Smoke plume optical properties and transport observed by a multi-wavelength lidar, sunphotometer and satellite Lina Cordero a,b Yonghua Wu a,b, Barry Gross a,b, Fred Moshary a,b,Sam Ahmed a,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 92 nd Annual Meeting New Orleans, January 22-26, 2012

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

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 properties 1. Consequently, smoke plumes affect climate radiation, air quality and visibility in the regional and continental scale. 3 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 92 nd Annual Meeting

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, AMERICAN METEOROLOGICAL SOCIETY 92 nd Annual Meeting 4

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. AMERICAN METEOROLOGICAL SOCIETY 92 nd Annual Meeting 5 Fig. 2 – Light Detection and Ranging System at the City College of New York

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. AMERICAN METEOROLOGICAL SOCIETY 92 nd Annual Meeting 6 Fig. 3 – AERONET Cimel sun/sky radiometer at the City College of New York

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. AMERICAN METEOROLOGICAL SOCIETY 92 nd Annual Meeting 7 Eq. 1 – Angstrom Exponent

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

Observation Results Smoke plume vertical distribution and optical properties AMERICAN METEOROLOGICAL SOCIETY 92 nd Annual Meeting 9 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

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. Observation Results AMERICAN METEOROLOGICAL SOCIETY 92 nd Annual Meeting 10 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

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, 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). AMERICAN METEOROLOGICAL SOCIETY 92 nd Annual Meeting 11 Fig. 7 - Satellite images showing smoke and fires area on August 13, 2007 (2pm), and NOAA-HYSPLIT trajectory

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

Observation Results Smoke Plume Sources and Spatial distribution AMERICAN METEOROLOGICAL SOCIETY 92 nd Annual Meeting 13 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) Fire-smoke source region Smoke stripes with mid-level AOD CALIPSO overpass nearby CCNY-lidar site showing dense smoke plumes

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

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 PM 2.5 loadings AMERICAN METEOROLOGICAL SOCIETY 92 nd Annual Meeting 15 Fig Time-height cross section of range-corrected lidar returns at 1064-nm and ground level PM 2.5 mass concentration at sites location in NYC nearby the lidar-site

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 PM 2.5 concentrations show the corresponding increasing trends. AMERICAN METEOROLOGICAL SOCIETY 92 nd Annual Meeting 16

Acknowledgments This work is partially supported by the research projects of NOAA #NA17AE1625 and NASA #NCC Authors greatly appreciate the data from: – NASA-AERONET, – NASA-MODIS observations, – NASA-CALIPSO and DAAC – NOAA-radiosonde, – HYSPLIT data, – Surface PM 2.5 data from NYDEC. AMERICAN METEOROLOGICAL SOCIETY 92 nd Annual Meeting 17