The Regional Atmospheric Measurement Modeling and

Prediction Program (RAMMPP)

Russell Dickerson & Jeff Stehr

CICS September 8, 2010

Image taken from URF Aztec Aircraft.

B. Taubman, B. Doddridge

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ProblemThe eastern US suffers from unsafe levels of ozone (photochemical smog) and fine particulate matter (haze).

BackgroundThe retrieval of AOD from the GOES EAST Aerosol/Smoke Product (GASP)measurements is sensitive to aerosol optical properties such as SSA and surface reflectance. GASP is useful for forecasting PM2.5 (haze) and evaluating models such as CMAQ and WRF-Chem.

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((RRegional egional AAtmospheric tmospheric MMeasurement easurement MModeling & odeling & PPrediction rediction PProgram)rogram) Balanced Theory & Observations

ObservationsSurface:

Shenandoah National Park, VABeltsville, MDGreenbelt, MDPiney Run, MD

AloftCessna 402B AircraftProfilerSondes

Remote (NASA)OMI/TES etc.MOPITT (CO)MODIS (particles)SCIAMACHY

(SO2, NO2, H2CO…)

InputEmissions Inventories

Emissions Models

(Chem Engineering)

MM5/WRFDynamical Model

0.5 to 4-km Resolution

Forecasting

Chem/TransModels

CMAQModularOpen CodeCollaborativew/EPAorWRF-CHEMRegionalLinked met/chem

GOCARTglobal

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Major discoveries from RAMMPP

1. Tropospheric aerosols accelerate ozone (smog) production.

2. The spatial and temporal scale of ozone events are larger and longer than thought because:

• The boundary layer is vented faster than WRF predicts. • Reservoir species sequester and re-release NOx. • NOx reductions are more effective than expected. • Emissions inventories are too high for NOx.

3. Particles become fewer, larger, and darker above the PBL.

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CASTNET & NADP Sites in Beltsville, MD

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MDE/Howard University Beltsville Site

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Aztec-F Research AircraftAztec-F Research AircraftGPS Position (°Lat, °Long)

Meteorology (T, RH, Pr, Palt, WS, WD)

Carbon Monoxide (CO)

Ozone (O3)

Sulfur Dioxide (SO2)

Aerosol Optical Properties:Absorption, bap (565 nm)

Scattering, bscat (450,550,700 nm)

Aerosol Particle Size (MetOne)

6 cuts – Range 0.3-1.0 µm

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The new Cessna 402B allows more accurate measurement of aerosol optical properties and chemical composition as well as additional instruments for NO2

and VOC’s.

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General Study Area & Spiral Locations 1992 -2009

Summer observations over eastern North America

• General subsidence (Bermuda High)• Cloud pumping through fair weather cumulus.• Aircraft and satellite observations.

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Trend in American SO2 Emissions

0

5000

10000

15000

20000

25000

30000

35000

1965 1970 1975 1980 1985 1990 1995 2000 2005 2010

Year

Th

ou

sa

nd

s o

f to

ns

pe

r y

ea

r

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Black Carbon or Soot

Soot

Also called black carbon or elemental carbon.

Absorbs solar radiation and warms climate.

Carcinogenic.

• The ambient EC concentration decreases ~50% in the recent 11 years.

13130.0% 1.0% 2.0% 3.0% 4.0% 5.0%

Percent density

Typical westerly

West-southwest

Median particle scattering profiles

0

500

1000

1500

2000

2500

3000

0.00E+00

2.00E-04 4.00E-04 6.00E-04 8.00E-04 1.00E-03 1.20E-03 1.40E-03

Median particle scattering (m-1)

with 25th and 75th percentile bars

Pre

ssu

re d

eriv

ed a

ltit

ud

e (m

)

Typicalwesterly (125)West-Southwest (48)Forest fire 1 (2)

Forest fire 2 (1)

Westerly

AOD ~0.2

WSW

AOD ~ 0.4o Top 0.3% SO2 sources

14http://www.ssd.noaa.gov/PS/FIRE/GASP/loop.html

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Conclusions

1. RAMMPP has generated a long history (up to 17 yr) of trace gas and aerosol properties over the eastern US.

2. Air quality is improving, but still above safe levels for human health and welfare.

3. The Mid-Atlantic region is a good test bed for NOAA’s air quality forecasts and satellite aerosol detection.

4. We will use surface observations and aircraft profiles to evaluate and improve the retrievals from GASP and expand our understanding of atmospheric chemistry and climate.

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Background

The retrieval of AOD from GASP measurements is sensitive to SSA and surface reflectance. GASP is useful for forecasting PM2.5 (haze) and evaluating models such as CMAQ and WRF-Chem.

Testable Hypotheses

1. Black carbon (light-absorbing aerosols) contribute substantially to atmospheric heating over the eastern US.

2. The SSA of aerosols decreases above the PBL because BC has a longer lifetime than sulfates.

3. The SSA of aerosols increases in the summer because sulfate and OA increase while BC emissions remain constant.

4. The absorption efficiency of soot increases with higher concentrations of sulfate and transparent organic material because of coating of soot particles.

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