Super Typhoon Haiyan's Intensification and Unusually Warm Sub-Surface Waters

By: Dr. Jeff Masters , 6:25 PM GMT on November 13, 2013

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A remarkable warming of the sub-surface Pacific waters east of the Philippines in recent decades, due to a shift in atmospheric circulation patterns and ocean currents that began in the early 1990s, could be responsible for the rapid intensification of Super Typhoon Haiyan. Hurricanes are heat engines, which means they take heat energy out of the ocean, and convert it to kinetic energy in the form of wind. It's well-known that tropical cyclones need surface water temperatures of at least 26.5°C (80°F) to maintain themselves, and that the warmer the water, and the deeper the warm water is, the stronger the storm can get. Deep warm water is important, since as a tropical cyclone tracks over the ocean, it stirs up cooler water from the depths, potentially reducing the intensity of the storm. When both Hurricane Katrina and Hurricane Rita exploded into Category 5 hurricanes as they crossed over a warm eddy in the Gulf of Mexico with a lot of deep, warm water, the concept of the total heat energy available to fuel a hurricane--the Tropical Cyclone Heat Potential (TCHP)--became one that gained wide recognition. The Pacific Ocean east of the Philippines has the largest area of deep, warm water of anywhere on Earth, and these waters have historically fueled the highest incidence of Category 5 storms of anywhere on the planet. Super Typhoon Haiyan tracked over surface waters that were of near-average warmth, 29.5 - 30.5°C (85 - 87°F.) However, the waters at a depth of 100 meters (328 feet) beneath Haiyan during its rapid intensification phase were a huge 3°C above average, according to Professor I-I Lin of the Department of Atmospheric Science at the National Taiwan University. An analysis by the Japan Meteorological Agency for October showed ocean temperatures 4 - 5°C (7 - 9°F) above average during October (Figure 1). This analysis was from a model. When looking at actual measurements made by the Argo float data in early November, the temperatures in the layer 100 meters below the surface under Haiyan were about 3°C above average, not 4 - 5°C, according to Dr. Lin. As the typhoon stirred this unusually warm water to the surface, the storm was likely able to feed off the heat, allowing Haiyan to intensify into one of the strongest tropical cyclones ever observed.


Figure 1. Modeled departure of temperature from average at a depth of 100 meters in the West Pacific Ocean during October 2013, compared to a 1986 - 2008 average. The track and intensity of Super Typhoon Haiyan are overlaid. Haiyan passed directly over large areas of sub-surface water that were much above average in temperature, which likely contributed to the storm's explosive deepening. While this model showed 4 - 5°C departures from average in October, the actual values were closer to 3°C in early November, according to Argo float data. Image credit: Japan Meteorological Agency.

Why was there such unusually warm sub-surface water?
The sub-surface waters east of the Philippines have warmed dramatically over the past twenty years. According to Pun et al. (2013), "Recent increase in high tropical cyclone heat potential area in the Western North Pacific Ocean", the depth to where ocean temperatures of at least 26°C (79°F) penetrates has increased by 17% since the early 1990s, and the Tropical Cyclone Heat Potential has increased by 13%. The warm-up is due to an increase in the surface winds blowing across the region--the trade winds--which have caused a southward migration and strengthening of the North Equatorial Current (NEC) and the North Equatorial Counter Current (NECC). The strong trade winds have pushed a large amount of water up against the east coast of the Philippines in the past twenty years, resulting in a rate of sea level rise of 10 mm per year--more than triple the global average of 3.1 mm/yr (Figure 2.) This extra sea level rise contributed to the storm surge damage from Super Typhoon Haiyan. Sea level rise data from Legaspi in the Eastern Philippines shows a rise of about 305 mm (12 inches) since 1949. For comparison, global average sea level rose 7.5" (190 mm) since 1901. Part of the rise along the eastern Philippine coast is from tectonic processes--the subsidence of the Philippine plate under the Eurasian plate--but most of it is due to the stronger trade winds piling up warm water along the coast, and the fact that warmer waters expand, raising sea level.


Figure 2. Trend in sea level from satellite altimeter measurements in 1993 - 2010. Black lines are the Sea Surface Height (SSH) in cm from Rio et al. (2009.) Image credit: Qiu, B., and S. Chen, 2012, "Multidecadal sea level and gyre circulation variability in the northwestern tropical Pacific Ocean", Journal of Physical Oceanography 42.1 (2012): 193-206.

