Lina Cordero a,b Yonghua Wu a,b , Barry Gross a,b , Fred Moshary a,b ,Sam Ahmed a,b

1. Smoke plumeoptical properties and transport observed by a multi-wavelength lidar, sunphotometer and satellite Lina Corderoa,b Yonghua Wua,b, Barry Grossa,b, Fred Mosharya,b,Sam Ahmeda,b a NOAA-Cooperative Remote Sensing Science and Technology Center b Optical Remote Sensing Lab, Department of Electrical Engineering, The City College of New York AMERICAN METEOROLOGICAL SOCIETY 92nd Annual Meeting New Orleans, January 22-26, 2012

2. Outline • Motivation • Introduction • Instrumentation • Methodology • Observation Results • Case: Aloft smoke plumes from Idaho/Montana forest fires on August 14~15, 2007. (Origin: US northwest, Range: 2~8 km altitude, Angstrom Exponent ~ 1.8) • Conclusions • Acknowledgments AMERICAN METEOROLOGICAL SOCIETY 92nd Annual Meeting

3. Motivation • Large amounts of smoke aerosol can be injected into the atmosphere as a result of forest-fire and biomass burning. • Observations indicate that aerosol plumes potentially modify cloud physical, chemical and optical properties1. • Consequently, smoke plumes affect climate radiation, air quality and visibility in the regional and continental scale. Fig. 1 - Plumes of smoke from wildfires in Mexico and Texas on April 27, 2011, captured by MODIS/Aqua satellite 1 Kaufman et al., 2005; Sassen et al., 2003, 2008 AMERICAN METEOROLOGICAL SOCIETY 92nd Annual Meeting

4. Introduction • Analyze the smoke plume optical characteristics and long-distance transport using a ground-based multi-wavelength lidar, a sunphotometer and satellite observations in the New York City area. • Long-distance transport and origins of smoke plumes are illustrated by MODIS/Aqua satellite, CALIOP imageries and NOAA/HYSPLIT air backward trajectory analysis. • Event: • Aloft smoke plumes from Idaho/Montana forest fires on August 14~15, 2007. AMERICAN METEOROLOGICAL SOCIETY 92nd Annual Meeting

5. Instrumentation • Ground-based multi-wavelength elastic-Raman scattering lidar • Observe 2D vertical distribution of aerosols at wavelengths: 1064-, 532- and 355-nm. • Aerosol extinction and backscatter coefficient profiles (AOD). • Derive Angstrom exponents (e.g. spectral dependence of aerosol extinction or backscatter) to discriminate smoke plumes from cloud and dust particles. Fig. 2 – Light Detection and Ranging System at the City College of New York AMERICAN METEOROLOGICAL SOCIETY 92nd Annual Meeting

6. Instrumentation • AERONET Cimel sun/sky radiometer (CE-318) • Obtain aerosol optical depth (AOD) at 340~1020 nm by measuring the direct solar radiance wavelengths. • Derive aerosol microphysics parameters (volume size distribution and refractive index) are inverted from sky radiance measurements. • Fine-mode and coarse-mode aerosol optical depths from the spectral curvature of AOD. • Constrain lidar-derived multi-wavelength extinction profiles of aerosol plumes with the column AOD. Fig. 3 – AERONET Cimel sun/sky radiometer at the City College of New York AMERICAN METEOROLOGICAL SOCIETY 92nd Annual Meeting

7. Methodology • Angstrom exponent profile can be estimated as: • Small particles such as smoke aerosols have larger Angstrom exponent. • Large particles such as dust, sea salt and thin cloud have small Angstrom exponent. • Thus, it can be used to discriminate aerosol type. Eq. 1 – Angstrom Exponent AMERICAN METEOROLOGICAL SOCIETY 92nd Annual Meeting

8. Observation Results • Smoke plume vertical distribution and optical properties Two aerosol plumes Arriving aerosol plume Lower plume mixes with PBL Fig. 4 – Time-height cross section of range-corrected lidar returns at 1064-nm AMERICAN METEOROLOGICAL SOCIETY 92nd Annual Meeting

