Investigating the effects of air-mass history on cloud-aerosol interactions in different cloud regimes using AHSRL and trajectory cluster analysis

When using trajectory cluster analysis to classify modes of entry of air-masses over the in-situ Arctic High Spectral Resolution Lidar, a difference is observed in how these clusters of back-trajectories are statistically related to lidar observables such as aerosol backscatter or circular depolarization depending on the height at which the back-trajectories are initiated at. Possible mechanisms for this discrepancy are considered, namely this could be evidence for the effects of aerosol origin on ice and mixed-phased cloud nucleation and how this effects different cloud types. Specific observations of cloud nucleation by AHSRL will also be illustrated.