evaluation of pm in the merra aerosol...

Evaluation of PM2.5 in the MERRA Aerosol Reanalysis

Arlindo da Silva(1) Arlindo.daSilva@nasa.gov

Virginie Buchard-Marchant(1,2), Pete Colarco, Ravi Govindaradju(1,3) et al. (1) Global Modeling and Assimilation Office, NASA/GSFC (2) GESTAR (3) Science Systems and Applications Inc.

Air Quality Applied Sciences Team 5th Semi-annual Meeting @ Umd College Park, MD, 4-6 June 2013

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Overview GEOS-5 at a Glance Model Data assimilation

GEOS-5 during DISCOVER-AQ Maryland MERRAero AOT evaluation PM2.5 evaluation

Concluding Remarks 2

GEOS-5 Atmospheric Data Assimilation System

Near Real-time System

GOCART Component

hydrophobic

hydrophilic

hydrophobic

hydrophilic

radi

us

radi

us

Dust

Seasalt

Black Carbon

Organic Carbon

Sulfate

Mass

• Goddard Chemistry, Aerosol, Radiation, and Transport Model [Chin et al. 2002]

• Sources and sinks for 5 non-interactive species

• Convective and large scale wet removal • Dry deposition (and sedimentation for

dust and sea salt) • Optics based primarily on OPAC

dust wind and topographic source, 5 mass bins

sea salt wind driven source, 5 mass bins black carbon anthropogenic and wildfire source, mass

hydrophic and hydrophilic

organic carbon

anthropogenic, biogenic, and wildfire source, mass hydrophic and hydrophilic

sulfate anthropogenic and wildfire source of SO2, oxidation to SO4 mass

Aerosol Data Assimilation Focus on NASA EOS

instruments, MODIS for now

Global, high resolution (1/4 deg) AOD analysis

3D increments by means of Lagrangian Displacement Ensembles (LDE)

Simultaneous estimates of background bias (Dee and da Silva 1998)

Adaptive Statistical Quality Control (Dee et al. 1999): State dependent (adapts to

the error of the day) Background and Buddy

checks based on log-transformed AOD innovation

Error covariance models (Dee and da Silva 1999): Innovation based Maximum likelihood

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Observational Bias Original MODIS AOD Bias Corrected AOD

GEOS-5/GOCART Forecasts

CO

Smoke

SO4

http://gmao.gsfc.nasa.gov/projects/DISCOVER-AQ/

Global 5-day chemical forecasts customized for each campaign O3, aerosols, CO, CO2, SO2

Resolution: Nomally 25 km Driven by real-time biomass

emissions from MODIS Aerosols interacts with

circulation through radiation

GEOS-5 During D-AQ Maryland

9 July 2011

HSRL Extinction Profiles

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Revised GEOS-5 PBL Height

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AERONET “DRAGON” Stations

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AOD / PM2.5 Challenges AOD assimilation

constrains column mass as long as mass extinction

efficiency is OK Accurate PM2.5

determination still depends on Speciation Vertical structure

Joint AOD & PM2.5 assimilation requires unbiased observing system

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PM 2.5 at MDE Stations

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MERRAero Overview Feature Description

Model GEOS-5 Earth Modeling System (w/ GOCART) Constrained by MERRA Meteorology (Replay) Land sees obs. precipitation (like MERRALand) Driven by QFED daily Biomass Emissions

Aerosol Data Assimilation

Local Displacement Ensembles (LDE) MODIS reflectances AERONET Calibrated AOD’s (Neural Net) Stringent cloud screening

Period mid 2002-present (Aqua + Terra)

Resolution Horizontal: nominally 50 km Vertical: 72 layers, top ~85 km

Aerosol Species Dust, sea-salt, sulfates, organic & black carbon 15

AERONET Validation

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Annual Mean PM2.5

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PM2.5 Data Source EPA’s AQS PM2.5 Local Conditions

(88101) Daily means Rural & Suburban Period: 2003-12

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http://www.epa.gov/ttn/airs/airsaqs/

PM2.5 Regional Annual Means

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MERRAero PM2.5 Bias

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PM2.5 Regional Climatology

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PM2.5 Regional Daily Joint p.d.f.

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MERRAero PM2.5 Correlation

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Status Report While MERRAero produces AOD that is

unbiased w.r.t. AERONET, its surface PM2.5 concentrations have a low bias. erroneous PBL height, missing species, mass

extinction efficiencies are likely causes Joint assimilation of AOD/PM2.5

assimilation cannot proceed until this observation bias issue can be resolved. or else spurious time variability will arise

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Work in progress Examine PM2.5 speciation Detailed diagnostic for all DISCOVER-AQ

deployments, other field campaigns On-going model development

Aerosol microphysics (MAM) Include nitrates, SOA treatment Improve emission processes

On-going data assimilation development Statistical observation operator for PM2.5

EnKF (radiance based) New data types: MISR, VIIRS, OMI, CALIPSO, etc.

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Extra Slides

Sulfates, etc.

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PM2.5 Regional Daily Diff p.d.f.

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GEOS-5 Sulfates (2010)

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SO2 Lifetime in GEOS-5

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Mass Budget

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Decomposing the Mass Flux

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Annual Carbonaceous Flux Potential

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Total

Eddy

Mean Flow

IAU

Annual Sulfate Flux Potential

33

Total

Eddy

Mean Flow

IAU