FYFD

Tag: cyclone

  • Uranus’s Polar Cyclone

    Uranus’s Polar Cyclone

    Uranus is an oddity among the planets of our solar system. Where other planets spin around an axis roughly in line with their orbital axis, Uranus spins on its side, placing its poles in line with the sun. On Earth, the polar regions are naturally colder the equator, but that doesn’t hold true for Uranus. Yet new observations of the ice giant show that it, like the other planets with atmospheres in our solar system, has a polar cyclone.

    Those observations are thanks to improvements in radio astronomy over the past couple decades. Uranus’s odd orbital geometry means that each of its poles are hidden from Earth for 42 years at a time; the current northern-hemisphere spring marks our first view of Uranus’s northern pole since 1965. In the recent observations, researchers saw a bright spot on the pole, surrounded by a faint darker ring. The team modeled the temperature and gas composition necessary to match their observations and found that those patterns were consistent with a cyclone sitting at the northern pole. (Image credit: NASA/JPL-Caltech/VLA; research credit: A. Akins et al.; via Physics Today)

  • Stabilizing Jupiter’s Polar Storms

    Stabilizing Jupiter’s Polar Storms

    Four years ago, Juno discovered an octagon of eight cyclones at Jupiter’s northern pole and a similar five cyclone structure at its southern pole. Since then, both polygons have remained intact. What keeps the storm systems so stable is still an open question, but a recent observational study using Juno measurements found that an anticyclonic ring sits between the central and outer cyclones. In line with a previous theoretical study, this ring structure helps shield and stabilize the storm system.

    The underlying convective mechanisms of the storm remain a mystery, though, as the current study is limited in resolution to a scale of about 200 kilometers. (Image credit: NASA/JPL-Caltech/SwRI/ASI/INAF/JIRAM; research credit: A. Ingersoll et al.; via Gizmodo)

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    Protecting From Storm Surge

    The most dangerous and destructive part of a tropical cyclone isn’t the wind or rain; it’s the storm surge of water moving inland. This landward shift of ocean takes place because of a cyclone’s strong winds, which drive the water via shear. The depth storm surges reach depends on the wind speed and direction, shape of the shoreline, and many other factors, making exact predictions difficult.

    Fortunately, engineers can — with enough foresight and investment — build structures and networks to help protect developed land from storm surge flooding. (Image and video credit: Practical Engineering)

  • Jovian Polar Vortices

    Jovian Polar Vortices

    Jupiter’s atmosphere is full of enduring mysteries, and its poles are no exception. Instruments aboard the Juno spacecraft have gotten a better look at Jupiter’s North and South poles than any previous mission, and what they’ve found raises even more questions. Both of Jupiter’s poles feature a central cyclone ringed by other, similarly-sized cyclones. The North pole has eight outer cyclones (top image), while the South pole has five (bottom image), shown above in infrared. Despite being close enough that their spiral arms intersect, the cyclones don’t seem to be merging into something like Saturn’s polar hexagon. For now, scientists don’t know how this arrangement formed or why it persists, but the longer Juno can study the vortices up close, the more we’ll learn. (Image credit: NASA/JPL-Caltech/SwRI/ASI/INAF/JIRAM; research credit: A. Adriani et al.; submitted by Kam-Yung Soh)

  • In the Eye of a Hurricane

    In the Eye of a Hurricane

    Although eyes are common at the center of large-scale cyclones, scientists are only now beginning to understand how they form. Since real-world cyclogenesis is complicated by many competing effects, researchers look at simplified model systems first. A typical one uses a shallow, rotating cylindrical domain in which heat rises from below. The rotation provides a Coriolis force, which shapes the flow. In particular, it causes a boundary layer along the lower surface of the domain, creating a thin region where the flow moves radially inward. (Its opposite forms at the upper surface of the domain, sending flow radiating outward.) Like an ice skater spinning, the flow’s vorticity intensifies as it approaches the central axis of rotation. When the conditions are right, this intensely swirling boundary layer flow lifts up into the main flow, forming an eyewall. The eye itself, it turns out, is merely a reaction to the eyewall’s formation. (Image credit: S. Cristoforetti/ESA; research credit: L. Oruba et al.)

