Steven successfully defended his PhD proposal on April 26, 2011.

TITLE:
Measurement of Cloud Droplet Distribution Parameters: a polarized, multi-angle eye toward cloud microphysics

ABSTRACT:
From radiative forcing effects to a cloud's evolution toward the onset of precipitation, the droplet size distribution (DSD) in a cloud has tremendous influence on the cloud's development and its impact on Earth climate systems.

Most common remotely sensed droplet size information is centered on retrieving the effective radius of the droplet distribution and, therefore, is largely focused on the radiative effects of the cloud.

Effective radius is but a small part of the picture where cloud microphysics and the connection between cloud evolution and atmospheric aerosols are the focus. For more microphysically motivated studies, higher moments of the DSD are needed. Techniques exist for retrieving the effective variance through the use of the polarized signal in the light scattered from the droplet field. This extends our view into the DSD parameter space but is limited to somewhat narrow droplet distributions.

The UMBC Laboratory for Aerosols, Clouds and Optics (LACO) has developed, and employed in the field, several generations of polarimetric remote sensing cameras to measure droplet distribution information and is currently developing next generation multi-angle, polarimetric imaging instrumentation for aircraft and satellite remote sensing of clouds and aerosols.

This proposal discusses the use of LACO imaging polarimeters for droplet size spectrum measurement and the development of techniques to extend the droplet size retrieval to wider spectra using multi-angle information in future generation imaging polarimeters.