Aerosol classification from airborne HSRL and comparisons with the CALIPSO vertical feature mask

[摘要] Aerosol classification products from the NASA Langley ResearchCenter (LaRC) airborne High Spectral Resolution Lidar (HSRL-1) onthe NASA B200 aircraft are compared with coincident V3.01 aerosolclassification products from the Cloud-Aerosol Lidar with OrthogonalPolarization (CALIOP) instrument on the CALIPSOsatellite. For CALIOP, aerosol classification is a key input to theaerosol retrieval, and must be inferred using aerosolloading-dependent observations and location information. Incontrast, HSRL-1 makes direct measurements of aerosol intensiveproperties, including the lidar ratio, that provide information onaerosol type. In this study, comparisons are made for 109underflights of the CALIOP orbit track. We find that 62% of theCALIOP marine layers and 54% of the polluted continental layersagree with HSRL-1 classification results. In addition, 80% ofthe CALIOP desert dust layers are classified as either dust or dustymix byHSRL-1. However, agreement is less for CALIOP smoke(13%) and polluted dust (35%) layers. Specific casestudies are examined, giving insight into the performance of theCALIOP aerosol type algorithm. In particular, we find that theCALIOP polluted dust type is overused due to an attenuation-relateddepolarization bias. Furthermore, the polluted dust type frequentlyincludes mixtures of dust plus marine aerosol. Finally, we find thatCALIOP's identification of internal boundaries between differentaerosol types in contact with each other frequently do not reflectthe actual transitions between aerosol types accurately. Based onthese findings, we give recommendations which may help to improvethe CALIOP aerosol type algorithms.

[学科分类] 几何与拓扑