Evaluation of PM 2.5 in the MERRA Aerosol Reanalysis

Transcription

1 Evaluation of PM 2.5 in the MERRA Aerosol Reanalysis Arlindo da Silva (1) 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 5 th Semi-annual Umd College Park, MD, 4-6 June

2 Overview GEOS-5 at a Glance Model Data assimilation GEOS-5 during DISCOVER-AQ Maryland MERRAero AOT evaluation PM 2.5 evaluation Concluding Remarks 2

3 GEOS-5 Atmospheric Data Assimilation System Near Real-time System

4 GOCART Component Dust Seasalt radius radius Goddard Chemistry, Aerosol, Radiation, and Transport Model [Chin et al. 2002] Sources and sinks for 5 non-interactive species dust sea salt black carbon wind and topographic source, 5 mass bins wind driven source, 5 mass bins anthropogenic and wildfire source, mass hydrophic and hydrophilic Black Carbon Organic Carbon Sulfate hydrophobic hydrophilic hydrophobic hydrophilic Mass organic carbon sulfate anthropogenic, biogenic, and wildfire source, mass hydrophic and hydrophilic anthropogenic and wildfire source of SO2, oxidation to SO4 mass Convective and large scale wet removal Dry deposition (and sedimentation for dust and sea salt) Optics based primarily on OPAC

5 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 logtransformed AOD innovation Error covariance models (Dee and da Silva 1999): Innovation based Maximum likelihood 6

6 Observational Bias Original MODIS AOD Bias Corrected AOD

7 GEOS-5/GOCART Forecasts Global 5-day chemical forecasts customized for each campaign O3, aerosols, CO, CO 2, SO 2 Resolution: Nomally 25 km Driven by real-time biomass emissions from MODIS Aerosols interacts with circulation through radiation CO Smoke SO 4

8 GEOS-5 During D-AQ Maryland July

9 HSRL Extinction Profiles 10

10 Revised GEOS-5 PBL Height 11

11 AERONET DRAGON Stations 12

12 AOD / PM 2.5 Challenges AOD assimilation constrains column mass as long as mass extinction efficiency is OK Joint AOD & PM 2.5 assimilation requires unbiased observing system Accurate PM2.5 determination still depends on Speciation Vertical structure 13

13 PM 2.5 at MDE Stations 14

14 MERRAero Overview Model Feature Aerosol Data Assimilation Period Description GEOS-5 Earth Modeling System (w/ GOCART) Constrained by MERRA Meteorology (Replay) Land sees obs. precipitation (like MERRALand) Driven by QFED daily Biomass Emissions Local Displacement Ensembles (LDE) MODIS reflectances AERONET Calibrated AOD s (Neural Net) Stringent cloud screening 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

15 AERONET Validation 16

16 Annual Mean PM

17 PM 2.5 Data Source EPA s AQS PM 2.5 Local Conditions (88101) Daily means Rural & Suburban Period:

18 PM 2.5 Regional Annual Means 19

19 MERRAero PM 2.5 Bias 20

20 PM 2.5 Regional Climatology 21

21 PM 2.5 Regional Daily Joint p.d.f. 22

22 MERRAero PM 2.5 Correlation 23

23 Status Report While MERRAero produces AOD that is unbiased w.r.t. AERONET, its surface PM 2.5 concentrations have a low bias. erroneous PBL height, missing species, mass extinction efficiencies are likely causes Joint assimilation of AOD/PM 2.5 assimilation cannot proceed until this observation bias issue can be resolved. or else spurious time variability will arise 24

24 Work in progress Examine PM 2.5 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 PM 2.5 EnKF (radiance based) New data types: MISR, VIIRS, OMI, CALIPSO, etc. 25

25 Extra Slides Sulfates, etc. 26

26 PM 2.5 Regional Daily Diff p.d.f. 27

27 GEOS-5 Sulfates (2010) 28

28 SO 2 Lifetime in GEOS-5 29

29 Mass Budget 30

30 Decomposing the Mass Flux 31

31 Annual Carbonaceous Flux Potential Total Mean Flow IAU Eddy 32

32 Annual Sulfate Flux Potential Total Mean Flow IAU Eddy 33