Application of the CALIOP Layer Product to Evaluate the Vertical Distribution of Aerosols Estimated by Global Models: AeroCom Phase I Results

The CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization) layer product is used for a multimodel evaluation of the vertical distribution of aerosols. Annual and seasonal aerosol extinction profiles are analyzed over 13 sub-continental regions representative of industrial, dust, and biomass burni...

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Published inNASA Center for AeroSpace Information (CASI). Journal Articles
Main Authors Koffi, Brigitte, Schulz, Michael, Dentener, Frank, Diehl, Thomas, Easter, Richard, Ghan, Steven, Gimoux, Paul, Gong, Sunling, Horowitz, Larry W, Iversen, Trond, Kirkevag, Alf, Koch, Dorothy, Breon, Francois-Marie, Krol, Maarten, Myhre, Gunnar, Stier, Philip, Takemura, Toshihiko, Griesfeller, Jan, Winker, David, Balkanski, Yves, Bauer, Susanne, Berntsen, Terje, Chin, Mian, Collins, William D
Format Journal Article
LanguageEnglish
Published Hampton NASA/Langley Research Center 19.05.2012
Subjects
Aerosols
Altitude
Annual variations
Biomass burning
Climatology
Computer simulation
Diagnostic systems
Dust
Lidar
Mathematical analysis
Northern Hemisphere
Vertical distribution
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Summary:The CALIOP (Cloud-Aerosol Lidar with Orthogonal Polarization) layer product is used for a multimodel evaluation of the vertical distribution of aerosols. Annual and seasonal aerosol extinction profiles are analyzed over 13 sub-continental regions representative of industrial, dust, and biomass burning pollution, from CALIOP 2007-2009 observations and from AeroCom (Aerosol Comparisons between Observations and Models) 2000 simulations. An extinction mean height diagnostic (Z-alpha) is defined to quantitatively assess the models' performance. It is calculated over the 0-6 km and 0-10 km altitude ranges by weighting the altitude of each 100 m altitude layer by its aerosol extinction coefficient. The mean extinction profiles derived from CALIOP layer products provide consistent regional and seasonal specificities and a low inter-annual variability. While the outputs from most models are significantly correlated with the observed Z-alpha climatologies, some do better than others, and 2 of the 12 models perform particularly well in all seasons. Over industrial and maritime regions, most models show higher Z-alpha than observed by CALIOP, whereas over the African and Chinese dust source regions, Z-alpha is underestimated during Northern Hemisphere Spring and Summer. The positive model bias in Z-alpha is mainly due to an overestimate of the extinction above 6 km. Potential CALIOP and model limitations, and methodological factors that might contribute to the differences are discussed.