Validation of aerosol optical depth and climatology of aerosol vertical distribution in the Taklimakan Desert

Based on ground–based sun–photometer remote sensing of aerosol optical depth (AOD) at Tazhong, a site located at the center of the Taklimakan Desert in 2007 and 2008, AOD retrieved from Cloud–Aerosol and Infrared Pathfinder Satellite Observations (CALIOP) data were validated. Six years vertical profiles of aerosol extinction coefficient in the Taklimakan Desert were then analyzed. A good agreement between ground–based and CALIOP remote sensing AOD data was derived, with the correlation coefficient being 0.95. CALIOP slightly underestimated AOD that is likely due to lower lidar ratio of dust than the real value in the CALIOP aerosol algorithm. Pronounced inter–annual and seasonal variations of vertical profiles were revealed by the CALIOP retrievals. The height of dust aerosol layer can reach 4–5 km, which is more pronounced in spring and summer. Larger and smaller extinction values were observed in spring (March, April and May) and in later autumn (October and November), respectively. Dominant contribution of dust was clearly shown by the vertical profiles of color ratio (CR) and particle depolarization ratio (PDR).