Friday, April 22, 2011

That Simple Greenhouse Effect

While playing with Openoffice to try and figure out to create charts that have years instead of some garbage on the X-axis, I wandered across a funny post at Gavin Schmit, wrote a post explaining why the Stratosphere cools and the Troposphere warms due to extra greenhouse gases. If you check out the link you will see that Gavin had a face plant moment. After a couple updates, he linked to a newer post called the Sky is Falling.

Trying to make the complicated as simple as possible, is the trick for climate scientists. It falls back to the first thing I was taught in Thermodynamics, Keep It Simple Stupid (KISS). The radiation balance with increased greenhouse gases is not all that simple, but can be communicated a little simpler.

Unfortunately, one of the more complicated parts is the first thing that needs to be explained, that is the Radiation Windows. As I have been on about in the Whacky Tropopause posts, heat or temperature flow from warmer to cooler. That is the first law of thermodynamics and it is a LAW. It is not like a recommendation, that's the way it is. Radiation has its own set of laws. When it transfer heat energy, it will follow the first law of thermodynamics. Every element in the known universe has a spectral signature, that means the radiation it emits is based on the elements that it is made of. Before space probes, astronomers could tell what a star or any other astronomical body is made of if it gave off enough radiation as heat, light or X-ray for them to "see". Science started to become aware of the "hidden" things over the past couple hundred years. Infrared radiation is one of those things.

The photo is from Wikipedia in the article Absorption Spectroscopy. As you can hopefully see, our sun has a very broad electromagnetic spectrum. Each wavelength has different properties and as you can see there are a few black lines which are gaps are missing wavelengths due to the chemical makeup of the Sun. That is our Sun's spectral signature. Other stars will have different signatures unless they have the same chemical makeup, pressure and temperature. The electromagnetic energy of the Sun powers our climate and the different wavelengths responds in different ways to different elements at different pressures and/or phases like solid liquid or gas.

For the greenhouse effect, we are mainly concerned with the atmospheric gases. Not just the greenhouse gases, all the gases. Nitrogen and oxygen are not greenhouse gases, but they still have an absorption spectrum, which means they have an emission spectrum. Anything with heat will emit radiation. The greenhouse effect involves special gases that tend to block outgoing infrared electromagnetic radiation. That radiation can still be transferred to non-greenhouse gases by other means besides direct radiative transfer. In other words, they can be bumped into. If the greenhouse gases could not transfer heat to the other gases in the atmosphere, we wouldn't be here, the world would be about 30 degrees colder.

Barrett Bellamy Climate has this above chart on their website which I am borrowing. You should pay them a visit. The Sun energy in red show gaps that are the same as the black lines in the other picture. Infrared radiation leaving the Earth is in blue and below in gray you can see the spectra of common greenhouse gases. Unfortunately, Nitrogen which makes up most of our atmosphere, is not shown. I will try to dig up the nitrogen spectrum later.

Any infrared radiation leaving Earth's surface or atmosphere has a radiation window if there is no gas absorption spectrum blocking its path. So at different altitudes and temperatures there are different windows. Water vapor, the main greenhouse gas, reduces with altitude to the point it is nearly gone by the top of the troposphere. There are traces above that have an impact, but the main impact is in the lower troposphere with a different kinda impact above the top of the troposphere. Because the other greenhouse gases are over whelmed by the impact of water vapor in a great deal of the lower atmosphere, the CO2, methane etc. gases play their role in the drier air, deserts,poles and upper atmosphere.

Pressure, which reduces with altitude, plays and important role in the physics of the Greenhouse effect. In my best Rod Sterling voice, "Imagine if you will, the rarefied air of the upper atmosphere, at to point where molecular collisions are reduced allowing infrared radiation to become the major component of heat transfer." Up here things get interesting.

As in earlier posts, I call this the Tropopause Sink, because infrared radiation has a picture window up here. Because of the little water vapor and few molecules, the height of the spectra of some of the greenhouse gases is not as tall. They still absorb in their spectra, but fewer molecules will absorb less infrared. More CO2 and more other greenhouse gases will absorb more, but how much more? The principal behind Stratospheric cooling is that CO2 will block more infrared in the spectrum that O2 and Ozone absorb, reducing the temperature of the ozone layer in the Stratosphere. Ozone is of course the main infrared absorber, but ozone is created by Ultra Violet (UV) breaking up O2 so that O3, Ozone, is formed. Things are happening in both directions in the stratosphere. Since the Stratosphere is warmer than the top of the Troposphere, it can heat the top of the Troposphere. This is a bit of a conundrum, if the Stratosphere cools, that is less it can heat the Troposphere, either directly or through a cascade of radiative transfer to Greenhouse gases.

Comparing the Stratosphere temperatures to the middle Troposphere temperatures collected by satellites, you can see that conundrum messing with the principals. According to the Global Warming crowd, greenhouse gases took over in 1950 and have been doing most of the warming every since. If that were the case, I would expect a rises in the Troposphere to correspond with a drop in the Stratosphere temperatures. Since the Satellite temperatures were measured starting in 1979, only the last decade has shown that relationship.

The delay in the inverse relationship of the Troposphere and the Stratosphere can be interpreted a couple of ways. First, that the measurements aren't all that great or second, the CO2 forcing is not as great as thought. While I am far from certain, I tend to go with the second, because the CO2 forcing estimate is a compromise, not a calculation. The first choice still has its place, and a combination of the two is quite possible. Either way, things are not going according to plan in the upper troposphere. Hence, my Tropospheric Sink theory.

Upper tropospheric warming by either Stratospheric radiation or CO2 interaction has plenty of window to get the hell out of Dodge. If the simple models underestimate the heat transfer to other atmospheric gases that can radiate infrared in other than the Greenhouse gas or O2/O3 spectrum, that would explain most of the "Failure to Indicate" anthropogenic warming. As I said, this does not mean there will be no warming, just less, with the potential of increased convection (thunder storms and tropical cyclones) modulating the impact. I need to figure out the Openoffice plotting thing better, then I can post the chart showing the unusual relationship between Tropo and Strato. I am not going into what happens in the upper atmosphere until I fine tune the Whacky Tropopause data.

Middle Troposphere (red) versus Stratosphere (blue), for tropics in anomalies by month starting 01/79 ending 12/10

Okay, I am still dealing with charting issues with Openoffice (I miss my Lotus 123 I used for years). I did figure out how to export the chart as a jpeg. The labeling of the X-axis is still an issue. The chart above is labeled as months instead of years starting in 1979. As you can see the correlation is not super, but you can see the inverse relationship a little in the later months. There is an odd direct relationship in the months corresponding with 1998.

In this chart of potential temperatures, the tropics are the center hump. Again you can see the northern hemisphere smaller hump and the southern hemisphere playing more nicely. I am going to do a north pole and south pole comparison like above. The polar coverage is not equal, so I may have to fiddle with those a bit. The north pole should show more of the poor correlation between Strat and Trop but the southern pole may have better inverse correlation though without much amplitude.

Well, I am making some progress with Openoffice, at least I have the year on the axis. The chart above is for the North Pole middle troposphere versus the upper including the Stratosphere. Not much inverse correlation and lots of noise with a warming trend in the mid Trop and slight cooling in the upper trop/lower strat. The trends at the
South pole were very small with not much correlation.

Update: Sorry about that, the HTML went whacky on me. Now the photos and text should be in order. Since I was fixing thing, You have to go read Micheal Tobias whipping out the F-word.

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