Volcanoes, meteorites, and hurricanes

[Enola_Straight]

Suppose we have an island or underwater volcano explode…like Krakatoa…or a meteorite strike the ocean.

Aside from the initial destructive blast of the eruption/impact, wouldnt the region of ocean water now be super-heated, spawning tremendous hurricanes?

[Darren_Garrison]

Normal volcanoes are way too piddling to do it, but a really large asteroid or comet could.

[watchwolf49]

Not nearly enough water gets super heated … we get tremendous hurricanes when the ENTIRE tropical Atlantic is super heated, not just one little eddy in the Gulf Stream …

[gnoitall]

Back-of-the envelope (Wolfram Alpha) calculations based on quick-n-dirty Google research tells me that the Krakatoa eruption, the largest one recorded in history, released as much total energy as just one second of a middln’ hurricane’s energy flux.

So, for a volcano to pump as much energy out as a hurricane extracts from warm ocean water, it would have to explode continuously for days or weeks on end.

Not just “erupt” and spew rock or lava. Explode. Over and over. For days.

Do not underestimate the energy of millions of square miles of ocean water being warmed by several hundred watts per square meter of solar insolation.

[Novelty_Bobble]

@gnoitall

Back-of-the envelope (Wolfram Alpha) calculations based on quick-n-dirty Google research tells me that the Krakatoa eruption, the largest one recorded in history, released as much total energy as just one second of a middln’ hurricane’s energy flux.

I’m not questioning your maths but if that calculation is even remotely in the right ballpark that is a sobering comparison to make…boggles the mind it does.

[Duckster]

It turns out that the vast majority of the heat released in the condensation process is used to cause rising motions in the thunderstorms and only a small portion drives the storm’s horizontal winds.

[ul]
[li]Method 1) - Total energy released through cloud/rain formation: An average hurricane produces 1.5 cm/day (0.6 inches/day) of rain inside a circle of radius 665 km (360 n.mi) (Gray 1981). (More rain falls in the inner portion of hurricane around the eyewall, less in the outer rainbands.) Converting this to a volume of rain gives 2.1 x 1016 cm3/day. A cubic cm of rain weighs 1 gm. Using the latent heat of condensation, this amount of rain produced gives [/li]
5.2 x 1019 Joules/day or
6.0 x 1014 Watts.

This is equivalent to 200 times the world-wide electrical generating capacity - an incredible amount of energy produced!
[li]Method 2) - Total kinetic energy (wind energy) generated: For a mature hurricane, the amount of kinetic energy generated is equal to that being dissipated due to friction. The dissipation rate per unit area is air density times the drag coefficient times the windspeed cubed (See Emanuel 1999 for details). One could either integrate a typical wind profile over a range of radii from the hurricane’s center to the outer radius encompassing the storm, or assume an average windspeed for the inner core of the hurricane. Doing the latter and using 40 m/s (90 mph) winds on a scale of radius 60 km (40 n.mi.), one gets a wind dissipation rate (wind generation rate) of [/li]
1.3 x 1017 Joules/day or
1.5 x 1012Watts.

This is equivalent to about half the world-wide electrical generating capacity - also an amazing amount of energy being produced!

[/ul]

Either method is an enormous amount energy being generated by hurricanes. However, one can see that the amount of energy released in a hurricane (by creating clouds/rain) that actually goes to maintaining the hurricane’s spiraling winds is a huge ratio of 400 to 1.

http://www.aoml.noaa.gov/hrd/tcfaq/D7.html

[Chronos]

And as usual, scientific notation doesn’t copy-paste correctly. Those numbers should be (using carats instead of superscripts, so they’ll be copyable from here on out)

5.2 x 10^19 Joules/day or
6.0 x 10^14 Watts.

and

1.3 x 10^17 Joules/day or
1.5 x 10^12Watts.