Why does ACE not account for storm size?

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WalterWhite
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Why does ACE not account for storm size?

#1 Postby WalterWhite » Sun Mar 26, 2023 9:55 am

ACE is supposed to measure the total kinetic energy produced by hurricanes over a season. It is determined by taking the sum of the squares of the maximum sustained wind speeds of each storm above 35 knots for each 6-hour interval. Its units are square hectoknots.

Kinetic energy is proportional to the MASS TIME THE SQUARE OF VELOCITY. With this in mind, should the ACE metric also account for the size of a storm? Perhaps estimations of the radius and height of a storm can be used to approximate the volume of a storm, which can then be used to approximate the mass of a storm.

Currently, ACE does not distinguish between compact storms and large storms at a given maximum sustained wind speed, even though the two would be very much different in terms of kinetic energy output. Given that kinetic energy is proportional to the mass times velocity squared, should ACE account for this?
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Re: Why does ACE not account for storm size?

#2 Postby Category5Kaiju » Sun Mar 26, 2023 10:25 am

WalterWhite wrote:ACE is supposed to measure the total kinetic energy produced by hurricanes over a season. It is determined by taking the sum of the squares of the maximum sustained wind speeds of each storm above 35 knots for each 6-hour interval. Its units are square hectoknots.

Kinetic energy is proportional to the MASS TIME THE SQUARE OF VELOCITY. With this in mind, should the ACE metric also account for the size of a storm? Perhaps estimations of the radius and height of a storm can be used to approximate the volume of a storm, which can then be used to approximate the mass of a storm.

Currently, ACE does not distinguish between compact storms and large storms at a given maximum sustained wind speed, even though the two would be very much different in terms of kinetic energy output. Given that kinetic energy is proportional to the mass times velocity squared, should ACE account for this?


I believe there is a metric called TIKE that does something like this
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Re: Why does ACE not account for storm size?

#3 Postby captainbarbossa19 » Mon Mar 27, 2023 7:27 am

Category5Kaiju wrote:
WalterWhite wrote:ACE is supposed to measure the total kinetic energy produced by hurricanes over a season. It is determined by taking the sum of the squares of the maximum sustained wind speeds of each storm above 35 knots for each 6-hour interval. Its units are square hectoknots.

Kinetic energy is proportional to the MASS TIME THE SQUARE OF VELOCITY. With this in mind, should the ACE metric also account for the size of a storm? Perhaps estimations of the radius and height of a storm can be used to approximate the volume of a storm, which can then be used to approximate the mass of a storm.

Currently, ACE does not distinguish between compact storms and large storms at a given maximum sustained wind speed, even though the two would be very much different in terms of kinetic energy output. Given that kinetic energy is proportional to the mass times velocity squared, should ACE account for this?


I believe there is a metric called TIKE that does something like this


It was difficult to find the acronym online, but it looks like the "I" stands for integrated. If that is the case, then that would make sense that this metric would be used to account for the storm's size total KE output.
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Re: Why does ACE not account for storm size?

#4 Postby wxman57 » Mon Mar 27, 2023 1:42 pm

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Re: Why does ACE not account for storm size?

#5 Postby 1900hurricane » Tue Mar 28, 2023 8:55 pm


It's been a while since I used that first page. I remember testing it out and comparing to my script to calculate Integrated Kinetic Energy myself years ago. Turns out, there was actually a bug in that calculator related to the largest TS wind radius. I'll have to see if I can replicate it when I get a chance because I didn't email them at the time in 2018, so I imagine it's still there. I remember using operational Mangkhut wind radii to trigger it.

Regarding Track Integrated Kinetic Energy, it has the right spirit...but the execution is sorely lacking. It's kind of sad when sloppy early season tropical storms end up with a higher metric than Eta, the storm that literally generated the highest storm tide in the entire basin. And that's even ignoring the physical ramifications of the metric. We're obviously dealing with kinetic energy, but over what time period is the energy measured/derived? Is it for the duration of the sustained wind? Maybe over the 6 hour period between best track points. Like I said, great idea, but it just doesn't seem like a well thought out metric with any meaning to it.
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