Comparison of aerosol classification results from airborne high spectral resolution lidar (HSRL) measurements and the CALIPSO vertical feature mask

Abstract

The NASA Langley Research Center (LaRC) airborne High Spectral Resolution Lidar (HSRL) on the NASA B200 aircraft has acquired large datasets of aerosol extinction (532nm), backscatter (532 and 1064nm), and depolarization (532 and 1064nm) profiles during 18 field missions across North America since 2006. The lidar measurements include scale-invariant aerosol parameters that vary with aerosol type but not concentration. These have been used to qualitatively classify HSRL aerosol measurements into eight separate composition types. The classification methodology uses models formed from “training cases” with known aerosol type. The remaining measurements are then compared with these models using the Mahalanobis distance. Aerosol products from the CALIPSO satellite include aerosol type information as well, which must be inferred using aerosol loading-dependent observations and location information as input to the aerosol retrieval. The HSRL instrument regularly flies over the CALIPSO satellite ground track, presenting the opportunity for comparisons between the HSRL aerosol typing and the CALIPSO Vertical Feature Mask product, giving insight into the performance of the CALIPSO aerosol type algorithm.