5. The Fireworks balance sheet: Climate sensitivity of CO2, including clouds

So far we only spoke about the radiation mechanisms.
Of course we need to include clouds, albedo and so on.

In fact, that was what I actually started with, and that is how I found out that I needed a radiation simulation.

I put every significant climate aspect I knew in a spreadsheet, and made an energy balance of it in the way Kiehl/Trenberth did.

I did this by dividing the radiative spectrum in sections with a specific behaviour, and calculated the energy flow for each of them. Combined they seemed to give quite good results.

Once again the basis is very simple and easy to understand, and everybody can vary all parameters to create his own preferred atmosphere.

In this scheme you can see the output of the 25 layer model I experimented a lot with:

The hardest parameters to estimate were the radiative mechanisms that divide the absorbed IR energy in OLR and Ed.      (more…)

6. Convection and the thermohaline circulation

As an “entrée” for the next chapter, I wanted to share some thoughts about oceanic convection.

I got to think about this topic, when discussing atmospheric convection with an oceanographer. It seemed better to talk to him about his field of expertise, so I tried to apply my ideas to the oceans, and the result was enlightening at least.

The basics
I think there are two basic laws of thermal convection:

  1. Convection in a fluid or gas can only occur when there is a heat source that is positioned beneath a heat sink
  2. The convection is restricted to the area between those two points

The picture shows heat sources A and B, and heat sinks C and D.


Basic convection in a fluid

According to the basic laws, the convection will be “trapped” between levels E and F, determined by high heat sink C and low heat source A.

Heat source B will only heat up the water above level F, as heat sink D will only cool it below level E. Both don’t contribute to convection in any way.


7. Convection: the cooling feed back of CO2

After building my simulation and energy balance program, I was quite satisfied that they seemed to describe climate accurately, and showed all relations between the parameters, so I could experiment with them.
Just one question was left to answer: how can we quantify the feedbacks that are active in climate, i.c. those of temperature and CO2 concentration. If these feed backs were quantified, the model would be able to tell a lot more about the climate sensitivity of CO2.

So I tried to understand the drivers of the energy flows in the atmosphere.

The most important one is convection: not only is it the cause of wind, it also determines the height of the tropopause, and the temperatures in the atmosphere through the adiabatic laps rate.
But most of all: it drives latent heat transport, and even amplifies it because of the increased evaporation as a result of wind.

Convection is by far the greatest contributor to the Eu, and thus responsible for most of the cooling of the earth.

So convection is the great driver of climate.
Which leads to the next question:              (more…)