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Thursday, March 7, 2013

WUWT HotWhoppers of the Day

MobyT | 2:20 PM Go to the first of 10 comments. Add a comment

How does this work?  From WUWT today (parents, be reassured, that geography teacher turned denier no longer teaches geography or anything else):

There is also the transfer of heat from the relatively warmer water through the ice to heat the cold air.

And what do you think phlogiston means by this?
Some have argued for atmospheric heat energy to be used as a better and more meaningful metric than a supposed global mean temperature. Heat is a product of temp and water content. Viewed this way, decreasing water vapour could mean that increasing temperatures have not reflected increasing heat.

Update 1:

Another new factoid, which "simple physics" probably also goes a long way to explaining why an extra cold winter follows an extra hot summer - not! (courtesy John Kehr's guest post):
In January the anomaly in the Arctic was well above average. By simple physics that meant the Arctic was losing energy to space at a much higher rate than average. Normally the Arctic is losing energy at a rate of 163 W/m^2. In January of 2013 it was losing energy at a rate of 173 W/m^2. That 6% increase in rate of energy loss meant that the Arctic ended up with a negative anomaly in February.

Update 2: Fake WUWT skeptics and those darned confusing anomalies (a thermometer is not a human contrivance):

Theo Goodwin says:
March 6, 2013 at 8:58 pm Yep, use of anomalies causes confusion. That is reason enough to get rid of them. But there is another important reason. Use of anomalies hides the actual data – thermometer readings. Taking a thermometer reading is an act of reaching into the environment and withdrawing a fact from it. To convert a thermometer reading to an anomaly you have to compare the thermometer reading to an average reading – you have to hide the fact behind a human contrivance. So much for empirical science.

Update 3: Sure to boggle even the WUWT mind.

How earth heating up means earth is getting colder as explained by dp:
If you are an alarmist you should be happy to know that warm air is a good thing because that heat heads to space. Double good if that heat has come from the ocean. negative balance of energy. Yet we can expect endless complaints of a warming planet. N0 – that is a cooling planet! Hot air – radiant energy to space.

10 comments :

  1. It means he doesn't believe the zeroth law of thermodynamics.

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  2. Zeroth law of thermodynamics - Hmolpedia
    http://www.eoht.info/page/Zeroth+law+of+thermodynamics

    YouTube
    http://www.youtube.com/watch?v=GKqG6n6nAmg

    ReplyDelete
  3. Hmmm, let's see, air temperature above the ice at -20C, water temperature below the ice at -3C, temperature gradient is...?

    Yes, you guessed it, heat flows from the water, through the ice, to the air. Knucklehead.

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    Replies
    1. Let me guess - the ice magically gets hotter without melting warms the air? And the ice magically loses albedo.

      Is that what you mean?

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    2. *sigh* No. Really, weren't you paying attention when you took "Physics for Poets"? On a handy piece of paper, draw two vertical lines, 4" long and 2" apart. At the left hand line, draw a horizontal line 1/2" down from the top extending some distance to the left. At the right hand line, draw a horizontal line 1/2" UP from the BOTTOM extending some distance to the right. Draw a line from the intersection of the lines on the left to the intersection of the lines on the right. It should slope down and to the right.

      The area on the left represents the water uniformly at -3C and the area on the right represents the air uniformly at -20C, the height of the horizontal lines is the relative temperature difference between the two. The area between the two VERTICAL lines represents the insulating ice, and the sloped line is the TEMPERATURE GRADIENT between the water and air.

      The first thing we observe is that this is NOT a Zeroth Law case. The Zeroth Law is invoked when two disconnectd bodies are each in thermal equilibrium with a third, and thus with each other. Equalibrium between two objects is obtained when there is no driving force moving heat from one to the other. In this case, the two objects are said to be at the same temperature. Inversely, if they are NOT at the same temperature, they are NOT in thermal equalibrium. The ice is not in thermal equalibrium with either the water OR the air.

      So rab (Tweedledum) and Peter (Tweedledumber) get a "zeroth" for this exam.

      In this somewhat idealized example, an infinetesmal layer of water adjacent to the ice gives up heat to the infinetesmal layer of ice, said heat flowing "down" the temperature gradient via conduction and finally to the air, via conduction, convection and radiation. When the water has lost enough heat, it changes state and the heat of fusion flows "down" to the air.

      Ohhhh, WAIT a MINUTE you say, the ice just MELTS! In this case, no. This is not a giant well-mixed high ball glass where the ENTIRE MIXTURE of ice and water is exposed to room temperature air. Each adjacent infinitesmal layer of ice to the right is colder than the one on the left, and heat continues on it's merry way. And ice forms and builds at the interface between the ice and water.

      Suppose we get a pulse, or even sustained flow of much warmer water just under the ice? Now, the ice will melt from underneath, until the water cools to the point where it again starts to freeze, but to describe what happens then you need to know the thickness of ice, the mass of warmer water, and it's velocity 'cause now you have dueling heat transport mechanisms. During the summer, melting usually wins and during the winter, ice prevails (for the Arctic, of course). But even during all this, heat STILL FLOWS from the warmer water, through the ice, to the colder air. IF the air gets warmer than the temperature of the water, then the transport of heat is reversed.

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    3. Yes, you're right about that. And as the Arctic ice gets thinner and more particularly when it breaks up, the exchange of heat from ocean to air is much greater.

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  4. What phlogiston means is that he understands the concept of enthalpy, which you clearly do not. For two identical volumes of air, the one with the higher relative humidity has a higher "heat content". You have to add or remove more heat per unit volume to raise or lower the temperature of the "wetter" air, because the water in the air has a higher heat capacity. Heat capacity is a measure of how easily something can be heated or cooled. High heat capacity, harder to heat. Low heat capacity, easier to heat. Look up "psychrometrics" at Wikipedia.

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    Replies
    1. "increasing temperatures have not reflected increasing heat"

      Ah ...so in WUWT-land enthalpy means that as it gets hotter it doesn't get hotter. I see....

      Delete
    2. Texas A&M joke:

      "How do you define gross ignorance?"

      "144 Aggies in the same room."

      Let's say I have to cool 1,000 lb/hr of air with a relative humidity of 5% from 70F to 60F. I'm not going to condense any of the water. Using Trane Co.'s handy electronic psychrometric chart, I have to remove 533 BTU/hr to get it done.

      Suppose the air starts at 20% relative humidity? Now to reach the SAME 60F, I have to remove 4,120 BTU/hr.

      Now, when we're talking climate models, we don't talk about temperature's per se, we talk about HEAT FLUX. Once that flux (about 1,400 W/m^2 at TOA) is done bouncing around, getting absorbed, reflected, re-radiated and what not, we measure the RESULTING EFFECT as temperature. Either on land, over land, in the sea, over the sea, or what have you.

      If you change the net flux, all things being equal, you expect a change in temperature. If I bump the flux up by, oh, say 3.7 W/m^2 it makes a difference though what I'm heating. If I'm heating air at 60F and looking to reach 70F that flux is going to heat only about 1/8th as much air if the final RH is 20% vs 5%. The ratio of 533 to 4,120. So if all the air in the world was, on average, wetter tomorrow than today, you'd get less of a temperature increase, globally (if such a measure means anything) tomorrow, for a given increase in forcing than you would today. Within reasonable limits, you could maintain the same global temperature with an increase in forcing if you had some natural process injecting additional water vapor into the air.

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    3. Fair enough, I was just being a smarty pants.

      (Thing is, of course, that overall, the water vapour content of air is rising, not falling, as earth heats up.)

      Delete

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