The Atlantic has been running warm lately, but that’s because there’s been little happening with Nature’s natural heat transporters. WUWT commenter SteveM pointed out something interesting in the latest SST image from NESDIS, but before we have a look at the animation I developed from that imagery, I thought we should have a look at the role that hurricanes play as heat engines.
First an animation from Goddard Space Flight Center:
And another, showing how the heat transport and surface cooling process operates.
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.
Now let’s watch this simple animation of the last two weeks of Sea Surface Temperatures and you’ll see the cool water tracks left by hurricanes Daniel and Earl:
You can see the cool tracks in the last frame. Note also the large and growing La Niña off the west coast of South America. It’s turning deep purple and on to black. Way cool.
Could a scientist tell us how an infrared picture of a hurricane is looking taken from space ? The color to my humble belief would identify the heat radiated into space !
Are the hurricanes in reality the airconditioners of planet earth ?
wayne says:
September 8, 2010 at 11:15 am
It rains! Obvious!
Many of the comments here concern the warmth being carried out of the ocean, into the northward spiraling storms, and into the upper atmosphere in the Northern Latitudes. A not insignificant aspect of this process is that the subsolar point (where the vertical ray of the sun hits) is now at the latitude where these storms (mostly) begin. As I write this, it is about 5.5 degrees N. Lat., heading toward the Equator and points south. Thus, the ocean during the peak of the hurricane season is also at the peak of its intense solar radiation. Until early October this won’t change very much.
Follow the declination here:
http://www.jgiesen.de/deceot/
George said:
“As for what all that latent heat does in warming the atmosphere (above the water); it doesn’t do anything. Can’t you understand that that “heat” got used up converting all those megatonnes of sea water to atmospheric water vapor; so there isn’t any left over to heat the lower atmosphere. And that lighter than air water vapor rises up, and forms that big cloud swirling mass; and at that time (that the cloud forms) the latent heat is returned to the upper atmosphere to warm the upper atmosphere which ultimately radiates much of it to space.”
If warmed air is an isotropic radiator, and I have no reason to think it isn’t, why would more than just over half of that radiation find it’s way to space? Obviously at some point all excess heat goes into space, but we’re talking about a much shorter time frame here.
Why does blowing across the top of a hot cup of coffee cool the coffee?
Evaporation. SSTs are high before the wind affects the top 20 meters or so as that is the size of the swells in a cat 3+ hurricane.
Your coffee is only cold on the very top and if you stop blowing on it, it warms back up until the whole cup has cooled.
wayne says:
September 8, 2010 at 11:15 am
It rains! Obvious!
Of course, of couse. The Rain! ☺
I was really meaning if you could look at a small cell map of the AMSU of, let’s say, 150 mb level would you also see a slight warming tracking after the hurricane passes? That energy increase would be totally dwarfed by the loss in ocean water but does that appear also. Just a scientific curiosity. Guess Dr. Spencer would know. Might actually show a cooling also, dunno.
Yes it becomes very indistinct. I experienced a super typhoon on board a U.S. Navy ship in the 1970’s (Typhoon Amy off Guam Mariana Islands 1971) which had winds up in the 140+ (175 mph) knot range for a while.
http://en.wikipedia.org/wiki/1971_Pacific_typhoon_season
I stood a watch in the ships bridge when winds were 120 knots and at that time the sea surface was just a gray haze and looked much like a ground blizzard. You could not see the water at all just the blowing spray off the wave tops. We had a few waves put green water on our open bridge windows 3 levels above the main deck.
After the typhoon I talked to some of the boat sailors (submariners) who also went out of port during that storm, and they told me there was extreme turbulence at over 100 feet depth and they had to go deeper than that to avoid severe pitching and rolling from the wave action above.
In short a hurricane or typhoon causes substantial mixing down to 100- 200 ft depth based on what I was told by the boat sailors.
The huge surface area of all the sea spray plus high winds can transfer a staggering amount of heat energy from the water to the air, in the form of evaporated water, and the cooling effect on the sea water surface is very substantial.
All that water gets lifted to near the stratisphere by the storm where it can radiate heat away to the sky at the cloud tops as even more heat is released as the water vapor freezes out to ice crystals. Then that ice descends and melts to produce a very cold rain as the cycle continues.
Larry
“”” hotrod (Larry L) says:
September 8, 2010 at 12:58 pm
……………………….
