Hypercane
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A hypercane is a hypothetical class of extreme
tropical cyclone A tropical cyclone is a rapidly rotating storm system characterized by a low-pressure center, a closed low-level atmospheric circulation, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain and squalls. Depend ...
that could form if sea surface temperatures reached approximately , which is warmer than the warmest ocean temperature ever recorded. Such an increase could be caused by a large
asteroid An asteroid is a minor planet of the inner Solar System. Sizes and shapes of asteroids vary significantly, ranging from 1-meter rocks to a dwarf planet almost 1000 km in diameter; they are rocky, metallic or icy bodies with no atmosphere. ...
or
comet A comet is an icy, small Solar System body that, when passing close to the Sun, warms and begins to release gases, a process that is called outgassing. This produces a visible atmosphere or coma, and sometimes also a tail. These phenomena ar ...
impact, a large supervolcanic eruption, anthropogenic
climate change In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to E ...
, or a large submarine
flood basalt A flood basalt (or plateau basalt) is the result of a giant volcanic eruption or series of eruptions that covers large stretches of land or the ocean floor with basalt lava. Many flood basalts have been attributed to the onset of a hotspot reach ...
. There is some speculation that a series of hypercanes resulting from the
impact Impact may refer to: * Impact (mechanics), a high force or shock (mechanics) over a short time period * Impact, Texas, a town in Taylor County, Texas, US Science and technology * Impact crater, a meteor crater caused by an impact event * Impact ...
of a large asteroid or comet contributed to the
demise Demise is an Anglo-Norman legal term (from French ''démettre'', from Latin ''dimittere'', to send away) for the transfer of an estate, especially by lease. It has an operative effect in a lease, implying a covenant "for quiet enjoyment." The ...
of the non-avian
dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...
s. The hypothesis was created by
Kerry Emanuel Kerry Andrew Emanuel (born April 21, 1955) is an American professor of meteorology currently working at the Massachusetts Institute of Technology in Cambridge. In particular he has specialized in atmospheric convection and the mechanisms acting t ...
of
MIT The Massachusetts Institute of Technology (MIT) is a private land-grant research university in Cambridge, Massachusetts. Established in 1861, MIT has played a key role in the development of modern technology and science, and is one of the mo ...
, who also coined the term. Additionally, it is also speculated that many planets that could orbit red dwarf stars, if they have liquid water, would permanently experience hypercanes on their sunlit faces due to the effects of tidal locking. This could potentially challenge any life forms that were to live there.


Description

In order to form a hypercane, according to Emanuel's hypothetical model, the ocean temperature would have to be at least 49 °C (120 °F). A critical difference between a hypercane and present-day hurricanes is that a hypercane would extend into the upper
stratosphere The stratosphere () is the second layer of the atmosphere of the Earth, located above the troposphere and below the mesosphere. The stratosphere is an atmospheric layer composed of stratified temperature layers, with the warm layers of air ...
, whereas present-day hurricanes extend into only the lower stratosphere. Hypercanes would have wind speeds of over , potentially gusting to , and would also have a central pressure of less than , giving them an enormous lifespan of at least several weeks. This extreme low pressure could also support massive storm systems roughly the size of North America. For comparison, the largest and most intense storm on record was 1979's
Typhoon Tip Typhoon Tip, known in the Philippines as Typhoon Warling, was the largest and most intense tropical cyclone ever recorded. The forty-third tropical depression, nineteenth tropical storm, twelfth typhoon, and third super typhoon of the 1979 Paci ...
, with a 1-minute sustained wind speed of and a minimum central pressure of . Such a storm would be nearly eight times more powerful than
Hurricane Patricia Hurricane Patricia was the strongest tropical cyclone on record worldwide in terms of wind speed and the second-most intense on record worldwide in terms of pressure, behind Typhoon Tip in 1979, with a minimum atmospheric pressure of 872 mbar ( ...
, the storm with the highest sustained wind speed recorded, which had 1-minute sustained winds of 345 km/h (215 mph). However, hypercanes may be as small as in size, and they would lose strength quickly after venturing into colder waters. The waters after a hypercane could remain hot enough for weeks, allowing more hypercanes to form. A hypercane's clouds would reach into the
stratosphere The stratosphere () is the second layer of the atmosphere of the Earth, located above the troposphere and below the mesosphere. The stratosphere is an atmospheric layer composed of stratified temperature layers, with the warm layers of air ...
. Such an intense storm would also damage the Earth's
ozone layer The ozone layer or ozone shield is a region of Earth's stratosphere that absorbs most of the Sun's ultraviolet radiation. It contains a high concentration of ozone (O3) in relation to other parts of the atmosphere, although still small in rela ...
, potentially having devastating consequences for life on Earth. Water molecules in the stratosphere would react with
ozone Ozone (), or trioxygen, is an inorganic molecule with the chemical formula . It is a pale blue gas with a distinctively pungent smell. It is an allotrope of oxygen that is much less stable than the diatomic allotrope , breaking down in the lo ...
to accelerate decay into O2 and reduce absorption of
ultraviolet light Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30  PHz) to 400 nm (750  THz), shorter than that of visible light, but longer than X-rays. UV radiation i ...
.


