Heat Rises, Who Knew?

The Gulf Stream in False Colors.  Red up to 25.0 C Blue less than 10.0 C

The Gulf Stream in False Colors. Red up to 25.0 C Blue less than 10.0 C

Original Image

From this posting:

http://cnls.lanl.gov/~petersen/header.html

The posting has a large number of very nice pictures in it. What got my attention was the caption for this image:

Gulf Stream On May 2, 2001, the Moderate-resolution Imaging Spectroradiometer (MODIS) obtained this spectacular image of the Atlantic Ocean’s Gulf Stream. The false colors in the image represent “brightness temperature” observed at the top of the atmosphere. The brightness temperature values represent heat radiation from a combination of the sea surface and overlying moist atmosphere.

The red pixels in this image show the warmer areas (approaching 250C), greens are intermediate values (12-130C), and blues are relatively low values (less than 100C). Notice the considerable detail in the swirls and gyres of the current patterns in the Gulf Stream.

UPDATE: As noted in comments down below, that is in error, the legend in the upper left of the map shows they lost a decimal point. It ought to be 25.0 C not 250 C.

The brightness temperature values represent heat radiation from a combination of the sea surface and overlying moist atmosphere.

Now I’ve been pondering if maybe the satellite temps that record higher in the air are reading a bit high because they are seeing the heat being dumped from the surface (that surface being cooled in the process). So this, too, got my attention.

So there are only 2 reasonable interpretations I can put on this.

1) The caption may simply be very wrong.

2) The image is proof that it’s all about the convective HEAT flow and not at all about the temperatures.

UPDATE: Well, it turns out that “Door Number One” was the right one. They screwed up the caption.

But Wait, There’s More

So I looked a bit further and found this link to what looks like the same image:

http://visibleearth.nasa.gov/view_rec.php?id=1722

And it’s from NASA, so you know it must be right! ;-)

With the text:

On May 2, 2001, the Moderate-resolution Imaging Spectroradiometer (MODIS) obtained this spectacular image of the Atlantic Ocean’s Gulf Stream. The false colors in the image represent “brightness temperature” observed at the top of the atmosphere. The brightness temperature values represent heat radiation from a combination of the sea surface and overlying moist atmosphere.

The red pixels in this image show the warmer areas (approaching 250C), greens are intermediate values (12-130C), and blues are relatively low values (less than 100C). Notice the considerable detail in the swirls and gyres of the current patterns in the Gulf Stream.

Gee, so far it’s the same… wonder if anyone credited someone… or just copied… But hey, they are all government, so I guess copying from each other is OK.

UPDATE: And they even copied the same wrong caption.

Then it goes on:

This image was produced using MODIS’ detectors that are sensitive to the 11-micron wavelength. Brightness temperature is actually a measure of the photons at this wavelength received by the spacecraft, but presented in units of temperature (Celsius). Since the atmospheric water vapor emits photons at this wavelength in addition to those emitted by the underlying sea surface, what you are actually seeing is a combination of both. Thin clouds and water vapor at higher altitudes appear as cooler areas.

So what we are really seeing is an 11-micron emissions map. What that image is showing is that as the water vapor over the “hot part” of the Gulf Stream rises, it emits a boat load of heat energy in the 11 micron band, dumping it’s heat to space (where the satellite can see it).

So here we have a very clear and very direct visualization that a slightly warmed surface causes a very large emission of energy to space. It happens over the warmed area. It happens in very close synchronization in time (or we’d have more smearing between surface and top of the air) and there is so much of it that it can give a ‘brightness temperature’ difference clearly visible at altitude.

As a side note: It also says that once the water condenses to clouds you get a cooler reading. Of course: since by then it’s dumped it’s heat (or it could not have condensed to cloud). But this also means that reading the temperature of a very fast process could give you a very high reading if you catch it as the vapor radiates or a very low reading if you catch it after condensation. To me, this says that looking at temperature can be very misleading as you are not seeing the heat and it’s heat that matters. But they seem to have a bit of clue about that:

Heat is being released into the overlying atmosphere from the ocean, raising the humidity. This image depicts the complex interaction of the sea with the atmosphere.

These images were produced from data collected and processed by the University of Wisconsin-Madison’s MODIS direct broadcast receiving station. The MODIS sensor flies aboard NASA’s Terra spacecraft, launched in December 1999.

So they clearly understand it’s all about heat flow, and that the heat can show up as all sorts of temperatures, and that it’s a very complex “interaction”.

