Hurricanes Might Not Be Losing Steam As Fast As They Used To (arstechnica.com) 20
An anonymous reader quotes a report from Ars Technica: [A] new study [published in the journal Nature] by Lin Li and Pinaki Chakraborty at the Okinawa Institute of Science and Technology Graduate University focuses on a less-than-obvious question: what happens to hurricanes after landfall in a warming world? Once a storm moves over land, it loses the water vapor from warm ocean waters that fuel it, so it rapidly weakens. The total damage done depends in part on how quickly it weakens. The researchers examined a data set of all North Atlantic landfalling hurricanes between 1967 and 2018. The primary metric they were interested in was the rate the hurricane lost strength over the first 24 hours after landfall. Strength "decays" on an exponential curve, so they boiled this down to a mathematical parameter for decay time.
This parameter varies a fair bit from storm to storm depending on weather conditions and terrain, so the researchers compared averages for each half of the 50-year period. They found a pretty strong trend. In the earlier 25-year period, the average storm lost about 75 percent of its strength over the first day. In the latter half, the average storm lost only half of its strength. The researchers also analyzed sea surface temperatures in this area, which have obviously increased over the last 50 years. That means there's a rough correlation between warmer ocean temperatures and hurricanes retaining strength after landfall. But is there a physical reason to believe the former caused the latter?
To test this, the researchers used a computer-model simulation of an idealized hurricane -- that is, a hurricane in a homogenous virtual setting rather than above a specific location on the Earth. They simulated a series of hurricanes over increasingly warm water, with intensity capped at Category 4, and had each one make landfall at exactly the same strength. Landfall was simulated by suddenly cutting off the supply of water vapor at the bottom of the storm. Sure enough, the storms that had grown over a warmer ocean took longer to weaken. That means this isn't a matter of, say, the back half of a storm still feeding on warm water while the front half crosses onto land. Instead, it appears that increased water vapor entrained within the storm itself helped sustain it. Another set of simulations confirmed this by also removing the water vapor at landfall -- in this case, the storms all weakened identically.
This parameter varies a fair bit from storm to storm depending on weather conditions and terrain, so the researchers compared averages for each half of the 50-year period. They found a pretty strong trend. In the earlier 25-year period, the average storm lost about 75 percent of its strength over the first day. In the latter half, the average storm lost only half of its strength. The researchers also analyzed sea surface temperatures in this area, which have obviously increased over the last 50 years. That means there's a rough correlation between warmer ocean temperatures and hurricanes retaining strength after landfall. But is there a physical reason to believe the former caused the latter?
To test this, the researchers used a computer-model simulation of an idealized hurricane -- that is, a hurricane in a homogenous virtual setting rather than above a specific location on the Earth. They simulated a series of hurricanes over increasingly warm water, with intensity capped at Category 4, and had each one make landfall at exactly the same strength. Landfall was simulated by suddenly cutting off the supply of water vapor at the bottom of the storm. Sure enough, the storms that had grown over a warmer ocean took longer to weaken. That means this isn't a matter of, say, the back half of a storm still feeding on warm water while the front half crosses onto land. Instead, it appears that increased water vapor entrained within the storm itself helped sustain it. Another set of simulations confirmed this by also removing the water vapor at landfall -- in this case, the storms all weakened identically.
But, but, teh storm count!!1 (Score:2)
The storm count hasn't increased you know! Please ignore inflation-adjusted damage amounts, intensity and all other factors. This is an important talking point my brain has downloaded from conspiracy blogs.
Re:Global warming (Score:5, Insightful)
And, you know, have taken measurements of recent global average temperatures, CO2 levels, wildfire area, etc, but why let a nasty bit of science and objective reality get in the way of blind political dogma? The free market can't solve it so it's not real!
Oh wait, what's that, renewable energy is cheaper than fossil energy now? Well we've made political enemies of the renewable energy CEOs and we're still very much in bed with the fossil energy CEOs so it's still not real! LALALALA I can't hear you!
Re: (Score:2)
Except the free market IS SOLVING it. Actually its about the only thing that is. Turns out people like like clean air, water, etc and are willing to pay more for clean energy, more efficient products, greener service providers etc.
You know we have reduced emissions under Trump right? That isn't a function of regulations, its function of the marketplace choosing cleaner greener options, all on its own.
Re:Global warming (Score:5, Insightful)
Would've happened a lot faster if politicians weren't subsidizing and promoting fossil fuels and in some cases fighting the switch to renewable energy, as the dear orange leader has done.
Re: (Score:2)
I agree with that. I don't consider subsidies, "free market'
Re: (Score:1)
how the fuck is this +4 "insightful"?
It isn't real. They fucked up the study. Maybe try READING it first, eh?
Re: (Score:1)
Re: (Score:2)
I fully agree that closing nuclear power plants is a terrible idea, but this doesn't mean that renewables + storage isn't the cheapest option overall for new power generation:
https://www.pv-tech.org/news/s... [pv-tech.org]
Making and mining the materials for renewable energy technology are nothing compared to fossil fuel mining and refining - and these produce vast quantities of waste too. Waste ponds, sulfur ziggurats, fly ash lakes, the occasional oil spill, coal power plants sprinkling plumes of exhaust containing radi
Turns out... (Score:2)
...they've really started to like Team Fortress 2.
"Losing steam" ? Really ? (Score:1)
Did the author think that "losing steam" was a good metaphor to use here, one that wouldn't be atall confusing ?
Did the editor ?
All crows are white (Score:1)
I saw a white crow today. Therefore, crows must be becoming white.
They had an oopsie... (Score:1)
It seems the researchers "forgot" to remove all the storms that made landfall and then turned back out to sea...
Quite the tweet storm forming over that.
what is "strenght"? (Score:2)
Anyway, if strength is say wind speed and it depends on the amount of moisture, in the past 60 years, the climate became noticeably wetter because of global warming, which could mean that wetness drops to "threshold" level slower than in the past.
Seriously, go shopping to NOAA FTP side and check out their precipitation data. You will see noticeable trends towards wetness in many places.
For example, Sahara moves up, which means that it actually decreases in area.
Is this the new spin? (Score:2, Interesting)
"Global Warming will make storms worse!"
(a number of QUIETER than normal years stormwise)
"Well we may have fewer storms, but they're going to be MORE INTENSE - for sure!"
(storm intensities measured by historical standards don't really change beyond the 'noise' of normal variation)
"Well, they may not have really gotten more intense, but look at all the $BILLIONS in damage where they used to do $MILLIONS!"
(studies correcting for property values to current dollars, and then correcting for new additional proper
Re: (Score:1)
More energy is available (Score:2)