Record-breaking ocean heat fueled Hurricane Harvey
Ocean evaporation matched up with massive overland rainfall
BOULDER, Colo. — In the weeks before Hurricane Harvey tore across the Gulf of Mexico and plowed into the Texas coast in August 2017, the Gulf’s waters were warmer than any time on record, according to a new analysis led by the National Center for Atmospheric Research (NCAR).
These hotter-than-normal conditions supercharged the storm, fueling it with vast stores of moisture, the authors found. When it stalled near the Houston area, the resulting rains broke precipitation records and caused devastating flooding.
“We show, for the first time, that the volume of rain over land corresponds to the amount of water evaporated from the unusually warm ocean,” said lead author Kevin Trenberth, an NCAR senior scientist. “As climate change continues to heat the oceans, we can expect more supercharged storms like Harvey.”
Despite a busy 2017 hurricane season, Hurricane Harvey was more or less isolated in location and time, traveling solo over relatively undisturbed waters in the Gulf of Mexico. This gave Trenberth and his colleagues an opportunity to study in detail how the storm fed off the heat stored in that 930-mile wide ocean basin.
The team compared temperatures in the upper 160 meters (525 feet) of the Gulf before and after the storm using data collected by Argo, a network of autonomous floats that measure temperature as they move up and down in the water. To measure rainfall over land, the scientists took advantage of a new NASA-based international satellite mission, dubbed Global Precipitation Measurement.
The study appears in the journal Earth’s Future, a publication of the American Geophysical Union. It was funded by the U.S. Department of Energy and by the National Science Foundation, which is NCAR’s sponsor. Other co-authors of the paper are Yongxin Zhang and John Fasullo, also of NCAR; Lijing Cheng, of the Chinese Academy of Sciences; and Peter Jacobs, of George Mason University.
Matching evaporation and rain
As hurricanes move over the ocean, their strong winds strafe the sea surface, making it easier for water to evaporate. The process of evaporation also requires energy from heat, and the warmer the temperatures are in the upper ocean and at the ocean surface, the more energy is available.
As the storm progresses over the ocean, evaporating water as it goes, it leaves a cold wake in its path. In the case of Hurricane Harvey, the scientists found the cold wake was not very cold. So much heat was available in the upper layer of the ocean that, as the surface temperature was cooled from the storm, heat from below welled up, rewarming the surface waters and continuing to feed the storm.
The near-surface ocean temperature before the storm’s passage was upward of 30 degrees Celsius (86 degrees Fahrenheit), and after passage the temperature was still around 28.5 C (83 F). Sea surface temperatures above 26 C (79 F) are typically needed for a hurricane to continue to grow.
Even after Harvey made landfall, its arms reached out over the ocean, continuing to draw strength (and water) from the still-warm Gulf.
“The implication is that the warmer oceans increased the risk of greater hurricane intensity and duration,” Trenberth said. “While we often think of hurricanes as atmospheric phenomena, it’s clear that the oceans play a critical role and will shape future storms as the climate changes.”
The scientists were able to measure the total loss in ocean heat, mostly due to evaporation, as the storm moved over the Gulf. They also measured the latent heat released over land as the water vapor turned back into liquid water and fell as rain. They then compared those two measurements and found that they corresponded.
The study highlights the increased threat of future supercharged hurricanes due to climate change, Trenberth said.
“We know this threat exists, and yet in many cases, society is not adequately planning for these storms,” Trenberth said. “I believe there is a need to increase resilience with better building codes, flood protection, and water management, and we need to prepare for contingencies, including planning evacuation routes and how to deal with power cuts.”
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From the NATIONAL CENTER FOR ATMOSPHERIC RESEARCH/UNIVERSITY CORPORATION FOR ATMOSPHERIC RESEARCH
About the study
Title: Hurricane Harvey Links to Ocean Heat Content and Climate Change Adaptation
Authors: Kevin E. Trenberth, Lijing Cheng, Peter Jacobs, Yongxin Zhang, and John Fasullo
Journal: Earth’s Future
Counterpoint:
Alarmists Resurrect Dubious Claim That Global Warming Fueled Hurricane Harvey’s Record Rainfall
http://dailycaller.com/2018/05/09/alarmists-claim-global-warming-fueled-hurricane-harvey/
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“In the weeks before Hurricane Harvey tore across the Gulf of Mexico and plowed into the Texas coast in August 2017, the Gulf’s waters were warmer than any time on record, according to a new analysis led by the National Center for Atmospheric Research (NCAR).”
When we consider that the mixed layer is at foremost involved in the atmosphere-ocean interaction when it comes to hurricans we should look at the SST of this region. According to the ERSSTv5 dataset this gives this picture for the time span 1900 to 2017:
There is much internal variability (AMO). It’s influence on the hurricans is well known from the literature.
The gulf- SST in august were warmer than 2017 in the following years: 1941; 1958; 1962; 1998; 2010; 2011; 2015; 2016.
IMO the cited claim should be rejected.
PS: I forgot 2005, sorry!
If K. Treberth is correct then organic life is a zero sum game, or it must be for energy in to equal energy out.
How does that square with and expanding human population?
Oops porof-raeding failrue again —
Should be —
How does that square with an expanding human population?
I do not doubt the unprecedented high rainfall totals for the greater Houston area.
