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Atmospheric Scientific Visualization


Simulated severe thunderstorm, first view.  Data from Crystal Shaw and Bob Wilhelmson.  The orange contour lines are for vertical wind velocity, contoured at 3 m/sec. Vertical wind velocity is also mapped as the color onto the rain water isosurface contoured at 6 grams per grams of air. It also looks like the rainbow color map goes from purple (downdraft) to red (updraft).

Tornado MPG

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320x240 MPEG, 3.1MB  

 The NCSA Atmospheric/Oceanic Sciences Group, led by Dr. Robert Wilhelmson, is collaborating with Professor Mohan Ramamurthy of the University of Illinois Atmospheric Sciences Department in studies of the development and impact of Hurricane Opal. Opal, which reached Category 4 status with winds exceeding 150 mph prior to landfall, struck near Pensacola, Florida on Oct. 4, 1995. Along its path, Opal produced over 10 inches of rain in parts of Florida, Alabama and Georgia, and spawned 22 tornadoes. The storm caused extensive damage (over $3 billion dollars) and resulted in 59 deaths (9 in the U. S.). Given the population growth and development along its coasts, the U. S. is more vulnerable than ever to damage from hurricanes.  Adding to this vulnerability is a lack of skill for forecasts of the timing, intensity of wind, and rain near landfall.  Hurricane track prediction is perhaps one of the simplest and yet may become one of most important applications ensemble forecasting. Similarly, the prediction of hurricane intensity change (e.g. central pressure and peak tangential winds), one of the most difficult problems confronting the hurricane prediction community, can benefit from ensemble forecasting due to the many uncertainties in the description of processes influencing tropical cyclone intensity change in NWP models. Professor Ramamurthy has carried out a number of low-resolution simulations with the NCAR-Pennsylvania State University MM5 model as part of a study of forecast sensitivity, including the role of model initialization and physics, on hurricane track and intensity. The NCSA Atmospheric/Oceanic Sciences Group has previously carried out one higher (5 km horizontal) resolution simulation and is preparing to make an even higher resolution run in order to better model the observed landfall location of the hurricane and the associated heavy precipitation accompanying it. Ultimately the model-predicted rainfall is to be used with a runoff model to simulate the actual flooding that took place on this day, and still higher resolution simulations (incorporating additional nested grids) are anticipated. In addition, further visualization in the CAVE is planned to better study the structure and evolution of the eye at high resolution and the changes that occurred as the storm approached land, weakening from a category 4 storm when it was farther offshore. The combination of software (MM5/runoff connections) and hardware (CRAY Origin2000) technology and CAVE visualization will allow us to better simulate and understand the storm and its impact on the U.S. mainland.
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