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Tag: atmospheric science

  • Explaining the Swirl of Wildfire Smoke

    Explaining the Swirl of Wildfire Smoke

    In recent years, smoke from powerful wildfires has raised questions among atmospheric scientists by always swirling in the same direction. The confounding structures were observed in the stratosphere, where smoke injected at around 15 kilometers in altitude absorbed sunlight and rose further, up to about 35 kilometers of altitude. The rising column of fluid would stretch, causing any residual rotation to get stronger and form vortices.

    None of this was a surprise. What was surprising is that all of the observed vortices were anticyclones, when theory–at least for a heat-driven vortex from a stationary heating source–called for a cyclone-anticyclone pair.

    Researchers looked at how a self-heating (and, therefore, moving) source would rotate. They concluded that this, too, would create a pair of vortices–one cyclonic and one anticyclonic–but the anticyclone would be stronger than the cyclone that trailed behind it. By further considering the vertical shear the vortex pair would encounter, the researchers found that the trailing cyclone could get stripped away, leaving behind only the anticyclone–matching our wildfire observations. (Image credit: J. Stevens/NASA Earth Observatory; research credit: K. Shah and P. Haynes 1, 2; via APS)

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  • Observing Ice Giant Atmospheres

    Observing Ice Giant Atmospheres

    Uranus is one of our solar system’s oddest inhabitants, stuck spinning on its side with a tilted and offset magnetosphere. To better understand it, a team observed the planet for 17 hours with JWST. The near-infrared measurements gave new insight into the planet’s ionosphere, where auroras form. They found that temperatures peaked between 3,000 and 4,000 kilometers, while ion densities peaked at 1,000 kilometers. They also confirmed previous observations that Uranus’s upper atmosphere is cooling down. (Image and video credit: ESA/Webb/NASA/CSA/STScI/P. Tiranti/H. Melin/M. Zamani; research credit: P. Tiranti et al.; via Gizmodo)

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    Recreating Atmospheric Rivers

    During the winter months, those of us living in the mid-latitudes sometimes experience atmospheric rivers. Formed from the interaction of cold winter storms with warm, moist tropical air, atmospheric rivers can deliver intense rainfall across long distances. In this video, the UCLA SpinLab team shows how you can recreate the effect with a relatively simple and affordable DIYnamics apparatus. (Video and image credit: UCLA SpinLab)

  • Jupiter in a Lab

    Jupiter in a Lab

    The vivid bands of a gas giant like Jupiter come from the planet’s combination of rotation and convection. It’s possible to create the same effect in a lab by rapidly spinning a tank of water around a central ice core. That’s the physical set-up behind this research poster–note the illustration in the lower right corner. The central snapshots show how temperature gradients on the water surface change the faster the tank rotates. At higher rotational speeds, the parabolic water surface gets ever steeper and Jupiter-like temperature bands form. (Image credit: C. David et al.)

    Research poster showing how a rotating tank in a lab can develop features that match Jupiter.
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  • Thermal Tides Drive Venusian Winds

    Thermal Tides Drive Venusian Winds

    Venus is a world of extremes. A full rotation of the world takes 243 Earth days, but winds race around the planet at a speed that makes a Category 5 hurricane look sedate. Just what drives these winds has been an ongoing question for planetary scientists. A recent study suggests that tides are a major contributor to this superrotation.

    Unlike Earth’s tides, Venus’s are not gravitational in origin. Instead, Venusian tides are thermal, driven by heating in the sunward side of the atmosphere. This creates a diurnal tide, which cycles once per Venusian day and pumps momentum toward the tops of Venus’s clouds. The new analysis–rooted in both observations and numerical simulation–finds that diurnal tides are the primary driver behind the planet’s incredibly fast winds. (Image credit: NASA/JPL-Caltech; research credit: D. Lai et al.; via Eos)

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  • Panama’s Missing Pacific Upwelling

    Panama’s Missing Pacific Upwelling

    Strong seasonal winds blowing from the Atlantic typically push water away from Panama’s Pacific coast, allowing deeper, colder waters to rise up. This upwelling cools reefs and feeds phytoplankton blooms, both of which support the rich marine life found there. But in early 2025, the upwelling didn’t occur.

    Normally, coastal ocean temperatures drop to about 19 degrees Celsius during upwelling. Instead, temperatures only reached 23.3 degrees at their coolest. Wind seems to be the missing ingredient: winds from the Atlantic side were short-lived and 74% less frequent than in typical years.

    That lack of upwelling is expected to carry consequences to Panama’s economy. About 95% of the country’s fishing catch comes from the Pacific side, so any drop in fish populations will be felt. The open question remains: was the missing upwelling a singular extreme event or a harbinger of a new normal? (Image credit: R. Heuvel; research credit: A. O’Dea et al.; via Eos)

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  • Cloud Convection on Titan

    Cloud Convection on Titan

    Saturn’s moon Titan is a fascinating mirror to our own planet. It’s the only other planetary body with surface-level liquid lakes and seas, but instead of water, Titan’s are made of frigid ethane and methane. Like Earth, Titan has a weather cycle that includes evaporation, condensation, and rain. And now scientists have made their first observations of clouds convecting in Titan’s northern hemisphere.

    Using data from both the Keck Observatory and JWST, the team tracked clouds on Titan rising to higher altitudes, a critical step in the planet’s methane cycle. This translation took place over a period of days, giving scientists modeling the Saturnian moon new insight into the seasonal behaviors of Titan’s atmosphere. (Image credit: NASA/ESA/CSA/STScI; research credit: C. Nixon et al.; via Gizmodo)

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  • A Sprite From Orbit

    A Sprite From Orbit

    A sprite, also known as a red sprite, is an upper-atmospheric electrical discharge sometimes seen from thunderstorms. Unlike lightning, sprites discharge upward from the storm toward the ionosphere. This particular one was captured by an astronaut aboard the International Space Station. That’s a pretty incredible feat because sprites typically only last a millisecond or so. The first one wasn’t photographed until 1989. (Image credit: NASA; via P. Byrne)

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  • Inside Hail Formation

    Inside Hail Formation

    Conventional wisdom suggests that hailstones form over the course of repeated trips up and down through a storm, but a new study suggests that formation method is less common than assumed. Researchers studied the isotope signatures in the layers of 27 hailstones to work out each stone’s formation history. They found that most hailstones (N = 16) grew without any reversal in direction. Another 7 only saw a single period when upwinds lifted them, and only 1 of the hailstones had cycled down-and-up more than once. They did find, however, that hailstones larger than 25mm (1 inch) in diameter had at least one period of growth during lifting.

    So smaller hailstones likely don’t cycle up and down in a storm, but the largest (and most destructive) hailstones will climb at least once before their final descent. (Image credit: D. Trinks; research credit: X. Lin et al.; via Gizmodo)

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  • Climate Change and the Equatorial Cold Tongue

    Climate Change and the Equatorial Cold Tongue

    A cold region of Pacific waters stretches westward along the equator from the coast of Ecuador. Known as the equatorial cold tongue, this region exists because trade winds push surface waters away from the equator and allow colder, deeper waters to surface. Previous climate models have predicted warming for this region, but instead we’ve observed cooling — or at least a resistance to warming. Now researchers using decades of data and new simulations report that the observed cooling trend is, in fact, a result of human-caused climate changes. Like the cold tongue itself, this new cooling comes from wind patterns that change ocean mixing.

    As pleasant as a cooling streak sounds, this trend has unfortunate consequences elsewhere. Scientists have found that this cooling has a direct effect on drought in East Africa and southwestern North America. (Image credit: J. Shoer; via APS News)

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