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Wednesday, November 9, 2011

Astromomy and Perspective

Speaking with my significant other, who by the way wonders why scientists think one way while the climate is acting another, prompted me to write this post.

Astronomers view distant stars and planets from a perspective where all they have to work with are changes in radiant energies to figure out why things on that distant object are the way they are. They then relate those observations to our planet and others using the same perspective, radiant energy or electromagnetic, magnetic and gravitation forces, to learn more about the universe.

Much like the weather conditions at the airport, that perspective doesn't provide much information to the people living on the surface of our planet. We have a surface frame of reference. Our perspective does not jive with science.

Choice of frame of reference is an important consideration in studying our planet, not just for communicating with Joe Six Packs that fund research, but to understand the differences between reality and observations through a telescope.

Thermal boundaries are the key to understanding what can be understood about climate. The ocean/atmosphere boundary is a starting point. That is a thin boundary that can release thermal energy much more rapidly that it can absorb. Radiantly, that is not even a consideration, electromagnetic energy is absorbed or reflected, done deal. Conduction, convection, latent heat, kinetic and potential energies are not negligible though.

About 10 meters below that boundary layer is another, with a different time constant or rate of absorption and release of heat energy based on different properties of the molecules and energies in that layer. 90 meters below that is another boundary layer with different properties and time constants. About 1800 meters below that is another boundary layer with another set of conditions that require another time constant. Above the surface air boundary is another layer with different properties and time constants. Above that are other layers or thermal boundaries. Horizontally there are changing pseudo-boundaries all with different time constants and properties. A fraction of these complex boundary conditions are obvious through a telescope and interpretation of the boundary interactions would easily depend on the choice of the frame of reference or the direction of the energy transfer with respect to the observation point. That is basis of thermodynamics, relativity, all science really, motion relative to perspective.

At some point, it should be obvious that the telescopic perspective may fail to explain reality. For surface dwellers, our reality of concern is what happens starting at the surface then further away if that seems to be of importance.

The true reality will be the same in all perspectives. If one interpretation does not match reality, the one not from the surface perspective is an oddity of little consequence to Joe Six Pack. Time to look out the window instead of through the telescope.

Update: While that satisfied the significant other, I thought I would expand for anyone that may drop by.

If you are looking at the Earth from say Jupiter, you could figure out that the Earth had an emissivity of 0.61, or only 61% of the energy it should be emitting from the surface is seen coming out of the top of the atmosphere. The surface at 288 degrees K is emitting 390Wm-2, 61% of that is 238Wm-2. That is the whole deal,
the surface is emitting 390 Watts per meter square of energy, but only 238 Wm-2 is getting out from the surface. The rest is scattered or reflected short wave energy, not infrared.

So from Jupiter you see something change then the surface is 1 degree K warmer, but 238 Wm-2 is still coming out. Well, you think that since the surface is now warmer it has to be emitting 5.67e-8*(289)^4 Wm-2 or 395.5Wm-2 to be one degree warmer, so it should be emitting more than 238Wm-2 at the top of the atmosphere. It is not though it is emitting 238Wm-2, so you can say that the emissivity changed to 238/395.5 or 0.602 instead of 0.61. Problem solved so you go have lunch at the alien pub and plan to mess with Mercury in the morning.

Now, if you happen to be on Mars, you might see the same thing on Earth and say, hum, it looks like 3.7Wm-2 of forcing has been added to that planet's atmosphere. It used to have a surface temperature of 288K with 390Wm-2 and an emissivity of 0.61 so it only emitted 238 at the top of the atmosphere. Here's is what must be happening on the surface. 3.7Wm-2 worth of resistance was added, that is going to cause 5.5 more Wm-2 to be emitted by the surface which will cause the 3.7Wm-2 to restrict more energy which will cause the surface to emit more energy.

Martians are complicated as Venusians know. So you use a power series with the 0.61 emissivity 3.7/(1-.61)=9.5 Wm-2 more should be emitted from the surface totaling 399.5Wm-2 which means the surface temperature is now 289.7 degrees K or it increased by 1.7 degrees due to the 3.7Wm-2 added resistance that got stuck in the atmosphere some where. Now the complex Martians can catch dinner and a movie while planning on studying Mercury the next morning.

Earthings are that complicated or bright. They dumped a bunch of junk in the air an realized it was getting a little warmer. They hire a bunch of Venusians to measure the average temperature and find that it is 0.8 degrees warmer than it used to be. Not being sure if that is a good thing or not they hire a guy with a balloon to measure the temperature as high in the air as he can go.

The Balloon guy has done this before when the silly Earthing thought that it was getting cold, you he did his job and gave the Earthlings the average temperature at 4000 meters. He also gave them a copy of the numbers he had before at 4000 meters.

The old temperature at 4000 meters was 249 degrees K and the new temperature is 250.2 degrees K. The Earthlings stiff the balloon guy because he never got a better balloon and should have gone higher than 4000 meters.

Short on cash, the Earthlings decide to make do with what they have and figured that if it warms by 0.8 on the surface it has warmed by 1.2 at 4000 meters. Scratching their heads they wander back to the Venusians to ask what the heck is going on.

The Venusian explain that the junk that had been dumped in the air restricted heat flow from the surface like a blanket keeps heat from flowing from your body while you sleep. Just like a blanket, that not only restricts flow out but would restrict flow in. Since the flow from the surface is now 394.4 Wm-2 and the flow at 4000 meters is now 222.2 Wm-2, both increased. The surface by 4.4Wm-2 and 4000 meters by 4.24 Wm-2 which means the resistance now is 4.24/4.4 or 0.963.

The Earthlings ask how can that be? It is all because of that water vapor you have which is why we came here. It is good for the complexion.

Isn't it more complicated that that? the Earthlings ask. Well, it can be if you hire a Martian, the Venusians respond. Maybe this is better, the temperature difference was 288-249 or 39 degrees with a Flux difference of 390-218 or 172. You can divide those, 39/172 = 0.226 for the old R value. Now it is (289-250.2)/(394.4-222.2)=38.8/172.2 which is your new R value of 0.225, it doesn't take much change to warm things up a bit.

The Earthlings walk away shaking theirs heads. They know they need to hire a Martian.

Since the Earthlings had bankrupted their entire balloon force, which couldn't make it to Mars anyway, they manage to get a Martian on the radio and explain the situation. The Martian mentioned that Venusians are known to lie and that the surface temperature had to be warmer than that because there was 3.7 Wm-2 restriction in the atmosphere somewhere that their most brilliant mathematicians had determine using complex series analysis which requires the temperature to be at least 289.7 degrees K and likely higher with water vapor.

The Earthlings, just a bit perturbed, confronted the Venusians with the news that they can't measure temperature worth a dare, it had to be warmer because the Martians said so.

Did they give you the water vapor bit? The Venusians asked bathing in their new sauna.

Yes they did! Growled one of the Earthlings.

Laughing, the Venusians tell the Earthing that water vapor would warm the surface more if the restriction was below the clouds or if the clouds were not as abundant. You see, the restriction is just that junk you all have been dumping in the air and it restricts more above the clouds than below the clouds. Since it is above, it warms the tops of the clouds which causes the surface warming to be less than Martians would expect.

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