“An Exceptional Event Concerning Particle Pollution in the Southeast”

1. “An Exceptional Event Concerning Particle Pollution in the Southeast” By: Bill Murphey Chief Meteorologist, Georgia EPD

2. What is an Exceptional Event? • U.S. EPA defines the term "exceptional event" to mean an event that: • Affects air quality; • Is not reasonably controllable or preventable; • Is an event caused by human activity that is unlikely to recur at a particular location or a natural event; and • Is determined by U.S. EPA through the process established in the regulations, 40 CFR Part 50.14. • http://www.in.gov/idem/5498.htm

3. Meteorological Factors and Models used to Determine Air Quality Forecasts • Ambient concentration of pollutant • Synoptic regime • Satellite Imagery (IDEA/MODIS/Fire Imagery) • Surface Meteorology • Upper Air Meteorology (Satellite, Rawinsonde, NWS Models) • Trajectory Analysis (HYSPLIT) • Multiple linear regression model, Decision-tree, Closest Neighbor Models

4. Exceptional Events Examples • Case 1 - Recent PM2.5 smoke episode from Arabia Bay Fire activity in South Georgia (November 12, 2010) • Case 2 – Smoke transported northwestward from Waycross fires in south Georgia (May 22, 2007)

5. Case 1 – Arabia Bay Fire • The Arabia Bay fire, located six to ten miles northwest of Homerville in Clinch County (south Georgia), had burned nearly 3000 acres from Nov 9-29th, as reported the Georgia Forestry Commission. • Satellite photo showing the area in which the Arabia Bay swamp fire was burning. Mainly composed of brush and leaf litter, the fire was believed to be caused by an arsonist. Fire caused dense smoke and reduced visibility in Homerville and Valdosta areas.

6. Additional Analysis • Fire lead to smoke pollution and reduced visibility in Valdosta area where PM2.5 standard was violated. • This event was analyzed the with MODIS and CALIPSO data. Surface PM2.5 MODIS Fires 6

7. High Pressure system centered over the mid-Atlantic moved eastward, keeping mostly dry stable conditions over central and south GA, along with mostly clear skies Good pre-frontal build-up of PM2.5 ahead of the approaching cold front (stagnant conditions) may have helped concentrations at VLD go even higher Satellite Surface Map – Nov 12, 2010

8. Objective WRF Mesoanalysis • Local model run internally • at EPD. • Domain chosen for fire • region over South Georgia. • Wind (barbs), mean • Sea-level pressure • (contours), and Relative • Humidity (color fill) • are plotted. • Winds veer from northerly • to northeasterly from • 11/13 into 11/14. • PM 2.5 concentrations • rapidly increase on 11/14, • as smoke is transported • from the fire region (near • Homerville) towards the • Valdosta monitoring site. EPD’s WRF-ARW is initialized with NAM12 data

9. RUC Forecast Time-Height Section For Homerville, GA Light low-level northeasterly flow transported smoke into Valdosta from the fire region

10. Visible Imagery/RUC Analysis

11. Aqua Modis RGB – Southeast (11/14)

12. CALIPSO – Backscatter Plot

13. CALIPSO 532nm total aerosol backscatter and surface [PM2.5]Early morning CALIPSO overpass captures smoke plume from Arabia Bay Fire Arabia Bay Fire Source: Data accessed and image generated by U.S. EPA Remote Sensing Information Gateway Data Sources: CALIOP 532nm TAB (NASA-LaRC) and surface [PM2.5] – EPA AQS

14. Close up Image of CALIOP 532nm total aerosol backscatter and surface [PM2.5]Early morning CALIPSO overpass captures smoke plume from Arabia Bay Fire Source: Data accessed and image generated by U.S. EPA Remote Sensing Information Gateway Data Sources: CALIOP 532nm TAB (NASA-LaRC) and surface [PM2.5] – EPA AQS

15. GOES Smoke Concentration Product Animation of Smoke Plume Detection • Semi-quantitative retrieval of column average smoke concentration (µg/m3) using AOD and fire hot spots from GOES • Uses source apportionment and pattern recognition techniques to isolate smoke aerosols from other type of aerosols • Smoke mass concentration (mc) is obtained using AOD (τ), mass extinction efficiency (k), and aerosol height (h) • Product used by NWS for operational smoke forecast verification Smoke AOD Image Original AOD Image FMS = 43% Rolph et al., Verification of NOAA Smoke Forecast: the 2007 Fire Season, Weather and Forecasting, 2009

16. Diurnal Variation of PM2.5 Emissions Observed by GOES • Fewer fires in Georgia • Fires did not always die down during the night • Smoke transport very localized • Agricultural burning • No night time fire activity • Significant amount of emissions • Smoke from these fires spread far and wide 16

17. Evolution of Smoke Aerosol on November 11, 2010 1515 1545 1615 1645 1715 1745 1815 1845 1915 2015 2145 2115 GOES Imagery MODIS Imagery 17

18. Additional Exceptional Event Example (2/11/08) Warehouse fire in South Fulton County (GA) caused hourly PM2.5 values to increase at EPD Monitoring stations

19. EE Case Study – May 22nd, 2007 • Southeasterly winds around a strong surface ridge centered off the New England coast • Skew-T plot for FFC at 12z on 22 May, showed a strong morning temperature inversion • Winds pushed smoke northwest from the Waycross fires and concentrated the smoke at ground level • Yorkville monitoring site had an O3 violation on 22 May corresponding with high PM2.5 values

20. AOD and Visible Imagery Visible Satellite Imagery (Terra MODIS) for 22 May, showing smoke plumes from Waycross streaming up towards NW Georgia MODIS Aerosol Optical Depth imagery showing high AOD corresponding with smoke plumes on visible satellite

21. Satellite Fire Detection & Back Trajectory

22. Summary Several meteorological tools (Trajectories, satellite imagery, synoptic conditions) could be utilized when characterizing exceptional events. In fire/smoke activity, other meteorological factors could have contributed to enhanced particle pollution levels, such as approaching frontal systems and pre-frontal pooling. Easier to predict due to long duration and availability of surface data. Some exceptional events are more frequent and clear-cut than others, such as the Arabia fire/smoke and Okefenokee Swamp fire cases.

23. Acknowledgements • Nyasha Dunkley, (Georgia Environmental Protection Division) • Amy K. Huff(Battelle Memorial Institute) • Shobha Kondragunta, (NOAA/NESDIS) • Sean Miller, (Georgia Environmental Protection Division) • Jim Szykman, (NASA LARC)