Гипотетикалық супердайырл (Gipotétikalık superdayırl)

Hypothetical class of extreme tropical cyclone

A hypercane is a hypothetical class of extreme tropical cyclone that could form if sea surface temperatures reached approximately 50 °C (122 °F), which is warmer than the warmest ocean temperature ever recorded. Such an increase could be caused by a large asteroid or comet impact, a large supervolcanic eruption, a large submarine flood basalt, or "incredible" global warming. There is some speculation that a series of hypercanes resulting from the impact of a large asteroid or comet contributed to the demise of the non avian dinosaurs.

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, 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. For comparison, the largest and most intense storm on record was 1979's Typhoon Tip, 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, 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.

A hurricane functions as a Carnot heat engine 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 from evaporating sea water, which is then released as sensible heat 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 close to the surface, which leads to an energy balance equilibrium. In Emanuel's model, if the temperature difference between the sea and the top of the troposphere 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, whether shock waves would form in the outflow around the eye, or whether turbulent breakdown of the vortex happens.