9. Observation Results • Smoke plume vertical distribution and optical properties Large Angstrom exponents indicate fine particles domination Aerosol multi-layer with homogeneous particle size Fig. 5 – Aerosol extinction and Angstrom exponent profiles a) Aug 14, 16:30-16:45 and b) Aug 15, 13:35-13:50 AMERICAN METEOROLOGICAL SOCIETY 92nd Annual Meeting

10. Observation Results • Smoke plume column optical properties • Aerosol plume intrusion - AOD and Angstrom Exponent increase. • Aerosol size distribution - Fine-mode volume dominance. • AOD and Angstrom Exponent remain high on next day. Fig. 6 – Aerosol optical depth, Angstrom exponent and particle size distribution (16:42 pm, Aug.14) observed by AERONET sunphotometer on Aug.14 and Aug.15, 2007 AMERICAN METEOROLOGICAL SOCIETY 92nd Annual Meeting

11. Observation Results • Smoke Plume Sources and Transport pathway • Large fires across the Northern Rockies in Idaho and Montana were captured by MODIS/Aqua satellite at 2:00 pm on Aug.13, 2007. By August 15, the smoke plumes began to canvas the US northeast. • NOAA-HYSPLIT shows the air mass traveled from Idaho/Montana forest fire area to the lidar site (~40-hour trip). Fig. 7 - Satellite images showing smoke and fires area on August 13, 2007 (2pm), and NOAA-HYSPLIT trajectory AMERICAN METEOROLOGICAL SOCIETY 92nd Annual Meeting

12. Observation Results Smoke-Plume Transport – GOES AOD AMERICAN METEOROLOGICAL SOCIETY 92nd Annual Meeting

13. Observation Results • Smoke Plume Sources and Spatial distribution CALIPSO overpass nearby CCNY-lidar site showing dense smoke plumes Fire-smoke source region Smoke stripes with mid-level AOD Fig. 8 - MODIS/Aqua image on 15 August, 2007 (Lines-D1, D2 and N1 are the CALISPO ground-tracks), CALIPSO-attenuated backscatter coefficients (track as shown by line-N1) AMERICAN METEOROLOGICAL SOCIETY 92nd Annual Meeting

14. Observation Results • Smoke Plume Sources and Spatial distribution • CALIPSO VFM products properly classify the layer as aerosol • CALIPSO VFM products further classify them as smoke Fig. 9 – CALIPSO classification of aerosol/cloud AMERICAN METEOROLOGICAL SOCIETY 92nd Annual Meeting

15. Observation Results • Lidar-derived AOD apportionment and smoke influence on local air quality • Aloft smoke plumes intrusion into the PBL, probably resulting in a significant increase in surface PM2.5 loadings Fig. 10 - Time-height cross section of range-corrected lidar returns at 1064-nm and ground level PM2.5 mass concentration at sites location in NYC nearby the lidar-site AMERICAN METEOROLOGICAL SOCIETY 92nd Annual Meeting

16. Conclusions • Smoke plumes optical properties and long-distance transport to the US east coast from US northwest are observed with the synergy measurements of ground-based multiple-wavelength elastic-Raman lidar, sun-photometer and satellite. • High Angstrom exponents indicate the fine-mode dominated in the plumes layers (~1.8). • The range-resolved lidar observations indicate that the elevated smoke plumes were entrained into the turbulent PBL, and the surface PM2.5 concentrations show the corresponding increasing trends. AMERICAN METEOROLOGICAL SOCIETY 92nd Annual Meeting

17. Acknowledgments • This work is partially supported by the research projects of NOAA #NA17AE1625 and NASA #NCC-1-03009. • Authors greatly appreciate the data from: • NASA-AERONET, • NASA-MODIS observations, • NASA-CALIPSO and DAAC • NOAA-radiosonde, • HYSPLIT data, • Surface PM2.5 data from NYDEC. AMERICAN METEOROLOGICAL SOCIETY 92nd Annual Meeting