Why have the trade winds sped up?
The surface trade winds in the equatorial Pacific are part of the Walker Circulation--a pattern of rising and sinking air along the Equator that the El Nino/La Nina cycle influences. A strong Walker circulation means there is lower pressure over Indonesia, which pulls in more air at the surface along the Equator from the east, increasing the easterly trade winds. As these trade winds strengthen, they pull surface ocean waters away from South America, allowing cold water to upwell to the surface. This is a La Niña-like situation, which takes heat energy out of the atmosphere, putting it into the ocean, keeping global surface temperatures cooler than they would otherwise be. A weakened Walker circulation is the reverse, resulting in weaker trade winds, and a more El Niño-like situation with higher global surface temperatures. As long as the stronger Walker circulation that has been in place since the early 1990s holds, global surface temperatures should stay cooler than they otherwise would be, prolonging the slow-down in global surface warming that has received much attention this year. There may also be a greater chance of super typhoons and higher storm surges affecting the Philippines, due to the warmer sub-surface waters and re-arranged ocean currents. A 2013 paper by L’Heureux et al. notes that the climate models predict that the Walker circulation should weaken (a more El Niño-like situation)--the reverse of what has been observed the past twenty years. The researchers took the observed pressure patterns over the Pacific in recent decades and removed the atmospheric response to the El Niño/La Niña cycle. The resulting pattern they found showed a steady strengthening of the Walker circulation, in concert with global rising temperatures. So, are we seeing a failure of the climate models? Or is the recent speed-up of the Walker circulation a decades-long temporary "speed bump" in the climate system? Time will tell. It is worth pointing out that a just-released paper by British and Canadian researchers shows that the global surface temperature rise of the past 15 years has been greatly underestimated. As discussed at realclimate.org, "The reason is the data gaps in the weather station network, especially in the Arctic. If you fill these data gaps using satellite measurements, the warming trend is more than doubled in the widely-used HadCRUT4 data, and the much-discussed “warming pause” has virtually disappeared."

I appeared on PBS Newshour last night to discuss the linkages between stronger tropical cyclones and climate change, video here.

References
L’Heureux, Michelle L., Sukyoung Lee, and Bradfield Lyon, 2013, "Recent multidecadal strengthening of the Walker circulation across the tropical Pacific", Nature Climate Change 3.6 (2013): 571-576.

Pun, Iam‐Fei, I‐I. Lin, and Min‐Hui Lo, 2013, "Recent increase in high tropical cyclone heat potential area in the Western North Pacific Ocean", Geophysical Research Letters (2013).

Qiu, B., and S. Chen, 2012, "Multidecadal sea level and gyre circulation variability in the northwestern tropical Pacific Ocean", Journal of Physical Oceanography 42.1 (2012): 193-206.

Jeff Masters

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Quoting 375. TropicalAnalystwx13:

Says the guy living in a tropical Florida.


I used to live in the mid-Atlantic too, stop being such a baby! :P
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Quoting 377. HurrMichaelOrl:


That's amazing, considering Tallahassee,FL has been into the teens as early as November 25th, 13F to be exact.


Wouldn't be surprised if they have an earlier teens someday. They were 21 on Nov 9, 1976. That 13 could have been a mid-teens low a week earlier.
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Quoting 381. Astrometeor:


Good luck with those temps hydrus, it got down to 24 here. Have you adjusted to these kinds of lows since your childhood in Florida or are they still a shock?
The first year I was here ( the first week actually ) it went down to -2 degrees..I worked outside for 1 half hour then had to go in..My lungs were burning..Yes, I do much better now.
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Quoting 305. Pallis:
Actually our current civilization has been created by a slow warming trend for the last 12,000 years or so, and has survived some serious cold spells that killed plenty when there were not so many people.

The last couple of thousand years hasn't shown warming...until the last hundred years or so.

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The 0Z GFS has done a complete 360 with next weeks forecast. Big deep trough is gone on this run.

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Quoting 367. hydrus:
I have a dollar that says COOKEVILLE will be at least 5 degrees colder than the 27 listed..it was 14 there this mornin forecast to be 21.


