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Improving Air Quality Forecasting with GOES Total Column Ozone Assimilation

This study explores the impact of improved vertical resolution in NAM-CMAQ on GOES Total Column Ozone assimilation, as well as the use of climatological ozone to improve lateral boundary conditions in NAM-CMAQ. The results show improved accuracy in surface ozone forecasts and provide valuable insights for future air quality forecasting capabilities.

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Improving Air Quality Forecasting with GOES Total Column Ozone Assimilation

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  1. Implementation of GOES Total Column Ozone Assimilation within NAM-CMAQ to improve Operational Air Quality Forecasting capabilities R. Bradley Pierce (NOAA/NESDIS/STAR) Todd Schaack, Allen Lenzen, (UW-Madison, CIMSS) Pius Lee (NOAA/OAR/ARL) 10th JCSDA Workshop on Satellite Data Assimilation,  College Park, MD, October 10-12, 2012

  2. Directions (9th JCSDA Workshop) • Work with the NOAA Air Resources Lab (ARL) and the National Air Quality Forecasting Capability (NAQFC) team to test impact of improved vertical resolution in NAM-CMAQ • Coarse vertical resolution within Operational NAM-CMAQ leads to increased biases in surface ozone over the inter-mountain west Work with the NASA Air Quality Applied Science Team (AQAST) to test the use of climatological ozone P-L improve the GFS tropospheric distributions and provide time-dependent lateral boundary conditions to NAM-CMAQ Outline • Impact of improved vertical resolution in NAM-CMAQ on GOES Total Column Ozone assimilation • Improved Lateral Boundary Conditions for NAM-CMAQ AQ forecasts • Next Steps: Assimilation of hyperspectral O3 retrievals and radiances within GDAS • Summary

  3. Impact of improved vertical resolution in NAM-CMAQ • Focus on 56 level “tightly coupled” NAM-CMAQ/GSI GOES Total Column Ozone (TCO) experiments during July 2011* • Addresses impact of coarse vertical resolution within Operational NAM-CMAQ • Facilitates alignment with real-time parallel runs using NMMB being conducted by NAQFC • Allows use of NASA DISCOVER-AQ airborne insitu data and ozonesondes for validation • NAM-CMAQ/GSI experiments began on June 22th, 2011 and extend to July 31th, 2011 with June 22-June 30st, 2011 being treated as a spin-up period. • CMAQ version 4.6 with adjusted surface deposition and including wildfire emissions from the U.S. Forest Service’s Pacific Wildland Fire Sciences Laboratory BLUESKY framework * Based on discussions with Ivanka Stajner (NWS/OST Program Manager for NAQFC) following the 9th JCSDA workshop

  4. July 2011 56 level NMMB-CMAQ/GSI GOES Total Column Ozone (TCO) assimilation experiments • Conducted using the following configurations: • loose and tight coupling of the CMAQ vertical coordinate with the NMMB vertical grid • with and without GFS Lateral Boundary Conditions (LBC) • With and without GOES TCO assimilation • with and without using GFS ozone distributions to constrain the upper troposphere/lower stratosphere within the CMAQ model domain • These experiments were used to determine the optimal way to combine the NAM-CMAQ and GFS ozone distributions to obtain the best background for GOES TCO assimilation within GSI. • Cycling experiments used GOES East and GOES West TCO with bias correction obtained from co-located GOES/OMI TCO measurements • Cycling experiments used updated ozone background error covariances that combine NMMB-CMAQ background errors (NMC method) with default GFS

  5. Baseline: Tightly coupled 56 level NMMB-CMAQ/ No GOES TCO assimilation/static LBC NMMB-CMAQ significantlyunderestimates ozone mixing ratios and variability above 300mb and shows a relatively poor correlation (r=0.51) with the DISCOVER-AQ ozonesonde measurements. CMAQ Ozone Static LBC

  6. GFS LBC: Tightly coupled 56 level NMMB-CMAQ/ No GOES TCO assimilation/GFS LBC NMMB-CMAQ significantly overestimates ozone mixing ratios between 300-100mb and variability below 200mb but shows an improved correlation (r=0.75) with the DISCOVER-AQ ozonesonde measurements. CMAQ Ozone GFS LBC

