Aerosol optical properties measured from aircraft, satellites and the ground during ARCTAS - their relationship to CCN, aerosol chemistry and smoke type Yohei Shinozuka*, John Livingston, Jens Redemann, Phil Russell, Roy Johnson, S Ramachandran (NASA Ames), Tony Clarke, Cameron M c Naughton, Steffen Freitag, Steve Howell, Volodia Kapustin, Vera Brekhovskikh (University of Hawai’i), Terry Lathem, Thanos Nenes (Georgia Tech) Brent Holben, Norm O'Neill, Bruce McArthur and Alain Royer (AERONET)

In this talk… Consistency check among the P-3 aircraft, ground and satellite observations of spectral aerosol optical depth (AOD) Linking CCN and optical properties Optical characterization of aerosol composition and smoke type

CONSISTENCY CHECK AATS-14

An example of extinction profile See also HSRL talk. 350 (Surface) AOD below P-3: (150 m * 30.5 Mm -1 ) AOD above P-3 (measured with AATS-14): Layer AOD over aircraft altitudes (500 – 6250 m GPS) : at 550 nm PRELIMINARY DATA Clarke, M c Naughton, Freitag, Howell et al.

HiGEAR layer AOD was typically within 10% of the AATS’s for the 35 spiral vertical profiles with altitude gain/loss greater than 1 km under clear sky with AATS and HiGEAR instruments running. PRELIMINARY +10% :1 agreement -10%

Time = HiGEAR Dry Scattering 4000 Mm -1 at 550 nm, AATS AOD 2.5 at 519 nm in the smoke. The high spatial variability prevented agreement between AATS and HiGEAR. Marker size proportional to dry scattering Camsell & Viking fires north of Lake Athabasca

Fort McMurray AERONET PIs: Holben, O'Neill, McArthur and Royer AERONET P-3 and AERONET AODs P-3

PEARL at Eureka Saturn Island off Vancouver Fort McMurray AERONET PIs: Holben, O'Neill, McArthur and Royer P-3 and AERONET AODs agreed within <0.01 (excellent!) – 0.02 (good) during 3 fly-over events, at all wavelengths but 1.6 um.

OMAERO OMAERUV MODIS Comparison of AATS with Satellites (OMI and MODIS) MODIS, OMI P-3 AOD (380 nm)

Comparison of AATS, OMI, and MODIS AOD spectra Preliminary J. Redemann, J. Livingston, Torres, Veihelmann, Veefkind

ARCTAS: 30 June 2008 P-3B Flight Track

MODIS AOD MODIS % cloud OMAERUV (470 nm) OMAERO MODIS P-3B flight track color-coded by AATS AOD (451 nm) ARCTAS: 30 June 2008 Note: Google Map from July 1, 1545 UT AATS: UT Aqua: UT Aura: UT

ARCTAS: 30 June 2008 smoke sulfate smoke sulfate OMAERUV and AATS AOD spectra OMI retrievals in highlighted cells likely cloud-contaminated smoke weakly abs OMAERO and AATS AOD spectra smoke Cloud-clearing turned off for OMAERO retrievals Retrievals produced with cloud-clearing on

ARCTAS: 30 June 2008 OMAERO OMAERUV AATS MODIS MODIS AOD (470 nm) OMI MODIS

220 km The first half of the P-3 July 3 flight

The first half of the P-3 July 3 flight encountered a well-mixed local pollution layer up to ~2 km GPS altitude and a long-range transport air mass above, both homogenous over >200 km. 220 km HiGEAR TSI Neph. Dry Scat. Coeff. (Mm-1) at 550 nm

PRELINARY MODIS 3-km resolution product from Remer and Mattoo. MODIS

nm 1:1 -15% % MODIS 3-km resolution product from Remer and Mattoo. (HiGEAR extinction * radar altitude) MODIS MODIS underestimated the AOD in some pixels.

CCN AND OPTICAL PROPERTIES

CCN concentration at supersaturation 0.3 – 0.4% is related to the column AOD at 354 nm typically with a geometric standard deviation of 3 (vertical bar). (Shown are data taken at GPS Altitude < 1000 m during ARCTAS Summer over Canada only.) (Lathem and Nenes)

AOD does not tell near-surface extinction, particularly with high scattering. We need to use better assessment of extinction (e.g., HSRL). <1000 m GPS altitude

CCN concentration is related to in-situ dry extinction coefficient with a geometric standard deviation of ~2. (Lathem and Nenes)

AEROSOL COMPOSITION AND SMOKE TYPE

Dark smoke from flaming fires White smoke from smoldering fires White smoldering and black flaming identified based on Tony Clarke’s flight report.

Dark smoke from flaming fires White smoke from smoldering fires Aerosol evolution in downwind transport? Characterization of smoke types and age with the wavelength dependence of scattering and SSA Smoke after evolution, or pollution from other sources? To be investigated.

Summary AATS, HiGEAR and AERONET measurements of AOD agreed well, except for some profiles with high spatial variability associated with forest fire smoke. Comparison with satellite observations is in progress. CCN concentration is related to single wavelength light extinction typically with a geometric standard deviation of 2. Smoke type and age may be characterized by the wavelength dependence of scattering, that of absorption and SSA. Thanks Ellen Baum from the Clean Air Task Force for supporting my travel.

EXTRA SLIDES

The humidity response of aerosol scattering was often negligible in Canada’s forest fire smoke we sampled. Both gamma and ambient RH were almost always too low to matter (gamma< 0.53 and ambient RH <50% for two thirds of our samples).

CALIPSO profile, all adjacent pro- files yield no aerosol retrieval