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Stuart A. Young and Mark A. Vaughan

particulate extinction or backscatter profile. The transmittance corrections are calculated using the retrieved backscatter and extinction from the preceding steps and, consequently, are sensitive to the boundary conditions set at the first point, and to the assumed values of the lidar ratio and the multiple-scattering function. For solutions that are initialized in the near field (forward solutions), the two-way transmittance decreases as the solution proceeds away from the near point. As both analytical

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Mark A. Vaughan, Kathleen A. Powell, David M. Winker, Chris A. Hostetler, Ralph E. Kuehn, William H. Hunt, Brian J. Getzewich, Stuart A. Young, Zhaoyan Liu, and Matthew J. McGill

time, CALIOP can encounter a large number of dissimilar scenarios. In the span of ∼20 min, CALIOP observes instances of multiple cloud layers (e.g., at ∼43°N and ∼6°N); faint, possibly subvisible, cirrus (∼20°S, at ∼15 km MSL); lofted aerosol layers (∼32°N, ∼4 km vertically); aerosol layers beneath overlying cirrus (at the equator and at ∼16°S); cumulus embedded in boundary layer aerosols (∼26°N); and aerosol extending above broken cloud decks (∼10°S). The fundamental data products derived from the

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David M. Winker, Mark A. Vaughan, Ali Omar, Yongxiang Hu, Kathleen A. Powell, Zhaoyan Liu, William H. Hunt, and Stuart A. Young

cloud above the aerosol layer ( Fig. 5c ) is retrieved in the same way as in cloud-free conditions. When there are multiple layers—cirrus above boundary layer aerosol is a common situation ( Fig. 5d )—the highest layer is retrieved first, allowing the signal below to be corrected for the overlying attenuation. If there are more than two layers in the column, then the retrieved attenuation of all overlying layers is used for attenuation correction of the signal below. If the optical depth of the

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Ali H. Omar, David M. Winker, Mark A. Vaughan, Yongxiang Hu, Charles R. Trepte, Richard A. Ferrare, Kam-Pui Lee, Chris A. Hostetler, Chieko Kittaka, Raymond R. Rogers, Ralph E. Kuehn, and Zhaoyan Liu

size distributions during SEAS yields S a values of 20 sr at 532 nm and 45 sr at 1064 nm. This 532-nm S a value for marine aerosols is consistent with marine aerosol S a estimates by others ( Ansmann et al. 2001 ; Flamant et al. 1998 ; Reagan et al. 2001 ). Measurements during INDOEX in the marine boundary layer of the tropical Indian Ocean report a value of 23.5 sr at 532 nm ( Müller et al. 2007 ). In their climatological study of oceanic AERONET sites, Cattrall et al. (2005) report an

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William H. Hunt, David M. Winker, Mark A. Vaughan, Kathleen A. Powell, Patricia L. Lucker, and Carl Weimer

aperture product that is dictated by weight and electrical power limitations. Although the SNR can be improved by more vertical and horizontal averaging, the amount of averaging that is acceptable is limited by the spatial scale of the target. Early in the CALIOP design phase, day and night SNR requirements were established that took into account the required accuracy and the allowable amount of averaging for a number of targets and lighting conditions. Simulations done at various stages of the

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Zhaoyan Liu, Mark Vaughan, David Winker, Chieko Kittaka, Brian Getzewich, Ralph Kuehn, Ali Omar, Kathleen Powell, Charles Trepte, and Chris Hostetler

be classified as an ice cloud in the downstream data processing by the ice–water discrimination algorithm ( HuSI ) using the depolarization ratio measurement. Dust storms occur normally in dry and hot air conditions over the source regions during daytime due to the enhanced convection in a deepened boundary layer (e.g., Ackerman and Cox 1987 ; N’Tchayi Mbourou et al. 1997 ). By checking the midlayer temperature, the misclassified dense dust layers can be identified in most cases. In our

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