Good luck with those temps hydrus, it got down to 24 here. Have you adjusted to these kinds of lows since your childhood in Florida or are they still a shock?
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hr 78 gfs rel humity

notice streak in sw pushing east ne ward feeding the flow

Member Since: July 15, 2006 Posts: 176 Comments: 55517
Quoting 375. TropicalAnalystwx13:

Says the guy living in a tropical Florida.


I jog in shorts and a t shirt when temps get that low here.
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I was hoping for a cold blast next week but the 0Z GFS went POOF with all the cold air for the US. Go figure.

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Quoting 335. BaltimoreBrian:


Come north to mild Baltimore!

What's the earliest it's been in the teens there? Could it get into the teens tonight?

Hmmm. The earliest it has been in the teens in Wilmington NC was 16 on November 26, 1950.


That's amazing, considering Tallahassee,FL has been into the teens as early as November 25th, 13F to be exact.
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hr 72 sat 00 gfs
Member Since: July 15, 2006 Posts: 176 Comments: 55517
Quoting 351. CybrTeddy:


Wimp.

Says the guy living in a tropical Florida.
Member Since: July 6, 2010 Posts: 113 Comments: 32690
Quoting 371. BaltimoreBrian:
State Farm took care of us after Charley...thank God.
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Quoting 344. Pallis:
Of course it would, but only if it had steering winds to make it move. That would put the trajectory off a bit too. Whole lot of scenarios,like throwing extremely used bowling balls down a warped lane while taking shots with the Hell's Angels. They could end up just about anywhere given the right conditions. Were I a Saudi Prince, I could cloud seed your spice island out of a job. I wouldn't do that of course, even if I was, but the capability is real. Better to wonder what weather would look like if we had never seeded a cloud, because it has been going on so long. Humans have changed the course of the weather forever by sprinkling fancy dust on clouds.
You obviously have a good supplier.
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Quoting 353. KoritheMan:


lmao
You poke fun. That really hurt.I didn't know she had a boyfriend.
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Quoting 367. hydrus:
I have a dollar that says Crossville will be at least 5 degrees colder than the 27 listed..it was 14 there this mornin forecast to be 21.
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370. MTWX
Quoting 367. hydrus:
I have a dollar that says Crossville will be at least 5 degrees colder than the 27 listed..it was 14 there this mornin forecast to be 21.


Think all the lows forecasted tonight are a bit off... We hit our forecasted low (28) an hour ago, and it is still dropping...
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hr 42 building rtn flow

Member Since: July 15, 2006 Posts: 176 Comments: 55517
hr 36 little area over ne gom

00z gfs hr 36
Member Since: July 15, 2006 Posts: 176 Comments: 55517
Quoting 346. Astrometeor:
Cold Clear Atmosphere!

I have a dollar that says COOKEVILLE will be at least 5 degrees colder than the 27 listed..it was 14 there this mornin forecast to be 21.
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Quoting 349. KoritheMan:




There is no evidence that cloud seeding can alter things on the scale of magnitude that you're talking about. It relies almost entirely on preexisting atmospheric parameters to be effective. It's widely used at airports from what I understand, most notably for fog suppression. However, I have yet to come across a study that establishes the use of this technology as promising beyond a mere local effect; even then, it's rather difficult to distinguish the difference between whether or not X event would have occurred naturally without the use of Y.
Yeah, I have to agree with you there. It would be hard to prove that one event took place in just such a manner because of something happening, but when I started reading about the extensive seeding that has been going on for the last 50? years, I was really surprised. Project Popeye was a well funded and documented expenditure that could have changed weather for Turkmenistan, but who cares about that unless it ruins the season in Switzerland.
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Quoting 347. Patrap:
Don't know nuttin' about "sprinkling Clouds", per say save for The 60's scant attempts, but,..

You'd think the Giga-tonnes of Coal Fired CO2 Plants 24/7/365 and the other emitters would alter the atmosphere detrimentally for Centuries,..

CO2 ppm being 400ppm and all.

O snap, wait....!





How dare you enter discussion about something that may increase ocean temperatures, leading to more intense and more numerous tropical cyclones...Please stay on topic
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Quoting 356. beell:

11/13 18Z GFS 2 m surface temps-Valid Wednesday, Nov 20 (156 hrs)

Check out inland FL.
waitin on 00z to start see what it shows I guess
Member Since: July 15, 2006 Posts: 176 Comments: 55517
363. MTWX
Quoting 360. KoritheMan:


Why would you hope that that's wrong? I've already waged my bets on a cold winter. Call it a psychosomatic reaction because I didn't get a hurricane.