  7. GOES TCO: Tightly coupled 56 level NMMB-CMAQ/ With GOES TCO assimilation/GFS LBC. NMMB-CMAQ stilloverestimates ozone mixing ratios between 300-100mb and variability below 200mb GSI GOES TCO Assimilation GFS Ozone CMAQ Ozone GFS LBC

  8. GFS: GFS UT/LS high biases (~30%) are significantly less then NMMB-CMAQ when GFS LBC are used. This points to an issue with NMMB-CMAQ UT/LS ozone transport even with 56 level tightly coupled framework. Possibly due to diffusive nature of vertical advection and sharp gradient in UT/LS. GFS Ozone

  9. GFS UT/LS: Tightly coupled 56 level NMMB-CMAQ/ With GOES TCO assimilation/GFS LBC/GFS UT/LS Constraining NMMB-CMAQ with GFS UT/LS ozone mixing ratios reduces biases and variability below 200mb and significantly improves correlation (r=0.95) with the DISCOVER-AQ ozonesonde measurements. GSI GOES TCO Assimilation GFS Ozone GFS UT/LS CMAQ Ozone GFS LBC

  10. Improved Lateral Boundary Conditions for Operational NAM-CMAQ AQ forecasts* • Lin Zhang (Harvard) provided GEOS-Chemmodel output for July 2011 and Meiyun Lin (Princeton) provided annual GFDL AM3 model output for 2010 • 3hr averaged 3D ozone production rate and loss frequency, surface deposition • 3hr 3D cloud fraction, optical depths, temperature • Monthly mean 3D merged GFS (stratosphere) + GEOS-CHEM (troposphere) ozone PL was developed for use in GFS ozone physics module which was adapted for inclusion of 3D O3 P-L. • July 2011 GDAS cycling experiments conducted using default GFS O3 PL (Baseline) and with 3D diurnally varying merged GFS/GEOS-CHEM O3 PL • Same approach could be used for implementation of CO2, CH4, N2O, and CO prediction within GFS thereby aligning GFS with CRTM/GSI development *Funded through NASA Air Quality Applied Science Team (AQAST) FY12 Tiger team to support JCSDA hyperspectral (AIRS, IASI, CrIS) ozone assimilation (retrieval and radiance )

  11. Default GFS July O3 PL Tropospheric O3 Production maximum at 700mb/70N is unrealistic Tropospheric O3 Loss uniform below 700mb with maximum at 70N is unrealistic

  12. July 2011 3D merged GFS + GEOS-CHEM O3 PL Tropospheric O3 Production maximum at surface over NH industrial regions (30-50N) is realistic Tropospheric O3 Loss maximum at surface over subtropical NH water vapor (and OH) maximum is realistic

  13. GDAS surface O3 July 2011 3D Diurnal O3 PL Default (Control)

  14. GDAS Control UT/LS high biases (~30%) and tropospheric low biases compared to DISCOVER-AQ ozonesondes. Underestimate in UT/LS and PBL variability. Default O3 PL

  15. GDAS 3D Diurnal O3 PL Slight reduction in UT/LS high biases (~20%) and significant reduction in PBL bias with improved PBL variability compared to DISCOVER-AQ ozonesondes. Default O3 PL 3D Diurnal O3 PL

  16. Anomaly Correlation die off curve at 500 hPa 1 July 2011 – 31 July 2011 Northern Hemisphere Southern Hemisphere FIX2=3D Diurnal O3 PL No statistically significant differences in NH or SH 500hPa 0-5 day Height FX at the 95% confidence level.