After the typhoon I talked to some of the boat sailors (submariners) who also went out of port during that storm, and they told me there was extreme turbulence at over 100 feet depth and they had to go deeper than that to avoid severe pitching and rolling from the wave action above.
In short a hurricane or typhoon causes substantial mixing down to 100- 200 ft depth based on what I was told by the boat sailors. “””
Well I wouldn’t confuse severe turbulence at 100 ft depth with the notion that waters at that depth are being exchanged with surface waters.
Water is not incompressible; no matter what they tell you; so when you have big waves; 50-100 ft or more on top of deep ocean water, the pressure transisents of those waves passing overhead is of course going to create havoc at 1-200 ft below, in that deep water. That doesn’t mean that deep water is going to come up to the top; along with your submariner friends.
I’ve done a whole lot of diving (free diving) in waves that are approaching the break line coming into a beach; so that the wave peak to peak height was of the order of half the average depth; and down at the bottom, you certainly feel the pressure of the wave peak going over the top; but I’ve never been sucked up to the surface; just rocked in and out along the bottom.
If there was large mass transport of deep water to the surface in severe storms it would probably kill much of the sea life being tossed around like that.
Enneagram:
September 8, 2010 at 11:50 am
Darn, sent that last one to myself, should have tagged to you.
“”” Caleb says:
September 8, 2010 at 10:56 am
My own sense is that the cooling left behind a hurricane is less due to upwelling, and more due to the actual removal of heat from the surface waters, than most people suspect.
………………………
But here is where my ideas run into a problem: The satellites I know about don’t look down on a hurricane and see hot things. Instead they see some of the coldest cloud-tops on earth, with temperatures lower than a hundred below zero, (F).
Well Caleb; the problem with using the word “heat” as a noun; instead of a verb; denoting a process, is that our imagination then runs amok; and “heat” becomes “hot” , which is at loggerheads with your sub zero cloud tops.
This image is compounded by the totally fraudulent “laboratory” demonstrations where they take two cylindrs of air; drop a small chunk of dry ince in one, to give it more CO2 ( a very popular “doubling” technique); and then put an incandescent “HEAT” lamp nearby so you can see that the one with the “doubled” CO2 gets HOTTER than the other one.
One problem is that there aren’t a whole lot of INCANDESCENT HEAT LAMPS pointing up in the air; out in the wilds.
The HEAT SOURCE that Mother Gaia uses in HER LABORATORY DEMONSTRATION is like a typical garden brick that has been sitting in the shade and is at a Temperature of 288 Kelvins or +15 deg C. That is the typical source of LWIR radiation that is heating the atmosphere by way of the green house gas capture process.
Well of course we all know there is conduction and convection from the surface going on as well as evaporation; but from the radiation point of view the earth does NOT look like a 2800 Kelvin Incandescent lamp; which probably has its spectral peak at somethign like one Micron rather than 10 microns; and since it is 10 times the Temeprature of a typical garden brick it is radiating 10,000 times the 390 W/m^2 that Trenberth uses for his typical earth surface radiant heater.
Humans DO NOT sense 10.1 micron peak wavelength thermal spectrum radiation as being “HEAT”; in fact we don’t sense it at all as anything. We have to go out of our way with cooled detectors to even detect such radiation at all.
But those “Science guy type” TV frauds lie to us and convince us that their fake experiment is demonstrating the greenhouse effect. It isn’t; it is demonstrating a completely different effect with a completely different spectrum from a completely different artificial soure of radiation that human skin DOES detect as being what WE call HEAT.
Nobody ever suffereed from heat stroke in the middle of a category five Hurricane; it gets bloody cold in one of those things; but it is being fed by thermal energy from the warm surface waters of the ocean under the right atmospheric conditions.
I guess the Censorbot doesn’t understand Australian adjectives; so it is sitting on my last post. In any case here’s the legal disclaimer. In referring to the “fraudulent “Science guy” types” I was simply using that term as a descriptor; and was in no way pointing personally at that chap; whoever he is, that goes by the name of “the science guy” somewhere or other. Dunno where since I have never seen his act.
Cooler Atlantic makes cooler Arctic.
Kewl post
This paper seems to address the wave mixing issue — perhaps some of you might care to comment on its content.
http://www.mmm.ucar.edu/people/sullivan/talks/papers/aha.pdf
Larry
The surface water layer will have significantly reduced density due to the rain. It may be that the surface density is lower than the warmer but saltier water below, thus inhibiting upwelling and mixing of layers and delaying surface water temperature increase.