Tryin' to keep my sanity here. :)


I like these good cold fronts coming through. Pushes the birds down from Canada. Ready to do some hunting!!
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Quoting 352. TropicalAnalystwx13:

I was just about to answer you. :P

They're not expecting it to, but I wouldn't be surprised. It's crystal clear outside and there's no wind.


The dewpoint at Wilminton airport is 23, and they went up 1 degree last hour. Burgaw may be a better bet!

Brrrrr in Burgaw ;)
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Quoting 360. KoritheMan:


Why would you hope that that's wrong? I've already waged my bets on a cold winter. Call it a psychosomatic reaction because I didn't get a hurricane.

Tryin' to keep my sanity. :)
True that.:)
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Quoting 354. MTWX:


Saw a forecast for a high of 37 degrees here in MS on Tuesday!! (sure it is wrong though, at least I hope...)


Why would you hope that that's wrong? I've already waged my bets on a cold winter. Call it a psychosomatic reaction because I didn't get a hurricane.

Tryin' to keep my sanity here. :)
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Quoting 357. HurrMichaelOrl:


I remember within the last few years noticing a year where NYC didn't officially get below freezing until almost Christmas Day. That is remarkable. Metro DC struggles to get below 20F in an average winter anymore. It does of course, but hardly at all. Downtown Orlando seems to see an annual low right around 32F on average over the last decade, most likely due to urbanization.


I wonder what the freeze frequency used to be before Orlando got big.
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Quoting 345. BaltimoreBrian:
We've had a few years when when haven't had our first freeze until December in inner Baltimore. Also true for Central Park.


I remember within the last few years noticing a year where NYC didn't officially get below freezing until almost Christmas Day. That is remarkable. Metro DC struggles to get below 20F in an average winter anymore. It does of course, but hardly at all. Downtown Orlando seems to see an annual low right around 32F on average over the last decade, most likely due to urbanization.
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356. beell

11/13 18Z GFS 2 m surface temps-Valid Wednesday, Nov 20 (156 hrs)

Check out inland FL.
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Quoting 340. Tazmanian:
boy some of you guys sure dos not no what cold really is try -35 be low now that is cold

this is vary nic beach weather

Link

as long as ya wearing a snowsuit
Member Since: July 15, 2006 Posts: 176 Comments: 55517
354. MTWX
Quoting 290. StormTrackerScott:


Not surprised as this next blast of cold air means business.



Saw a forecast for a high of 37 degrees here in MS on Tuesday!! (sure it is wrong though, at least I hope...)
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Quoting 350. Pallis:
You mean like that time that big guy caught me with his girlfriend and told me I have two choices, "out the window, or down the stairs"? I took the window. 'Let's get this over with', was my reasoning.


lmao
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Quoting 335. BaltimoreBrian:


Come north to mild Baltimore!

What's the earliest it's been in the teens there? Could it get into the teens tonight?

Hmmm. The earliest it has been in the teens in Wilmington NC was 16 on November 26, 1950.

I was just about to answer you. :P

They're not expecting it to, but I wouldn't be surprised. It's crystal clear outside and there's no wind.
Member Since: July 6, 2010 Posts: 113 Comments: 32690
Quoting 332. TropicalAnalystwx13:
It's so cold right now.

26F/-3C outside.


Wimp.
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Quoting 339. KoritheMan:


If it slowed, there would have been less inland wind damage, but more flooding.

At the speed it was moving, there was less flooding, but more wind damage.

Take your pick?
You mean like that time that big guy caught me with his girlfriend and told me I have two choices, "out the window, or down the stairs"? I took the window. 'Let's get this over with', was my reasoning.
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Quoting 344. Pallis:
Of course it would, but only if it had steering winds to make it move. That would put the trajectory off a bit too. Whole lot of scenarios,like throwing extremely used bowling balls down a warped lane while taking shots with the Hell's Angels. They could end up just about anywhere given the right conditions. Were I a Saudi Prince, I could cloud seed your spice island out of a job. I wouldn't do that of course, even if I was, but the capability is real. Better to wonder what weather would look like if we had never seeded a cloud, because it has been going on so long. Humans have changed the course of the weather forever by sprinkling fancy dust on clouds.