Mechanism

A hurricane functions as a
Carnot heat engine A Carnot heat engine is a heat engine that operates on the Carnot cycle. The basic model for this engine was developed by Nicolas Léonard Sadi Carnot in 1824. The Carnot engine model was graphically expanded by Benoît Paul Émile Clapeyron in 1 ...
powered by the temperature difference between the sea and the uppermost layer of the troposphere. As air is drawn in towards the eye it acquires
latent heat Latent heat (also known as latent energy or heat of transformation) is energy released or absorbed, by a body or a thermodynamic system, during a constant-temperature process — usually a first-order phase transition. Latent heat can be understo ...
from evaporating sea-water, which is then released as
sensible heat Sensible heat is heat exchanged by a body or thermodynamic system in which the exchange of heat changes the temperature of the body or system, and some macroscopic variables of the body or system, but leaves unchanged certain other macroscopic vari ...
during the rise inside the eyewall and radiated away at the top of the storm system. The energy input is balanced by energy dissipation in a turbulent
boundary layer In physics and fluid mechanics, a boundary layer is the thin layer of fluid in the immediate vicinity of a bounding surface formed by the fluid flowing along the surface. The fluid's interaction with the wall induces a no-slip boundary condi ...
close to the surface, which leads to an energy balance equilibrium. However, in Emanuel's model, if the temperature difference between the sea and the top of the
troposphere The troposphere is the first and lowest layer of the atmosphere of the Earth, and contains 75% of the total mass of the planetary atmosphere, 99% of the total mass of water vapour and aerosols, and is where most weather phenomena occur. From ...
is too large, there is no solution to the equilibrium equation. As more air is drawn in, the released heat reduces the central pressure further, drawing in more heat in a runaway positive feedback. The actual limit to hypercane intensity depends on other energy dissipation factors that are uncertain: whether inflow ceases to be
isothermal In thermodynamics, an isothermal process is a type of thermodynamic process in which the temperature ''T'' of a system remains constant: Δ''T'' = 0. This typically occurs when a system is in contact with an outside thermal reservoir, and a ...
, whether
shock waves In physics, a shock wave (also spelled shockwave), or shock, is a type of propagating disturbance that moves faster than the local speed of sound in the medium. Like an ordinary wave, a shock wave carries energy and can propagate through a med ...
would form in the outflow around the
eye Eyes are organs of the visual system. They provide living organisms with vision, the ability to receive and process visual detail, as well as enabling several photo response functions that are independent of vision. Eyes detect light and conv ...
, or whether turbulent breakdown of the vortex happens.


See also

*
Global catastrophic risk A global catastrophic risk or a doomsday scenario is a hypothetical future event that could damage human well-being on a global scale, even endangering or destroying modern civilization. An event that could cause human extinction or permanen ...
*
Saffir–Simpson scale The Saffir–Simpson hurricane wind scale (SSHWS) classifies hurricanes—which in the Western Hemisphere are tropical cyclones that exceed the intensities of tropical depressions and tropical storms—into five categories distinguished by ...
*
Tornado A tornado is a violently rotating column of air that is in contact with both the surface of the Earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud. It is often referred to as a twister, whirlwind or cyclone, altho ...
*
Extraterrestrial cyclone An extraterrestrial vortex is a vortex that occurs on planets and natural satellites other than Earth that have sufficient atmospheres. Most observed extraterrestrial vortices have been seen in large cyclones, or anticyclones. However, occasional d ...
*
Great Red Spot The Great Red Spot is a persistent high-pressure region in the atmosphere of Jupiter, producing an anticyclonic storm that is the largest in the Solar System. Located 22 degrees south of Jupiter's equator, it produces wind-speeds up to 432  ...
*
Great Dark Spot The Great Dark Spot (also known as GDS-89, for Great Dark Spot, 1989) was one of a series of dark spots on Neptune similar in appearance to Jupiter's Great Red Spot. In 1989, GDS-89 was the first Great Dark Spot on Neptune to be observed by NASA ...


References

{{Cyclones


External links


Hypercanes: The Next Big Disaster Movie?
– YouTube Tropical cyclone meteorology Weather hazards Doomsday scenarios Geological hazards Future problems Meteorological hypotheses