Berkeley Lab study shows that finer-detailed data captures effects of tropical cyclones
Surfers aren't the only people trying to catch big waves. Scientists at the Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) are trying to do so, too, at least in wave climate forecasts.
Hurricanes are seen generating big waves within the high-resolution, 25-km model (right side). The large waves show up as bright, yellow and red spots. These storms and resulting waves are almost entirely absent in the low-resolution, 100-km model (left).
Credit: Ben Timmermans and Michael Wehner/Berkeley Lab
Using decades of global climate data generated at a spatial resolution of about 25 kilometers squared, researchers were able to capture the formation of tropical cyclones, also referred to as hurricanes and typhoons, and the extreme waves that they generate. Those same models, when run at resolutions of about 100 kilometers, missed the tropical cyclones and the big waves up to 30 meters high.
Their findings, published in the Feb. 16 issue of Geophysical Research Letters, demonstrate the importance of running climate models at higher resolution. Better predictions of how often extreme waves will hit are important for coastal cities, the military, and industries that rely upon shipping and offshore oil platforms. And, of course, for surfers.
"It's well known that to study tropical cyclones using simulations, the models need to be run at high resolution," said study lead author and postdoctoral fellow Ben Timmermans. "The majority of existing models used to study the global climate are run at resolutions that are insufficient to predict tropical cyclones. The simulations in our study are the first long-duration global data sets to use a resolution of 25 kilometers. It's also the first time a study has specifically examined the impact of resolution increase for ocean waves at a global climatological scale."
The other authors on this study are Dáith? Stone, Michael Wehner, and Harinarayan Krishnan. All authors are scientists in Berkeley Lab's Computational Research Division (CRD).
Zooming in to detect hurricanes
Climate models work by simulating the exchange of air, water, and energy between the grid "boxes." In today's state-of-the-art climate models, these boxes are typically 100 to 200 kilometers wide. That level of detail is good enough to catch the formation and movement of midlatitude storms, the researchers said, because such systems tend to be quite large.
In contrast, tropical cyclones tend to cover a smaller area. While the overall footprint of a hurricane can be broad, the eye of a hurricane can be very compact and well defined, the researchers noted.
"The problem with that 100-kilometer resolution is that it misses key details of the hurricanes and tropical cyclones, which are clearly relevant to the generation of extreme waves," said Stone. "But going to a 25-kilometer resolution data set is computationally challenging. It requires 64 times more computational resources than a 100-kilometer simulation."
The study relied upon the data-crunching power of the National Energy Research Scientific Computing Center (NERSC), a scientific computing user facility funded by the DOE Office of Science and based at Berkeley Lab.
The researchers ran the Community Atmosphere Model version 5 (CAM5) climate model with data collected in three-hour increments at a low resolution of 100 kilometers and at a high resolution of 25?kilometers. They found that the high-resolution simulations included tropical cyclones where the low-resolution ones did not.
Crunching data to catch big waves
To see if the cyclones had an effect on waves, they then ran global wave models at both resolutions. They saw extreme waves in the high-resolution model that did not appear in the low-resolution ones.
"Hurricanes are tricky things to model," said Stone. "We've shown the importance of using a high-resolution data set for producing hurricanes. But the characteristics of hurricanes could change with the climate. People are making projections of changes in ocean waves in a future, warmer world. It's not clear if the 25-kilometer resolution is sufficient for capturing all of the processes involved in the development of a hurricane. But we do know that it's better than 100 kilometers."
While additional high-resolution simulations of the future are on the way, the researchers were able to take a first look at possible conditions at the end of the 21st century. Wehner noted that the biggest waves in Hawaii are projected to be substantially larger in a much warmer future world.
The researchers added that this study only looked at averages of wind-generated waves. One-off "rogue" or "freak" waves cannot be reproduced in these kinds of models, and large waves such as tsunamis are very different since they are caused by seismological activity, not the wind.
The data from this study will be made freely available for use by the wider scientific community.
"In the same way that weather patterns are part of the climate, ocean wave patterns are also part of the 'wave' climate," said Timmermans. "Ocean waves are relevant to the interaction between the ocean and the atmosphere, which affects the planet's climate as a whole."
This work was supported by DOE's Office of Science.
Lawrence Berkeley National Laboratory addresses the world's most urgent scientific challenges by advancing sustainable energy, protecting human health, creating new materials, and revealing the origin and fate of the universe. Founded in 1931, Berkeley Lab's scientific expertise has been recognized with 13 Nobel Prizes. The University of California manages Berkeley Lab for the U.S. Department of Energy's Office of Science. For more, visit http://www.
DOE's Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.
Sarah Yang | EurekAlert!
Microscopic trampoline may help create networks of quantum computers
17.07.2018 | University of Colorado at Boulder
Electronic stickers to streamline large-scale 'internet of things'
17.07.2018 | Purdue University
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
17.07.2018 | Life Sciences
17.07.2018 | Information Technology
17.07.2018 | Power and Electrical Engineering