No not that Climatology

Well, back to writing some posts. A fellow I know needed me to help him move some cattle. That meant quite a bit of time in the saddle, and then hauling winter feed to the new location. Oh great I get to ride drag, and no that doesn't mean riding in women's clothes. It's where you get to smell the cow flatulence all day and eat dust for hours on end at the back of the drive.

I have worked with a lot of people over the years in what I call planetary sciences. This also includes atmospheric research. Over the years I have built a number of instruments and conducted experimental studies in support of this type of work so I naturally developed an interest in the subject. One aspect of this field is obviously the climate of earth both in the past and the present. The present day arguments over modern climate change don't hold much interest for me but the past or paleoclimate studies do. 

The first aspect of this is climate change due to the orbital mechanics of Earth. This has been pretty well established and one can read some of the papers I've put in my Google drive if you have an interest. So rather than just copy and paste data and look at it that way I decided to develop my own data set. Which as it turns out requires modelling the motions of the planets with respect to the sun in the solar system.

Since I don't have access anymore to a Cray supercomputer, or a massively parallel cluster  I had to make do with what I had. I followed the work of Laskar and Berger to develop my model but in a much simpler way. I think I have captured the detail I need to but that remains to be seen. The first step is to model the changes in obliquity, precession and eccentricity of the Earth's orbital cycles. My first cut is shown in the graphs below. 

The obliquity of the Earth's axis and the precession seems to be in pretty good agreement with other work but the eccentricity calculations still need some more work. I only modelled the system out to 500,000 years in the past, and have shown here only the last 250,000 years. There are a number of reasons for doing this but the main one is I'm really only interested in the time when modern humans and our most recent predecessors were present.

What I'll be writing about in the future are the climate shifts associated with this and represented by the data set from Antarctic ice core data. The data set I'll be using is shown below. The deuterated water present in the ice is associated with heating and cooling of the planet.