Investigating Elevated Aqua Modis Aerosol Optical Depth Retrievals Over The Mid-Latitude Southern Oceans

• Main Author: Toth, Travis
• Format: Text
• Language: unknown
• Published: UND Scholarly Commons 2012
• Subjects: Aerosols; Clouds; Satellite remote sensing; Aerosol Robotic Network
• Online Access: https://commons.und.edu/theses/1383; https://commons.und.edu/context/theses/article/2384/viewcontent/Toth_und_0156M_10208.pdf

A band of elevated aerosol optical depth (AOD) over the mid-latitude Southern Oceans has been identified in some passive satellite-based aerosol datasets such as Moderate Resolution Imaging SpectroRadiometer (MODIS) and Multi-angle Imaging SpectroRadiometer (MISR) products. In this study, Aqua MODIS (AM) aerosol products in this zonal region are investigated in detail to assess retrieval accuracy. This is done through multiple data sets, including spatially and temporally collocated cloud and aerosol products produced by the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) project for investigating AM AOD in this region with respect to lidar profiling of cloud presence. Maritime Aerosol Network (MAN) and Aerosol Robotic Network (AERONET) AOD data are also collocated with AM for surface context. The results of this study suggest that the apparent high AOD belt, seen in some satellite aerosol products based on passive remote sensing methods, is not seen in the CALIOP aerosol product based on an active remote sensing technique with an enhanced cloud detection capability and is not detected from ground-based observations such as MAN and AERONET data. The apparent high AOD belt, although largely attributed to stratocumulus and low broken cumulus cloud contamination as suggested by CALIOP products, could not be fully credited to cloud contamination. Collocated CALIOP data also suggest that the current cloud screening methods implemented in the over ocean AM aerosol products are ineffective in identifying cirrus clouds. Cloud residuals still exist in the AM AOD products even with the use of the most stringent cloud screening settings.