Quoting 344. Pallis:
Of course it would, but only if it had steering winds to make it move. That would put the trajectory off a bit too. Whole lot of scenarios,like throwing extremely used bowling balls down a warped lane while taking shots with the Hell's Angels. They could end up just about anywhere given the right conditions. Were I a Saudi Prince, I could cloud seed your spice island out of a job. I wouldn't do that of course, even if I was, but the capability is real. Better to wonder what weather would look like if we had never seeded a cloud, because it has been going on so long. Humans have changed the course of the weather forever by sprinkling fancy dust on clouds.


There is no evidence that cloud seeding/weather modification technology can alter things on the scale of magnitude that you're talking about. It relies almost entirely on preexisting atmospheric parameters to be effective. It's widely used at airports from what I understand, most notably for fog suppression. However, I have yet to come across a study that establishes the use of this technology as promising beyond a mere local effect; even then, it's rather difficult to distinguish the difference between whether or not X event would have occurred naturally without the use of Y.
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348. MTWX
Quoting 281. GTstormChaserCaleb:
Severe weather coming?





SPC is hinting at Sunday afternoon/evening...
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Don't know nuttin' about "sprinkling Clouds", per say save for The 60's scant attempts, but,..

You'd think the Giga-tonnes of Coal Fired CO2 Plants 24/7/365 and the other emitters would alter the atmosphere detrimentally for Centuries,..

CO2 ppm being 400ppm and all.

O snap, wait....!





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Cold Clear Atmosphere!

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We've had a few years when when haven't had our first freeze until December in inner Baltimore. Also true for Central Park.
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Quoting 304. hydrus:

I can help but ask myself if Haiyan tracked 50 miles south across that hot patch of water rather than the 85 degree stuff would it have been even stronger?
Of course it would, but only if it had steering winds to make it move. That would put the trajectory off a bit too. Whole lot of scenarios,like throwing extremely used bowling balls down a warped lane while taking shots with the Hell's Angels. They could end up just about anywhere given the right conditions. Were I a Saudi Prince, I could cloud seed your spice island out of a job. I wouldn't do that of course, even if I was, but the capability is real. Better to wonder what weather would look like if we had never seeded a cloud, because it has been going on so long. Humans have changed the course of the weather forever by sprinkling fancy dust on clouds.
Member Since: Posts: Comments:
Quoting 340. Tazmanian:
boy some of you guys sure dos not no what cold really is try -35 be low now that is cold

this is vary nic beach weather

Link



We had a day of -47C windchill in January. It's actually surprisingly warm, wearing proper winter clothing it feels like it would at -10C. Pretty amazing beach weather I'd say!
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Beautiful cool evening here with temps in the mid to upper 50s. I was noticing that the current temperature in both Crestview, FL and Macon, GA has plummeted to 30F by 10:00pm. Definitely a hard freeze for these locales tonight. Meanwhile, Atlanta is at 40F. Is this a result of the urban heat island effect?
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We are a balmy 28 here! Still colder than what TWC had for the forecast. Their new and "improved" Local on the 8s had a temp of 30 by midnight. Yeah...
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boy some of you guys sure dos not no what cold really is try -35 be low now that is cold

this is vary nic beach weather

Link

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Quoting 333. hydrus:
Haiyan was a monster so bad, that no matter how fast or slow it was moving, there would have been catastrophic damage. However, it could be argued that if she was moving at 8 to 10 mph, the damage from flooding possibly may have killed more people .


If it slowed, there would have been less inland wind damage, but more flooding.

At the speed it was moving, there was less flooding, but more wind damage.

Take your pick?
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Quoting 330. beell:


Heard that also. Would not seem to matter too much if "Departure of temperature from average at a depth of 100 meters in the West Pacific Ocean" was 4-5�C above average at that speed.

Not in any one spot long enough?

I did consider that if sub-surface water at 100 m was 4-5°C above average it would be somwhat warmer above that level.

Signed,
Curious
Will be studying this storm for a long time...Heart ache city with this horrible disaster.
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Quoting 332. TropicalAnalystwx13:
It's so cold right now.

26F/-3C outside.


"Cold"

Meanwhile I'm enjoying my very above average weather at 5C. :P
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Quoting 334. Bluestorm5:


We're supposed to drop to 15 degrees tonight.
We had a few spotty teens around..That is near record low around here for mid Nov...
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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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