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Evaluation of Satellite NO 2 Columns over U. S. Power Plants using a Regional Atmospheric Chemistry Model Si-Wan Kim ESRL, NOAA and CIRES, U. of Colorado.

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Presentation on theme: "Evaluation of Satellite NO 2 Columns over U. S. Power Plants using a Regional Atmospheric Chemistry Model Si-Wan Kim ESRL, NOAA and CIRES, U. of Colorado."— Presentation transcript:

1 Evaluation of Satellite NO 2 Columns over U. S. Power Plants using a Regional Atmospheric Chemistry Model Si-Wan Kim ESRL, NOAA and CIRES, U. of Colorado Acknowledgements SCIAMACHY Data: A. Heckel, A. Richter, and J. Burrows at Univ. of Bremen OMI Data: J. Gleason at NASA Emission Inventory and WRF-Chem model: G. Frost, S. McKeen, E.-Y. Hsie, M. Trainer, G. Grell and S. Peckham at ESRL, NOAA and CIRES, U. of Colorado Sep 10-12, 2007, Workshop at KNMI

2 1.Background 2. WRF-Chem model 3. Satellite instruments and retrievals 4. NO 2 columns over power plants 5. Conclusions 6. Future Plans Outline

3  Uncertainties in NOx emission inventory (“bottom-up emission”)  Evaluation of estimated NOx emissions with satellite observed NO 2 columns  NOx emissions  NO 2 columns ( Martin et al., 2003, Beirle et al., 2003, Richter et al., 2005, van der A, 2006, Kim et al., 2006… )  For power plants, known NOx emissions (CEMS) --> Accurate model NO 2 columns --> Evaluation of satellite NO 2 observations 1. Background

4 Western USEastern US Background Why Western U.S. ?

5 SCIAMACHYOMI Background Observation of NO 2 Columns by Satellites

6 Background Identification of Sources (Power Plants) North Valmy Intermountain Hunter / Huntington Mohave Navajo Four Corners/ San Juan Cholla/Coronado/ Springerville Bonanza Craig/Hayden Jim Bridger/ Naughton Dave Johnston/ Laramie River Colstrip Reid Gardener

7 Background Identification of Sources (Power Plants) North Valmy Intermountain Hunter / Huntington Mohave Navajo Four Corners/ San Juan Cholla/Coronado/ Springerville Bonanza Craig/Hayden Jim Bridger/ Naughton Dave Johnston/ Laramie River Colstrip Reid Gardener

8  Weather Research and Forecasting – Chemistry model (www.wrf-model.org/WG11)www.wrf-model.org/WG11 Simulate chemistry and aerosol online within WRF model Option to simulate coupling among chemistry, aerosol, radiation and clouds.  Various chemical mechanisms (kpp available) and aerosol modules  Various physical packages: PBL, Microphysics, Radiation and Convective parameterizations 2. WRF-Chem Model

9  Period: 2005 Summer  Initial & Boundary Condition: NCEP GFS & Idealized chemical soundings  Emissions : NEI99 updated following CEMS 2005  PBL: YSU Microphysics: WSM5 Radiation: Dudhia shortwave Cumulus parameterization: Grell & Devenyi Land-Surface: Noah  Chemical mechanisms: RADM2, RACM, RACM-ESRL Aerosol: MADE-SORGAM  Advection scheme: Original & Positive Definite WRF-Chem Model Setup

10 WRF-Chem Model Difference due to Chemical Mechanism

11 WRF-Chem Model Four Corners & San Juan Power Plants Difference due to Advection Scheme

12 SCIAMACHY (ENVISAT) Period: March 2002 ~ Resolution: 60 x 30 km 2 Global coverage at the equator: 6 days (due to alternate limb nadir viewing Time: 10:30 LT OMI (EOS-Aura) Period: November 2004 ~ Nadir View Resolution: 13 x 24 km 2 (nominal), 13 x 8 km 2 (zoom-in) Global coverage: 1 day Time: 1:30 LT Sampling Clear Sky (Pixels with Cloud fraction < 0.15) For OMI, 10 < swath mode number < 50 are used. 3. Satellite instruments

13 Satellites  Subtraction of stratospheric NO 2  Vertical sensitivity (AMF, Air Mass Factor) A priori NO 2 profile Aerosols Terrain Height Albedo (Reflectivity) Retrieval Issues: Tropospheric NO 2 columns

14 Satellites  A priori NO 2 profile SCIAMACHY MOZART NO 2 profile SCIAMACHY WRF-Chem NO 2 profile Retrieval Issues (prof1)

15 Satellites  A priori NO 2 profile Retrieval Issues (prof2) AMF-WRFprof AMF-MOZprof

16 Satellites  Aerosols Retrieval Issues (aero1)

17 Satellites  Aerosols Retrieval Issues (aero2) AMF-NoAerosol AMF-EdgarAerosol

18 Satellites Retrieval Issues (terrain)

19 4. NO 2 columns over power plants SCIA Mohave Intermountain Navajo Four Corners/ San Juan * Summer of 2005 WRF OMI WRF Jim Bridger/ Naughton

20 Four Corners (SCIAMACHY) Power plant emissions * 14 day running mean Model chemistry ~7% Model advection ~8% Satellite a priori profile ~6% Satellite aerosol ~3%

21 Four Corners (OMI) Power plant emissions Model Chemistry ~2% Model Advection ~11%

22 Jim Bridger & Naughton Power plant emissions

23 Intermountain Power plant emissions

24 Mohave Power plant emissions

25 Navajo Power plant emissions

26 Name of Plant (size of box: lon.  x lat.  ) Satellite NO 2 columns or Difference (WRF - Satellite) (10 15 molec. cm -2 ) SCIA1 WRF - SCIA1SCIA2WRF - SCIA2OMIWRF - OMI Four Corner/San Juan (2 x1) Jim Bridg./Naught. (2.75 x 2) Intermountain (1.5 x 1) Mohave (1 x 0.788) Navajo (1.5 x 0.625) ( 25%) 0.04 ( 3%) 0.70 ( 53%) 1.41 ( 60%) 1.61 ( 89%) ( 34%) 0.32 ( 29%) 0.88 ( 78%) 1.35 ( 56%) 1.66 ( 93%) ( -5%) ( -6%) ( -23%) ( -6%) 0.17 ( 6%) SCIA1: MOZART NO 2 profile / SCIA2: WRF-Chem NO 2 profile Model is overestimated to SCIA and is underestimated to OMI. However, both satellites show good agreement with model for Four Corners/San Juan power plants. In general, smaller boxes show higher biases for SCIA Summary: Power Plants

27 5. Conclusions * Satellite NO 2 columns agree well with model NO 2 columns over the regions where total NOx emission is dominated by power plants. For small size power plants, however, SCIAMACHY data are higher than the model results, while OMI and the model agree reasonably well, implying that the data frequency and resolution of SCIAMACHY limit the detection of these confined power plants. * Applying positive advection scheme for RACM-ESRL (not done yet) may reduce discrepancy between SCIAMACHY and the model and increase discrepancy between OMI and the model. * Inclusion of hourly and daily varying power plant emissions may reduce the discrepancy between model and satellites. * The analysis can be extended to urban and highway emissions, which was known to be much more uncertain than those from power plants.

28 * Include daily variation of emissions from Four Corners and San Juan Power Plants: reductions in weekends and holidays by 25% 6. Future Plans


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