Maybe we can get them to go talk to the “climate scientists” and explain to them why temperatures are a lousy proxy for heat flow…

In Conclusion

I think this one image, with the caption, pretty much says it all about what’s wrong with using temperatures to decide if we are gaining or losing heat. It also gives some pretty good clues about why the satellite temperatures are sometimes divergent from the surface temperatures (as they are measuring different things and with different heat flows, thus different temperatures). Further, it graphically demonstrates the dominance of the hydrological cycle and evapo-transpiration / convection over the radiative heat transfer. The Gulf Stream is clearly warming the atmosphere dramatically, rapidly, and with no attention to CO2 at all.

I think this supports the notion that any added heat trapped by CO2 will simply be convected away at great speed and with little to no temperature rise at the surface. Though given the other errors in the caption, I have to wonder if the “top of the atmosphere” is also correct. But assuming it is, we’re seeing significant heat transfer from ocean to the top of the sky.

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About E.M.Smith

A technical managerial sort interested in things from Stonehenge to computer science. My present "hot buttons' are the mythology of Climate Change and ancient metrology; but things change...
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14 Responses to Heat Rises, Who Knew?

  1. Mike Jonas says:

    Seems it would be worth your while to contact NASA to resolve some of the unknowns.

  2. harrywr2 says:

    LOL

    Some idiot lost the decimal points.

    The scale should be is 0-25C.

  3. E.M.Smith says:

    @harrywr2:

    Given that, I think I’ll need to pull the posting… rewrite the posting.

    UPDATE: I’ve pulled the parts of the posting that talked about the high temperatures and left in the bits that talk about the visualized process. Thanks for the “catch” on the NASA boo-boo. You’d think those guys could keep a decimal point straight (and keep metric and traditional units straight) but I guess not…. Note to Self: Always check caption under picture against caption / key IN picture. Just glad I had Option One in the original posting ;-)

  4. Ian W says:

    I think that the important point that is almost always missed is that the latent heat that is seen by the satellites as it is emitted as the water vapor condenses on _cooling_ and as the water droplets freeze on further _cooling_ is NOT related to the _temperature_ of the atmosphere. The amount of heat is proportional to the amount of water changing state.
    This means that use of Stefan Boltzmann equations based on temperature is not valid; it is not black body radiation it is latent heat of state change.

  5. Laurence M. Sheehan says:

    Heat can be lost without the temperature falling, or gained without the temperature rising when H2O changes state, and the opposite can happen and often does. The terms “warming” and “cooling” are generally related to temperature, and not heat gain or loss.

    In evaporative coolers, the air coming out is much cooler in temperature, and has lots more heat in it than the air going in when the relative humidity is less than 100%, the less the relative humidity, the greater the temperature cooling effect. Not thermodynamics, but chemistry. Bodies of water with air movement over them are essentially evaporative coolers, and the air cools in temperature as well as the water. The body of water gives up heat to the air, as H2O molecules are entrained in the air and change from liquid state to vapor state.

    We engineers who used slide rules and scientific notation a lot rarely misplace decimal points, but younger engineers who have used primarily calculators and digital computers do misplace decimal points far to often, I noticed before I retired.

    Great article, E.M. I lived in Jacksonville, FL for 6 years after I retired. My house there was on ancient beach sand.

  6. Malaga View says:

    I think this supports the notion that any added heat trapped by CO2 will simply be convected away at great speed and with little to no temperature rise at the surface.

    Seems like a very sensible conclusion to me….

    PS: Thanks for tidying up my comment yesterday… and apologies for causing the problems.

  7. Larry Geiger says:

    UHI – Drive towards the city and the temp goes up.

    OHI – Drive towards the ocean and the temp goes up. The ocean moderates the temperature along the coast. That’s why people build condos along the beach. The earth is 75 to 80% land, right? Hee hee. The guys who keeps saying we need to know what the ocean is doing is correct.

  8. Jason Calley says:

    Ian W says: “This means that use of Stefan Boltzmann equations based on temperature is not valid; it is not black body radiation it is latent heat of state change.”

    Yes, and a wonderfully powerful insight! One of the reasons why I love hanging around this site is that hardly a day goes by that I don’t learn something, either from E.M. or from the various comments.

    Of course, even the radiation from the land is not black body radiation, but why should we have to comply with the messy, complicated real world, when the simplified model described by the Stephan-Boltzmann equation is available? After all, we are only arguing about tenths and hundreths of a degree. :)

    By the way, that is a good point that you make, E.M., regarding “It happens in very close synchronization in time (or we’d have more smearing between surface and top of the air)”. The fineness of detail and the sharp demarcations of temperature change also point out the fact that we are looking at convection effects, moreso than radiative effects. If the observed radiation at the top of the atmosphere were due to air warming from sea surface radiation, then we would see smearing commensurate with all sea surface in a direct line of sight from any given location at the top of the atmosphere. In other words, the detail shows not just localized effect in time but in position as well.