  • Juno’s Citizen Science

    Juno’s Citizen Science

    The Juno mission’s JunoCam has been producing stunning photos each time the spacecraft swoops past Jupiter. The instrument has a planning team, but its primary use is for citizen scientists, who have been suggesting images to take each orbit and have been processing those images. Most of the photos we see are like the one on the left above – photos that have been heavily color-enhanced to highlight details. The image on the right shows what Jupiter would look like to the human eye. Look closely, and you’ll catch many of the same colors and shapes in both photos. 

    At a recent conference, a member of JunoCam’s team presented scientific results that have come from the instrument, including analysis of Jupiter’s polar storm systems (8 vortices for the north pole and 5 for the south), tantalizing hints at Jovian equivalents to earthly cloud types, and more. She also announced a new Analysis page where members of the public can both see the science in progress and participate first-hand! (Image credit: NASA / SwRI / MSSS / G. Eichstädt / S. Doran; NASA / JPL-Caltech / SwRI / MSSS / B. Jónsson; via E. Lakdawalla; submitted by jshoer)

  • Recreating Hurricanes

    Recreating Hurricanes

    Hurricane-related winds and storm surge cause massive damage every year. Understanding and being able to predict the impact of these storms on coastal structures can help save lives and properties. Until recently the most ferocious of hurricanes–category 5 storms that feature winds above 250 kph (150 mph)–could not be recreated in a laboratory scale. Now the University of Miami’s SUSTAIN (SUrge-STructure-Atmosphere INteraction) facility can produce category-5 equivalent winds, waves, and surge in a controlled environment. The massive test section measures 18 m x 6 m x 2 m and can be filled with over 140,000 liters of saltwater. The acrylic walls of the facility let researchers use optical flow diagnostics like particle image velocimetry (PIV) to measure flow anywhere in the test section. Some of their planned studies include experiments on how oil spills behave in storms and how strong aquaculture nets must be to maintain their catch through a storm. It will also be used to study interactions between buildings and storm surge. For more, check out their website or this video from the Weather Channel. (Image credits: Gort Photography, AFP/K. Sheridan, AP Photo/W. Lee; SUSTAIN Laboratory)

  • Coriolis

    Coriolis

    There’s an infamous supposition about drains swirling one way in the Northern Hemisphere and the other way in the Southern Hemisphere. Destin from Smarter Every Day and Derek from Veritasium have put the claim to the test with experiments on either side of the globe. First, go here and watch their synchronized videos side-by-side. (To synchronize, start the left video and pause it at the sync point. Then start the second video and unpause the first video when the second video hits the sync point.) I’ll wait here.

    …

    That was awesome, right?! The demonstration doesn’t work with toilets because they’re driven by the placement of jets around the circumference. And your bathtub doesn’t usually work either because any residual vorticity in the tub gets magnified by conservation of angular momentum as it drains. It’s like a spinning ice skater pulling their arms in; the rotation speeds up. So, to get around that problem, Destin and Derek let their pools sit for a day to damp out any motion before draining. At that point, the Coriolis effect is strong enough to cause the pools to rotate in opposite directions when drained. You may wonder why the effect is so slight for the pools when it’s pretty stark with hurricanes and cyclones. The answer is a matter of scale. The pools are perhaps 2 meters wide, which means that the difference in latitude across the the pool is very slight and therefore, the differential speed imparted by the Earth’s rotation is also very small. Because hurricanes and cyclones are much larger, they experience stronger influence from the Coriolis effect. (Image credits: Smarter Every Day/Veritasium; via It’s Okay To Be Smart)

  • Hurricane Irene

    Hurricane Irene

    This August 25th satellite image shows Hurricane Irene over the Bahamas and Florida. Hurricanes are fueled largely by the release of heat as warm water vapor in the rising air condenses. The hurricane requires a body of warm water to sustain the process, which is why hurricanes weaken drastically after they make landfall. Over open water, the heat released by condensation fuels higher winds, which lowers the pressure at the center of the system and helps increase the rate of evaporation near the ocean surface, providing additional warm vapor for future condensation. See more photos of Irene from space, along with video from the ISS. #