  17. Global Temperature Biases 1 July 2011 – 31 July 2011 FIX2=3D Diurnal O3 PL Increase in cold bias at 50hPa and decrease in 10hPa warm bias in 3D diurnal O3 PL experiment (no significant changes below 200mb)

  18. Global and Tropical 50hPa Temperature Bias Drop-off 1 July 2011 – 31 July 2011 Global Tropics FIX2=3D Diurnal O3 PL Statistically significant increase in global 50hPa Temperature cold bias largely explained by increased tropical cold bias (3D diurnal O3 PL worse then Control)

  19. Global and SH 10hPa Temperature Bias Drop-off 1 July 2011 – 31 July 2011 Southern Hemisphere Global FIX2=3D Diurnal O3 PL Statistically significant decrease in global 10hPa Temperature warm bias largely explained by decreased SH warm bias (3D diurnal O3 PL better then Control)

  20. Next Steps: Assimilation of hyperspectral O3 retrievals and radiances within GDAS • Assimilation of ozone measurements will consider both operational ozone retrievals and assimilation of selected channels influenced by ozone absorption (980-1080 cm-1) • Assimilation of the ozone retrievals will include application of retrieval averaging kernels • to the GFS first guess within the observation operator AIRS instrument O3 sensitivity functions GDAS 3D Diurnal O3 PL

  21. Summary • July 2011 NMMB-CMAQ/GFS GOES TCO experiments show that it is necessary to use GFS constraints in the NMMB-CMAQ UT/LS • UT/LS high biases of ~60% still remain and are 2x larger then GFS biases in this region (CMAQ V4.7.1 and beyond uses PPM vertical advection to limit numerical diffusion which may mitigate this issue) • Mid-tropospheric low biases of ~30% still remain and are comparable to GFS biases in this region (may be due to lack of convective mixing of high PBL ozone into mid-troposphere). • 3D diurnally varying tropospheric O3 Production and Loss has been implemented into GFS and GDAS cycling experiments have been conducted during July 2011. • Results in slight reduction in UT/LS O3 high biases (~20%) and significant reduction in PBL bias with improved PBL variability compared to DISCOVER-AQ ozonesondes. • No statistically significant differences in NH or SH 500hPa 0-5 day Height forecast skill was found but statistically significant increases in 50hPa cold biases and reductions in 10hPa warm biases were found. • These experiments will be used as baseline for assessment of the impact of assimilation of hyperspectral IR O3 radiances and retrievals.

  22. Extra Slides

  23. Summary of Status at 9th JCSDA Workshop (May 24-25, 2011, College Park MD) • Findings • GSI GOES Ozone assimilation experiments during the 2010 NOAA CalNex field experiment showed that assimilation of GOES Total Column Ozone (TCO) can lead to improved representation of upper tropospheric and lower stratospheric ozone within NAM-CMAQ • However, coarse vertical resolution within Operational NAM-CMAQ leads to overestimates in decent of high ozone into the lower troposphere and increased biases in surface ozone over the inter-mountain west • Directions • Work with the NOAA Air Resources Lab (ARL) and the National Air Quality Forecasting Capability (NAQFC) team to test impact of improved vertical resolution in NAM-CMAQ • Work with the NASA Air Quality Applied Science Team (AQAST) to test the use of climatological ozone P-L improve the GFS tropospheric distributions and provide time-dependent lateral boundary conditions to NAM-CMAQ

  24. NMMB-CMAQ S4 benchmarking experiments The 22 level operational NMMB-CMAQ and associated preprocessors (BLUESKY, SMOKE, PREMAQ) from the NCEP Central Operations (NCO) was ported onto the NESDIS S4 computer at UW-Madison and benchmarked with respect to NCO parallel runs (referred to as B1A Fire1 at NCO). The NMMB-CMAQ surface ozone forecast conducted on S4 is in very good agreement with NCO: 99.11% of the S4 48hr surface ozone prediction is within 0.001% of the NCO prediction after 8 days of forecast cycling.

  25. GDAS 3D Diurnal O3 PL Slight reduction in UT/LS high biases (~20%) and significant reduction in PBL bias with improved PBL variability compared to DISCOVER-AQ ozonesondes.

  26. RAQMS explicit O3 PL: MLS stratospheric profile/OMI TCO assimilation GDAS biases with 3D monthly mean diurnal O3 P-L is comparable to RAQMS explicit O3 PL. UT/LS variability is not captured in GDAS. GDAS mid-tropospheric low bias most likely due to lack of convective mixing of high O3 out of continental PBL within GDAS

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