  9. E.M.Smith says:

    @Lawrence M. Sheehan:

    So the fact that I started college still using slide rules (and love them and still own a half dozen ;-) is a ‘feature’? I can agree with that.

    I find that I still keep that “shadow estimate” running in my brain as a sanity check on the calculator / computer. The same habit slops over into other analysis as well. Always a shadow evaluator…

    Grew up with a swamp cooler. Learned about heat of vaporization at about 5 years old… still have trouble remembering that some folks don’t know it…

    Interesting point about the sand. Might be worth finding where there are ‘sand deposits’ and their ages. Near Davenport Florida there is a large “sand quarry” at about 120 ft elevation …. Hmm… I feel a whole new line of investigation coming on ;-)

    @Malaga View:

    Wasn’t you who caused anyhing. It’s the way WordPress treats map embeds for “security” reasons. So “no worries”.

    @Jason Calley:

    Glad you liked it. There is a lot you can learn from looking at the actual data, even in picture form, and just asking “What?”. Then “Why?”… Then “what does that imply”…

    Somewhere along the line I learned that ‘order of execution’ matters. First “what’s going on”, then “why is it doing that”, and only THEN “what does that mean” or “what does that imply”. The Warmers have this backwards too. They start with “What does CO2 imply” then work to “how that ought to work” and finally conclude with “what ought to happen”… skipping the messy bit of actually looking at what is happening and asking “Why?”…

    And at it’s core, all I really do is look at what is in front of me and ask, in order: What? Why? Sometimes How? then; What does that imply? Followed by a cross foot cross check against other lines of reasoning. The “sanity and consistency check”.

    One short paragraph. Not even a subroutine sized set of directions. That’s all it takes.

  10. Larry Geiger says:

    “Might be worth finding where there are ‘sand deposits’ and their ages.” Isn’t ‘sand deposit’ the definition of Florida? The Ocala Forest and much of the surrounding area is a large sand dome from which many of the nicest springs in the state originate. There is generally deep sand anywhere Longleaf Pines grow.

  11. E.M.Smith says:

    Sorry, forgot about the Florida context… I was thinking wider than that. It ought to be ‘productive’ to find where there are sand deposits all along the Gulf coast and probably a ways up the eastern seaboard as well… Probably in other countries too….

    But yes, I’ve heard Florida described as a sandbar with beaches and trees sitting on limestone from old reefs.

  12. John F. Hultquist says:

    Note in your image that the heat of the Gulf Stream doesn’t seem to make it very close to NW Europe. As you mention it is rapidly flowing off to space. The warm salty water flowing out of the Mediterranean Sea flows east and north (Coriolis force) and does add warmth to the N. Atlantic (over which the winds blow on their way to Europe), and then the water chills and descends.
    ~~~~~~~~~~~~~~~~

    Sometime ago I responded to a comment and the info here may be of interest to those reading here. There is much on the web about the landforms of the SE coast but as that really isn’t the nature of the post – just these two interesting parts:

    One: the building material – coquina — for the fort built at Castillo de San Marcos on the Atlantic coast of Florida:
    http://florida-vacation-travel.com/castillo-de-san-marcos.html

    and two: the “Trail Ridge” at The Okefenokee Swamp on the Georgia – Florida border. “The swamp was formed over the past 6,500 years by the accumulation of peat in a shallow basin on the edge of an ancient Atlantic coastal terrace, the geological relic of a Pleistocene estuary. The swamp is bordered by Trail Ridge, a strip of elevated land believed to have formed as coastal dunes or an offshore barrier island.” From:
    http://en.wikipedia.org/wiki/Okefenokee_Swamp

  13. Jason Calley says:

    John F. H. says: “The swamp is bordered by Trail Ridge, a strip of elevated land believed to have formed as coastal dunes or an offshore barrier island.”

    The same process was at work further south as well. The St. Johns River runs the length of North Florida parallel to the Atlantic coast. The west bank of the St. Johns marks the old sea coast of Florida, but the ancient offshore sand bars and barrier islands consolidated to create the modern coast.

    One thing I find puzzling about the sand dunes which still border the St. Johns is that some of them are mined for titanium. The titanium ore is composed of individual sand grains mixed with the other normal grains. I remain mystfied about how those titanium ore grains show up in localized dune areas. Where did they come from? How did they get concentrated in specific areas? Who ordered that?!

  14. John F. Hultquist says:

    Jason,

    In spring of 1972 we visited a dredge mining operation that was making islands and lakes as they recovered some of the heavy minerals. We have slides but I can’t remember exactly where it was but it was on the same trip that we last visited the Okefenokee.

    John

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