2

RO2

NO2

HNO3

NO, O3

hv hv

H2O2 ROOH

Example of nonlinear chemical behavior…NOx amount for peak ozone production is sensitive to the source strength for radicals (OH, HO2, and RO2).

Simplified HOx production and loss scheme RO2

O3 hv

H2O

CH4

OH

NO

CH2O

CH3COCH3 hv

hv OH

NMHC CO, O3

NO

HO2 HO2

RO2

NO2

HNO3

NO, O3

hv hv

H2O2 ROOH

EXAMPLE of nonlinear chemical behavior…both NOx amount for peak ozone production and peak rate are sensitive to the source strength for radicals (OH, HO2, and RO2).

Tropospheric Ozone Photochemistry O( D) 1

H2O

RO2

CH4

CH3O2

NO2

hν

HO2

OH NMHCs

O3

hν

O2

HO2, CH3O2, RO2

OH CO

HO2

F(O3) = (k[HO2] + k[CH3O2] + k[RO2]) [NO] D(O3) = k[O(1D)][H2O] + k[HO2][O3] + k[OH][O3] Net Ozone Tendency = F(O3) - D(O3)

NO