Bob Rauber Home Page

Department of Atmospheric Sciences - University of Illinois

Bob Rauber                                                            University of Illinois

Research-PLOWS
The Profiling of Winter Storms (PLOWS) was organized to study the dynamic and microphysical processes that govern the spatial and temporal variability of precipitation in the warm frontal and “wrap-around” deformation region of extratropical cyclones.  The research involves a two year field campaign and modeling studies with the Weather Research and Forecasting (WRF) model. PLOWS is addressing the following outstanding scientific questions: 1) What are the predominant spatial patterns of organized precipitation substructures, such as bands and generating cells, in these quadrants and how do they evolve? 2) How do frontal scale systems above and within the boundary layer such as warm fronts, cold fronts aloft, and occluded fronts relate to these precipitation substructures? 3) What are the thermodynamic and kinematic structures of these frontal systems including the distribution of moisture and vertical motion? 4) What instabilities and types of mesoscale forcing (e.g., moist symmetric instabilty, moist frontogenesis, gravity waves, and elevated upright convection) control the generation and evolution of precipitation substructures? 5) How do microphysical processes vary between the different precipitation substructures and what are the consequences? 6) Is instability triggered in ice-saturated ascent critical in some of these instances and is it through the release of the latent heat of deposition that instabilities can persist?

PLOWS was developed as a two year campaign. The first year was ground-based only, and the second year involved the use of the National Center for Atmospheric Research NCAR C-130 aircraft. The first year campaign, occurring over the ~2 month period from February 6, 2009-March 31, 2009, involved the University of Alabama (UAH) Mobile Integrated Profiling System (MIPS), the UAH Mobile Alabama X-Band (MAX) Dual Polarization Doppler Radar, the NCAR Mobile Integrated Sounding System (MISS), and the University of Missouri (UM) rawinsonde system.  The second year campaign occurred between November 1, 2009 and March 10, 2010 with a one month break from December 15-January 14, and included the same platforms as the first plus the C-130.

At the University of Illinois, we are pursuing a number of research avenues involving data analysis and modeling. We are analyzing detailed, high resolution observations of precipitation substructures using four mobile ground-based observing systems, the University of Alabama at Huntsville Mobile Integrated Profiling System, the Mobile Alabama X-band dual polarization radar, and the NCAR Mobile Integrated Sounding System, and the University of Missouri sounding system, along with the NCAR C-130 Aircraft equipped with microphysical probes and the Wyoming Cloud Doppler Radar and Cloud Lidar. We will also simulate the precipitation substructures using the Weather Research and Forecasting Model at high horizontal and vertical resolution . You can learn more about the datasets and the project at the PLOWS website. As of early 2011, we are working hard on analysis and expect the first publications to come out in about a year.