As I’ve written before, hurricanes are natural heat engines. They transport surface heat to the upper atmosphere for dissipation to space. They do a splendid job of cooling the ocean surface over which they travel.
In the animation above from NASA SVS: As water vapor evaporates from the warm ocean surface, it is forced upward in the convective clouds that surround the eyewall and rainband regions of a storm. As the water vapor cools and condenses from a gas back to a liquid state, it releases latent heat. The release of latent heat warms the surrounding air, making it lighter and thus promoting more vigorous cloud development.
Hurricane Igor is another example. I’ve created an animation show what it has done to sea surface temperature after passage. Note there is a pause at the beginning and end of the animation. Note the annotations in the Atlantic.
I have a larger version of the animation here.
Here’s a close up view of the Atlantic off the USA east coast. The effect from Igor is evident.
At the center of the storm track, SST’s were dropped as much as 3°C
Here’s another animation:
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Really Cool! Anthony . WHUT happens when there is no warm to abate?
Joe B. has a nice video on AccuWeather:
http://www.accuweather.com/video/73146202001/the-reason-for-the-season-and-why-i-wasnt-teasin.asp
@ur momisugly 5:50 to 7:00 See cold SST along Igor’s path
Hey, now that is quite impressive! Always thought that cooling occurred but never got the chance to actually view it. Seem my comment last article of -5 ºC is a twice too high, more like 2½ ºC but gone within two weeks. Filing upstairs.
Thanks for the science Anthony.
Igor spare Bermuda, bite Newfoundland.
Me make cool pics.
http://www.cbc.ca/nl/blogs/seen/stormcentre.html
I assume this phenomenon is in the models…
Igor forgot to say: Scroll down on last link for pics. Me scary.
Nasty weather in Newfoundland, remind me of a particularly nasty Sou’Wester we had a few
years back in Coos Bay, Or…
Clearly that cooling is happening,nice post Anthony..
And this is supposed to be a surprise? It’s what hurricanes do.
REPLY: Ah, John, you are extrapolating without actual data; the word “surprise” is not mentioned. I just find it interesting. My business is weather, I’ve reported on it for 30 years now and still do daily. This report is no different than what I’d do on the evening news, offering some lighthearted education on recent weather events. You are entitled to your opinion, but I’ll report what I like here. In fact one of our readers requested this feature again for Igor, but I don’t recall a request for additional snark.- Anthony
I wonder how much cooling might be due to upwelling advection of cooler deep water around the periphery of these storms as the upper layer of the ocean is sucked in to the center of the storm and made subject rapid evaporation from the action of high velocity winds. Perhaps this would only be an appreciable factor on storms of the very highest intensity.
Thanks for the graphics, well done. They will be useful to explain to others what I am talking about.
I said “gone” in two weeks above about the cooling and it would have been better worded as dispersed, mixed, or smoothed out for hundreds of miles which is actually what happens.
I may have this completely wrong. I read that the sea surface can rise up eight meters under the eye of the storm. This is quite a little hill! I would expect the water at the top to flow down hill with cooler water upwelling in the middle. Most of the vaporisation being due to the intense pressure drop. This does not effect the latent heat transport to the upper atmosphere.
“Spector says:
September 24, 2010 at 10:16 pm
I wonder how much cooling might be due to upwelling advection of cooler deep water around the periphery of these storms as the upper layer of the ocean is sucked in to the center of the storm and made subject rapid evaporation from the action of high velocity winds. Perhaps this would only be an appreciable factor on storms of the very highest intensity.”
I’ve really thought on that aspect since the last article. We know the low pressure near the eye lifts the water but I’m not sure it actually creates an inward flow of the surface water from the edges. If it did, that would create a steady flow inward along the surface to the eye and downward to some x depth and there outward back to the edges with the upwelling you speak of.
But that would mean the cooling is being much deeper than merely few meters of the surface. You don’t seems to see this deep cooling for it dissipates as you see in the animations above in a matter of weeks. Don’t know if it could disappear that fast if it was cooled thoroughly 50 to 100 meters deep by this torus shaped cyclic flow.