A stalled out rainmaker like Harvey on a coastal region can do that in late August.
I do not doubt that northern Gulf SST was anomalously high in late August 2017.
No hurricanes had traversed those waters since Hurricane Ike in 2008.
Now You be the judge.
Argo floats in the Gulf.
http://i67.tinypic.com/2d6ulit.jpg
And the rainfall bands that fed in water from the Gulf between the critical days of 26-28 August.
https://m.youtube.com/watch?v=JT8x0Dmn7O8
Mann “post-predicted” Harvey’s flooding was caused by Man-made “Climate Change”.
Trenberth claims the Man-made “missing heat” finally showed up in Harvey.
We need one more Man-made Harvey claim for a losing Trifecta!
” .. said lead author Kevin Trenberth, an NCAR senior scientist. “As climate change continues to heat the oceans, we can expect more supercharged storms like Harvey.” …”
—-
Yeah right, not like that happened for every major cyclone during the Holocene. Oil that squeaky-wheel.
The surface temperature is of course intresting, but a minor part in the energy flow.
It takes 2260 kJ to convert a kilogram of liquid water into gaseous water vapour.
To warm a kilogram of liquid water, from 26 to 30 C, the enegy needed is 17 kJ.
The “SST” are taken in a depth of about 5…10m. The mixed layer during summer is reaching down to 15m, see http://www.revistascca.unam.mx/atm/index.php/atm/article/view/8542/8012 . That means that the upper 15m of the gulf have the same temperature shown in the figure above. SST is NOT the skin-temperature! 15m water depth should be enough to estimate the energy flowing to the atmosphere?
…“We know this threat exists, and yet in many cases, society is not adequately planning for these storms,” Trenberth said. “I believe there is a need to increase resilience with better building codes, flood protection, and water management, …
Hang on a second! When this Climate Change scare started, you said we had to prepare for hot, dry conditions….
Trenberth, the man who blatantly lied to me about his mate Phil Jones. The man who claimed the “evidence” for man caused global warming is sea levels.
Who in their right mind would believe anything he says?
Can you fill us in on the details of 1st statement?
I wonder, what is new news in this? Cyclonic activity covers cold clouds hundreds of square kilometers and thus bring down the temperature on waters or on land.
Dr. S. Jeevananda Reddy
It’s clear that global warming will result in bigger storms and greater rainfall. Time for cities, counties and states to prepare.
I once asked a meteorologist who had studied hurricanes if upwelling could be a factor in weakening of storms. This was after Hurricane Allen in 1980 which pulsated but pressure was rising at landfall. The cautious answer was that dust could do this, S Texas and N Mexico with plenty. The continental shelf gets thinner as you go down the Texas coast and it is not rare that summer beach temperatures are cooler off Brownsville (Allen strike area) than Corpus Christi, about two degrees of latitude farther north. Claudette in 2003 went in on the middle coast at Pt. O’Connor and strengthened right on the coast going from a low 1 to a high 1 or maybe a low 2. It then headed towards California, not exactly typical.
Hurricane Allen was back in the days before ‘scientists’ became saviours preaching in their papers. I am sitting here in Harvey land watching structures go up, some dumb, some smart, problem is not science, but engineering and politics.
Great, as the NH hurricane season approaches, the hurricane scare-mongering season gets underway. Be afraid, be very afraid.
“As climate change continues to heat the oceans,…”
Climate CHANGE heats the oceans?
Isn’t it the other way around?
Trenberth, the Flat Earth man. Not just flat, but non rotating, too. And homogenous.
The wonder is, some people still care about what he says.
Hell, if this man keeps his budget the way he figures Earth’s energy budget, he sure filled bankrupcy. I bet he doesn’t.
I do like Trenberth’s classic Global energy balance chart. Give the guy credit. You can show someone rather easily how insignificant a couple of watts of CO2 IR is compared to 80 watts of water evaporation, and that IR heat loss from ground to sky, surface emission minus back IR, is less than evaporation heat loss. You can even use it to show someone how much change in albedo due to extra clouds, the result of additional evaporation, would counteract the additional CO2 warming effect. All in all, a handy tool to bring warming hypists back to reality, using info from their own hero. Willis Eschenbach’s version of it is better.
https://wattsupwiththat.com/2017/11/24/can-a-cold-object-warm-a-hot-object/
I am surprised that Trenberth commented on “we think of hurricanes as being atmospheric phenomena”. I believe it has ALWAYS been known widely that they are stimulated by relatively warm patches of water and that the water over which they move is cooled, hence the result that no two cyclones/hurricanes will follow exactly the same path in any short period of time.
He should also understand, but doesn’t want to, that the development of a cyclone depends on temperature differences across the water, NOT simply a general overall high temperature which they believe will come with “Global Warming” .No wonder the AGTW crowd always gets it so wrong!!! .
So, all of the “missing heat” is located in the North Atlantic? Not the Pacific, Indian Ocean, or South Atlantic?
Does Trenberth imply that these events will be more frequent because my analysis has showed that this El Niño of 2015 was entirely predictable. This same El Niño occurs every 60 years in the record at the same point in the pdo/amo 60 year cycle. Right about the middle of the downward leg of the cycle a huge El Niño occurs. I even predicted it.
According to my reading of the pdo/amo cycle we now have 15 more years of relatively slightly cooler temperatures before we will see another large El Niño.