(Credit: Staff at RENCI at UNC Asheville and RENCI at East Carolina University and Kevin Hill, NC State department of marine, Earth and atmospheric sciences, also helped to develop these animations)
Hurricane season is upon us, and while no one can predict how many storms will blow our way this year, RENCI has worked to improve storm modeling and put new tools into the hands of emergency responders since Floyd (1999) and Isabel (2003) swept ashore on the North Carolina coast.
RENCI programs designed to help North Carolina deal with hurricanes and severe storms include:
Storm surge modeling for floodplain remapping
At the request of the North Carolina Floodplain Remapping Program, a RENCI-led team headed by Senior Scientist Brian Blanton uses the ADCIRC computer model, developed by UNC Chapel Hill Institute of Marine Sciences Director Rick Luettich, to delineate storm surge and flooding along North Carolina’s coast in more detail than ever before possible. This work will help to create new floodplain maps, which are required by the National Flood Insurance Program, and will guide developments from Currituck to Brunswick County. The maps also will help communities develop disaster response and evacuation plans. A RENCI supercomputer capable of trillions of calculations per second makes it possible to use the detailed storm surge model to generate the new floodplain maps. Because of this capability the North Carolina Division of Emergency Management received $5 million from FEMA to work with RENCI on studies that model the potential effects of sea level rise in coastal North Carolina.
In fact, the surge modeling for the new floodplain maps has been so successful that FEMA turned to RENCI to compute storm surge for floodplain maps in FEMA Region 3, which runs from the North Carolina-Virginia boarder north through Delaware.
High resolution modeling for emergency management and better forecasting
Every six hours during hurricane season, RENCI supercomputers come to life running the ADCIRC storm surge computer model. Using RENCI’s technical and computational resources, ADCIRC can run at very high resolution, showing details about water height down to the tens of meters (similar modeling in the past typically resolved details down to no more than a few kilometers). The high resolution results are especially useful for assessing local flooding and potential evacuation problems. RENCI scientists have developed visual computer programs that allow the model results to be displayed with Google Earth and Geographic Information Systems, making them easy to understand and easily used by emergency managers and forecasters. These storm surge products provide guidance to emergency managers and can be used by the National Weather Service to help with their forecasts.
“The storm surge models run at RENCI serve double duty,” said Luettich, also director of UNC’s Institute for Marine Sciences and RENCI chief scientist for coastal modeling. “They are used in the off season to help create FEMA floodplain maps, which make the state eligible for federal flood insurance and set insurance rates for years to come, and during hurricane season they are run as hurricanes threaten the coast to help emergency managers deal with flooding emergencies. That wouldn’t be possible without the technical and computational resources that RENCI provides.”
High resolution weather modeling
RENCI atmospheric scientist Brian Etherton and NC State Professor Gary Lackmann use the Weather Research and Forecasting (WRF) model to forecast wind speed, air pressure and other atmospheric conditions in much more detail than typical production forecasts.
Lackmann, a faculty member in NC State’s department of marine, Earth and atmospheric sciences, began working with RENCI two years ago because he needed more computing power for his research, one aspect of which explores how climate change could affect the intensity of tropical storms. Lackmann and Etherton are also exploring how to improve the accuracy of hurricane forecasts with a real-time WRF hurricane prediction system.
The WRF model, like the storm surge model, is produced several times a day using RENCI supercomputers. RENCI plans to provide these high resolution products to the National Weather Service, where researchers will be able to use them to improve their weather forecasts.
“We couldn’t create simulations with this level of detail without the computing power that RENCI provides,” said Lackmann. “The high-resolution forecasts that we produce let us represent physical processes driving the storms in greater detail than would otherwise be possible. They’re a great learning tool for researchers and forecasters because you can basically observe the model storm in great detail without putting yourself into the middle of an actual hurricane.”
“What’s unique about RENCI is its ability to turn research into products that are immediately and locally relevant,” added Luettich. “When I first turned to RENCI, my ADCIRC storm surge model was mainly being applied in the Gulf Coast. RENCI has played a critical role in adapting ADCIRC for North Carolina and has created an end-to-end system that looks at weather, surge, rain and hydrology as a whole system. RENCI turned a small plant into a garden and now people from other states are looking to RENCI for help creating their own gardens.”