PhD Proposal: Brent McBride
TITLE: Investigating Cloud Microphysical Properties with Hyper-Angular Imaging Polarimeter Measurements
ABSTRACT: The Hyper-Angular Rainbow Polarimeter (HARP) suite of instruments are wide FOV, hyper-angular imaging polarimeters for the microphysical sampling of clouds and aerosols from aircraft and space. The first of its kind, the hyper-angular, imaging capability of 60 view angles at 0.67um and narrow pixel ground footprint (400m at nadir) provides the technological advancement capable of highly accurate, full cloudbow retrievals. Built from successful technology, the HARP instruments are based on the Passive Aerosol and Cloud Suite (PACS, LACO-UMBC), a hyper-angular imaging polarimeter that flew during the NASA PODEX campaign in 2013.
Microphysical retrievals of clouds, and potentially aerosols, from HARP datasets will provide a greater estimation of long-standing climate uncertainties: aerosol direct/indirect effects, global fluctuations in aerosol composition, cloud-aerosol interactions, precipitation, and the variability of cloud droplet size distributions within the same cloud. These polarimetric observations also independently enhance radiometric microphysical retrievals, which are historically underdetermined and require particle shape and size assumptions to converge on a solution. This research will include geo-location and retrieval inter-validation exercises between HARP instruments, MODIS and VIIRS radiometers, and other airborne polarimeters, sensitivity studies related to the angular viewing density required for accurate cloudbow retrieval, and instrumental calibration error modeling. These studies will incorporate datasets from two HARP deployments; HARP CubeSat anticipates a launch in August 2017 into an inclined, ISS orbit, placing it in a unique position to interface with A-Train satellites, and AirHARP will participate in two aircraft campaigns in 2017: as part of the Lake Michigan Ozone Study (LMOS) on the NASA UC-12 aircraft in May and June and the Aerosol Characterization from Polarimeter and Lidar (ACEPOL) mission, onboard the NASA ER-2 over Southern California in October.