If I remember correctly, wind acting on the surface of the ocean creates a mean current that is at right angles to the wind (known as Ekman spiral). Consider then, the wind circulation at the surface of a hurricane. It’s a circle and the mean water flow from the circulation is radially outward. Compound this with the fact that this outward flow is downhill due to the low pressure at its center and you get a giant sucking straw at the center of the hurricane that is pulling water up from below, spewing it outward and down.
It seems to me that the total effect is sort of like a moving toroidal pump that is circulating cold water up from below to be replaced with water flowing downwards at the perimeter of the circulation. It also seems that this could be working on far more than near surface water.
I wonder if there isn’t also a nutrient track that would be detectable in the wake due to the nutrient rich deep water being pulled up into the relatively low nutrient upper layer. The nutrient levels might even serve as a proxy that would give you a clue how deep this flow is operating.
Another point to consider in the discussion about where does all the heat energy go is the whole kinetic energy balance. A hurricane is moving a massive volume of water vapor (and other gas) at high speed. Heat energy is not only being radiated it is being converted to kinetic energy.
RE: hotrod (Larry L) Thanks for the first-hand description. In many ways I learn more from eye-witnesses than anyone or anything else.
RE: George E Smith Thanks for responding. Appreciate the fodder for my hungry brain.
“Note also the large and growing La Niña off the west coast of South America. It’s turning deep purple and on to black. Way cool. ”
I’m having a seriously hard time believing the temps off the west coast of Central/South America. There’s not even a single pixel’s difference from black to orange in some spots. Unless there’s some sort of major upwelling current right there that doesn’t mix to any meaningful extent with the waters to the NE I’d have to wonder about the validity of the data.
REPLY: That is generally the major characteristic of a La Nina – Mike
hotrod (Larry L) says:
September 8, 2010 at 3:03 pm
The paper you reference is entirely the product of numerical modeling. As the authors state: “The above predictions need to be validated against observations in high-wind conditions.” While I concur, on the basis of observations, that plunging crests from hurricane-driven waves are effective means of mixing, the depth of that effect is on the order of a few meters. This should not be confused with the depth to which wave-pressure variations are felt, which may extend downward to ~250 feet with typical 10-second waves raised by hurricanes. In deep water, the pressure becomes effectively extinct at half the wavelength, which is given in feet by 5.12T^2, where T is the wave period.
Peter H says:
September 8, 2010 at 4:16 am (Edit)
“Yes, I think it’s reasonable to say they might have cooled the sea surface.
But what about at greater depths?”
Generally speaking, you can expect to see mixing of the water column under a hurricane track that is as least as deep as the maximum wave amplitude generated by the storm. I heard that Earl was generating 48 foot waves, which means that given most of the heat content in the oceans is in the top 15 meters of the water column, that the cooling tracks generated in sea surface temp measurements are pretty homogenous for the water column. On the other hand, mixing can also cause anomalously warm surface waters to be cooled simply by dilution with deeper waters they are mixed with, without transporting most of that heat to the upper atmosphere in the cyclonic system.
Andrew says:
September 8, 2010 at 5:55 pm
Are you single?….If you are not then you have all the data for a total understanding of La Niña (The Girl). 🙂
Your being read and I agree that it’s only the top x meters that gets actually cooled. If there is deeper water slightly warmer than this new cool layer then it will equalize over time.
Mark Cooper says:
September 8, 2010 at 3:14 pm
“The surface water layer will have significantly reduced density due to the rain. It may be that the surface density is lower than the warmer but saltier water below, thus inhibiting upwelling and mixing of layers and delaying surface water temperature increase.”
Guess you think all of that moisture rained by a hurricane is coming strictly from the moist atmosphere and not the ocean below. I view it the other way around and upon evaporation of a huge amount of seawater occurring below a hurricane the ocean salinity is being first increased, rising to heights, and raining down thus nullifying that same opposite effect. Decrease salinity, I can’t see it. It’s easy to just ignore the very opposite side of the action being mentioned.
Hillo, hello, hello?? Do you live near Ottawa? Are you concerned about chemtrails? Can we work together?
Thanks,
Jaydayrock
[Reply: chemtrails discussions not allowed here. ~dbs, mod.]