Under prior NSF support, the PI conducted the field phase of the Cumulus Photogrammetric, In-situ and Doppler Observations (CuPIDO) and performed preliminary analysis of the collected data. Observational assets employed during the project included digital cameras, automated surface mesonet stations, GPS based balloon sounding systems and the Wyoming King Air research aircraft with 95 GHz airborne Doppler radar.
The fundamental hypotheses around which CuPIDO is based are that the onset of orographic convection results from the convergence of boundary layer over the mountain and local surface heat fluxes, leading to local boundary-layer deepening to the level of free convection and that subsequent development of the convection and thunderstorm development is governed by mutual interaction of cumulus and the environment. In particular, it is believed that moistening of the profile and/or that removal of stable layers though the action of shallow convection provides a favorable environment for deep convection. The erosion of thermals by dry air may be more pronounced in the desert southwest, but the conditioning of the environment by convection as a means of organizing convection may be important in general.
In this research, the Principal Investigator will refine and automate segmentation and stereo analysis techniques and utilize these to analyze data collected during CuPIDO. A description of the surface forcing, onset of the mesoscale upslope flow, triggering of the convection and subsequent development of deep convection will be obtained. Detailed development of the structure of convective cells and the evolution of the surrounding environment will be provided through the combination of in-situ, Doppler and photogrammetric data along with simulations from a cloud resolving model.
Intellectual Merit: The goal is to extend understanding of fundamental aspects of cumulus development by examining the mechanics of cumulus entrainment/detrainment, timing of the transition from shallow to deep convection and interaction of cumulus with the environment under varying shear, stability and moisture profiles. By extracting quantitative information from the images automatically, the Principal Investigator will be able to process large numbers of cases and extend and generalize the results of previous work on this subject. In particular, he will focus on refining classical conceptual models resulting from laboratory analogs and those emerging from high resolution numerical simulations.
Broader Impact: In addition to extending understanding of the fundamentals of cumulus convection, this information will be of use to operational forecasters in the desert southwest. The evolution of the convective boundary layer over the elevated terrain is largely unexplored. A compilation of convective development under different environmental conditions will allow forecasters to relate conditions in the valley to those in the regions where the storms are triggered. The data collected during this project will be useful in designing and tuning cloud parameterizations for numerical weather prediction, meso- and cloud resolving process model studies and large-scale, general circulation and climate models. This project also relies on a synergy between disciplines, as computer science and image processing are essential parts of the analysis.
