AERONET Processing Algorithms Refinement AERONET Workshop May , 2004, El Arenosillo, Spain

AERONET Data Flows Flux measurements Direct - =340, 380, 440, 500, 670, 870, 940, 1020 nm Diffuse - =440, 670, 870, 1020 nm (alm, pp, pol) Calibration and processing information Aerosol optical depth and precipitable water computations Holben et al. RSE, 1998 Holben et al. JGR, 2001 Holben et al. RSE, 1998 Holben et al. JGR, 2001 Smirnov et al. RSE, 2000 Smirnov et al. RSE, 2000 Dubovik and King JGR, 2000 Dubovik et al. JGR, 2000 Dubovik and King JGR, 2000 Dubovik et al. JGR, 2000 Cloud screening and quality control Eck et al. JGR, 1999 Eck et al. JGR, 1999 Inversion products Volume size distribution (0.05<R<15 mm), refractive index, single scattering albedo (l=440, 670, 870, 1020 nm)

AERONET Data Flows Current and future additions Flux measurements nm (412, 532, 555 nm) Sun - =340, 380, 440, 500, 670, 870, 940, 1020 nm nm (412, 532, 555 nm) +500, 1640 nm? 340, 380 nm Sky - =440, 670, 870, 1020 nm + 500, 1640 nm + ? 340, 380 nm H 2 O, CO 2, CH 4 Calibration and processing information H 2 O, CO 2, CH 4 (1020, 1640, 940 nm) + extra  a (1020 nm) Aerosol optical depth and precipitable water computations (1020, 1640, 940 nm) + extra  a (1020 nm) Cloud screening and quality control Inversion products Almucantar retrievals - spherical and spheroid models (4 wavelengths), level 2 6 wavelengths+ ? 340, 380 nm Almucantar retrievals - 6 wavelengths + ? 340, 380 nm Principal plane retrievals - 4 wavelengths, level 2; ? 6 wavelengths ? Combined retrievals (almucantar and principal plane)

Current Processing Algorithm l Extraterrestrial Solar Flux - Neckel and Labs 1981; and Frohlich and Wehrli 1981 l Rayleigh optical depth - Edlen 1966 l Ozone amount - LUT (5ºx 5º Lat Long) - London et al l Water vapor content - Bruegge et al. 1992; Reagan et al l Water vapor correction for AOD (1020 nm) - none l CO2, CH4, WV for AOD (1640 nm) - N/A

Processing Algorithm Refinement l Extraterrestrial Solar Flux - Woods et al l Rayleigh optical depth - Bodhaine et al l Ozone amount - LUT (1ºx 1º Lat Long) - TOMS data l Water vapor content - Michalsky et al. 1995; Schmid et al l Water vapor correction for AOD (1020 nm) - LBLRTM l CO2, CH4, WV for AOD (1640 nm) - LBLRTM

Extraterrestrial Solar Flux

Courtesy Dr. Jay Herman, code 916, NASA/GSFC

Rayleigh Optical Depth

T w = exp(-A(mu) B ) Ln V( ) + m[  a ( )+  r ( )]= = Ln [V 0 ( )d -2 ] - A(mu) B V( ) = V 0 ( )d -2 exp{-m[  a ( )+  r ( )]}T w ( ) T w ( ) = ∫ E 0 ( )S( )exp[-m  w ( )] d / E 0 ( )S( )d

Parameters A and B for various filter batches

Optical Depth Correction at 1020 nm

Optical Depth Correction at 1640 nm

AERONET Precipitable Water Comparison

AERONET-GPS Precipitable Water Comparison

What to do next l Recalibrate Master instruments (water vapor channel only) l Recalculate calibration constants (water vapor channel only) for all instruments in the network l Update database on water vapor content l Quality assure PW (WVC) database l Compare QC/QA PW with GPS and MWR retrievals