The other way would be the low pressure just lifts creating an upper slope or hump on the surface water toward the eye but no real inward radial flow. Then you wouldn’t see much deep cooling or upwelling. Does that seem right?
To quote the famous Vulcan Dr Spock: “Fascinating”
Talking of cooling ocean temps:
http://www.nature.com/news/2010/100922/full/467381a.html
In a related manner:
http://www.bbc.co.uk/news/science-environment-11391238
The surfaces of the oceans went through a short period of rapid temperature change 40 years ago, scientists have found – but the cause is unknown.
However, events called Great Salinity Anomalies have been recorded in the last few decades in the North Atlantic Ocean – including one around 1970.
The causes of the Great Salinity Anomalies (GSAs) are not clear; and they may not all have the same cause, or progress in the same pattern.
In the 1970s event, fresh water appears to have entered the North Atlantic and lowered the salinity of water in the region.
In large enough quantities, this freshening can slow the Atlantic portion of the global pattern of currents known as the thermohaline circulation – in popular parlance, “turning off the Gulf Stream”, as in the movie The Day After Tomorrow.
Around 1916, when National Geographic was a society publication, had a good article on Hurricane structure and patterns.
Beautiful. That storm must have moved a lot of calories upward.
Why does this post not mention wind-driven upwelling of cold water as Spector and other have suggested? This is the dominant process in cooling the surface water, much of this cooling happens after the storm has passed, so cannot be lost to space:
Cione, J. J., and E. W. Uhlhorn, 2003: Sea Surface Temperature Variability in Hurricanes: Implications with Respect to Intensity Change. Monthly Weather Review, 131, 1783-1796.
http://journals.ametsoc.org/doi/pdf/10.1175//2562.1
Mixing warm surface water to greater depths could lead to greater warming.
Alexey V. Fedorov, Christopher M. Brierley, Kerry Emanuel. (2010) Tropical cyclones and permanent El Niño in the early Pliocene epoch. Nature 463:7284, 1066-1070
Isn’t the evil CO2 supposed to stop all that heat escaping the atmosphere???
It’s really not important how the local ocean circulation changes during a major storm and how the energy disperses in the ocean after a storm passes (though it would be interesting to understand in detail). What IS important to the Earth’s energy balance, i.e. climate regulation (“disruption”?), is; how much energy is transported from the the ocean to the upper atmosphere and out into space by major storms like Igor? What percentage of the total energy influx does it represent over time? (Knowing the total volume of rainfall/storm would allow one to quickly estimate the total energy on the back of an envelope)
Same w/ W. Eschenbach’s insight that daily tropical thunderstorms may remove a significant fraction of the energy influx back into space, thus helping to keep the whole system in balance (negative feedback).
Questions on the flow of water due to the storm ‘surge’ lifting the water level in the center do not add into the thought experiment the speed and size of the storms. Most of these hurricanes are moving at ~ 10kts with an eyewall of ~40 miles radius. The amount of energy required to move the water within the eyewall alone must be immense. It is unlikely that there would be enough to form a torus outside that eyewall that will move and follow the storm.
It would be interesting to see if any research has been done on the fluid dynamics of the ocean under a hurricane. This might provide some better steering input into the models by identifying the amount of energy available to the storm from the ocean especially when the storm is brushing close to land or shallower water. It may explain the ‘jinking’ seen with storms when they approach a coast line.
It will be interesting to see how this transportation of heat out of the tropics affects arctic ice coverage over the next two or three years. The Atlantic had many hurricanes in 2004 & 2005. Perhaps there is a correlation with a 2-3 year lag.
Rattus Norvegicus says:
September 24, 2010 at 10:06 pm
And this is supposed to be a surprise? It’s what hurricanes do.
Rat, you must be new around here. This topic was covered in another article over a year ago.
http://wattsupwiththat.com/2009/08/27/atlantic-tropical-update-ts-danny-looks-to-follow-in-bills-footsteps/
Surprise? – Not hardly.
Heat pump cooling by convection cells was Willis Eschenbach’s baby. Seeing it reminds me that Willis hasn’t contributed anything for a while. I hope everything is okay with him.