Monday, April 18, 2011

The Zonal Potential Temperature plot above is from this Atmospheric Physics PDF. If you read it you will see there is a lot of stuff about atmospheric physics to learn. The big thing I want to look at on the plot is in the northern hemisphere, that up bump.

When I posted my crappy drawing, it was not to scale. The reason simple two dimensional radiation models are so popular is that they assume that the arc of the Earth at any point is pretty much flat with respect to any single point above the Earth. So my CO2 molecule would look more like a BB in a parking lot than a sphere above a sphere. The atmosphere ain't that simple though. Looking at the potential temperature plot, there is a big hump in the tropics and a smaller hump near the north pole. Think of them as high chairs for the CO2 molecule. The is a lot better view from the high chair which is more radiation window for the infrared heat to see.

These high chairs are also not fixed. The atmosphere is like a 60's lava lamp with stuff moving up and down in a somewhat random pattern. Each one of the up bubbles can dump tons of heat to the tropopause and there to space with the bigger picture window.

There are a lot more of these up bubbles in the northern hemisphere because of the land mass to sea surface ratio. As surface warming by either natural or Greenhouse gas forcing occur, the size and frequency of the up bubbles will increase. With in increase in water vapor due to warming, much more heat will be transported up. So this is a major part of the Earth's temperature control system.

Cloud cover increases are one of the big questions in climate change, will cloud cover increase? Of course it will, where it will is the bigger question in my mind. It is pretty obvious that it will increase at certain time of the year in the northern hemisphere. Should it increase near the tropics, it can completely wipe out the impact of greenhouse gas forcing. That is a bit unlikely. There will be negative forcing from increased cloud cover, but it is unlikely to be greater than 25% of the radiative forcing of greenhouse gas increase. Still, 25% is much greater than the less than 10% considered as natural unforced variation in the climate models. This will tend to greatly limit the positive water vapor feed back assumed by many climate scientists.

It kinda sorta brings Arrhenius' second estimate of 1.6 (2.1 with water vapor) degree C for a doubling back into the picture. That 1.6 estimated by Arrhenius has be reduced by most modern estimates to the 1 to 1.2 degree C range. Now all I have to do is prove it! Fat chance right?

The bugger is that data for the troposphere, especially in the Arctic, is pretty sparse and not very long time wise. There is a larger gap in the North Pole satellite data because of the orbits, so a good deal of what is happening in the far North is a mystery. Though there are more Arctic Tropopause maps available thanks to guys looking into the Wild and whacky Tropopause.

So while it will take me probably forever to even figure out how to solve this puzzle, I will keep playing with it. I will probably come back to this post to add some pretty pictures and hopefully an animation of the Tropopause Lava Lamp.

No comments:

Blog Archive