Jacek Chowdhary 1,2 , Brian Cairns 1,2 , Michael Mishchenko 2

1. On the use of multi-angle, multi-spectral, photo-polarimetric remote sensing data to constrain aerosol properties Jacek Chowdhary1,2, Brian Cairns1,2, Michael Mishchenko2 1 Columbia University, 2 NASA/Goddard Institute of Space Studies

2. In 9 spectral bands from l = 412 to 2250 nm (412, 443, 555, 672, 865, 910, 1378, 1610, & 2250 nm) glint { R} 1. sun glint: profile Radiative closure experiment involving data from 6 research aircrafts, 2250 Im(m) est. several land sites, an ocean platform, and MISR & MODIS Re(m), SD, { P} { P} 2. to fine aerosol, ocean: or 670 410 ocean est. 3. fine & coarse aerosol: { R, P} { R, P} to Re(m), SD 2250 865 4. { R } { R} to fine aerosol, ocean: Im(m), ocean 670 410 Data sets and analyses • MISR Obtains I, Q, & U simultaneously, DDoLP< 0.2% ~ POLDER capability to obtain I, Q, U • POLDER • APS • AVHRR ~ MISR capability to obtain many views Views 240 angles covering +60°/–70° from nadir ~ MODIS capability to monitor many l • MODIS Quantity CLAMS data properties J. Atm. Sci. (2005), 1093-1117

3. In 9 spectral bands from l = 412 to 2250 nm (412, 443, 555, 672, 865, 910, 1378, 1610, & 2250 nm) I where Re(m) = 1.50 (410 nm) I = intensity re = .15 mm, DoLP = degree of linear polarization Im(m) = 0.02 ve = .2, e=eI eI where = uncertainty in I = 3.5% eDoLP glint = uncertainty in DoLP = (0.002)/(DoLP) { R} 1. sun glint: profile 2250 Im(m) est. Re(m), SD, { P} { P} 2. to fine aerosol, ocean: or 670 410 ocean est. sun 3. fine & coarse aerosol: { R, P} { R, P} to Re(m), SD back sun back sun 2250 865 total reflectance total reflectance total reflectance back 4. { R } { R} to fine aerosol, ocean: Im(m), ocean 670 410 viewing zenith angle viewing zenith angle viewing zenith angle Data sets and analyses • MISR Obtains I, Q, & U simultaneously, DDoLP< 0.2% • POLDER • APS • AVHRR Views 240 angles covering +60°/–70° from nadir • MODIS Data set: P =I × DoLP Quantity CLAMS data properties e=eI+eDoLP Error bars: DDoLP~ 1% no P in VIS MISR angles polarized reflectance polarized reflectance polarized reflectance J. Atm. Sci. (2005), 1093-1117 viewing zenith angle viewing zenith angle viewing zenith angle

4. To accurately constrain aerosol properties requires polarization data for  a large number of viewing angles & wavelengths with DDoLP≤ 0.2%   Limiting any of these requirements in e.g. the VIS significantly reduces Such limitations also significantly affect the ability to retrieve ocean the capability to identify the composition of fine mode aerosol particles color variations from total reflectance data Conclusions

5. sun back D-P mix D-P mix 0.03 mg/m3 0.10 mg/m3 relatively small sun: 0.30 mg/m3 1.00 mg/m3 j-j0 = 0º j-j0 = 180º 3.00 mg/m3 back: inherently small a (Chl,l) b (Chl,l) q (Chl,l) Semi-analytical Total Polarized Data [Chl] l RT results underwater light irradiance ratio RT results In situ polarimetry Ratio F11(cos q) F21(cos q) P (cos q) wavelength (nm) Underwater light scattering Special case retrieval ocean RT model RSP data (CLAMS) RT computations polarized reflectance Mie scattering function RT degree linear polarization (%) F (cos q) w hydrosol SD hydrosol m R (view, Chl, l) R (view) 410 nm viewing zenith angle scattering angle Q (deg) scattering angle Q (deg) Re(m) = 1.46 re = 0.15 mm Im(m) = .015 ve = 0.2 Chowdhary et al. (2006) Chowdhary et al. (2005)