Dust flux, Vostok ice core

Dust flux, Vostok ice core
Two dimensional phase space reconstruction of dust flux from the Vostok core over the period 186-4 ka using the time derivative method. Dust flux on the x-axis, rate of change is on the y-axis. From Gipp (2001).

Wednesday, September 30, 2015

Shang Dynasty ruins at Yin Xu

Anyang was one of the earliest imperial capitals in what is now China. Ruins from the Shang Dynasty are on display at the Yin Xu site.

Water drainage pipes.

Cast of bones in mass grave site.

Fragments of inscribed tortoise shell used in augury.

Inscribed tortoise shells and ox scapula are abundant at this site.

Grave site under glass at Yin Xu. I doubt this is a real grave site as opposed to a reconstruction--but on the other hand, this is China we are talking about.

Other gravesites included chariots, horses, and attendants.

Some of the earliest examples of writing that can be traced to modern Chinese appear on ox scapula and tortoise shells.

Grave goods.

Saturday, September 26, 2015

Arctic sea ice extent 2015

Arctic sea ice still appears to be trending downwards.

This chart is a little different over last year's, as TPTB have re-evaluated some past years' extent of sea ice, and found the previous estimates wanting. Almost every value has declined somewhat. The updated values have been added into the analyses below. I have no comment on the updates or the methodology, which is available here.

The question at issue is whether the change we are observing is a secular trend towards zero (in-line with global warming arguments) or part of a larger cycle, in which sea ice extent may eventually return to the heights of the late 1970s.

Many natural systems (and some unnatural ones) are characterized by multistability, whereby there are more than one equilibrium within a system for a given set of boundary conditions. Multistable systems show long periods of relative stability about an area of phase space, punctuated by brief, rapid shifts to alternative long-term behaviours.

The phase space portrait projected above into two dimensions has been interpreted as representing a system that has "switched" from one metastable mode of operation to another. The existence of different modes of operation is tied to the presence of both negative and positive feedbacks within the system. The interpretation is based on empirical data, not on models.

Unfortunately we don't have enough data to be confident of the interpretation. If we had a longer record, we might be able to infer multistability--but ice extent records prior to the advent of continuous satellite monitoring are difficult to compare with more recent records. Unless some proxy record is discovered, we will just have to wait.

Sunday, September 13, 2015

Zhengdong New District is not a ghost city

Apparently, a couple of years ago, 60 Minutes did a documentary on one of China's largest ghost cities--the new business district in eastern Zhengzhou. So let's go take a look and see how this ghost city is getting along.

I would have written about this before, but I had no idea that there were people who thought this was a ghost city. It's because I go there fairly often, mainly for the restaurants, and also for the art market.

Jade. This one could be yours for the price of a small house. In Toronto.

In the spring there was a significant pottery exhibit in the art market.

Brunch at London Glo, in the new business district.

A bit disappointing I haven't found time for the art gallery yet. Or the opera house. Or the Symphony. All of which look a bit like striped easter eggs.

The area is huge. Except for me, everyone, and I mean everyone, goes around by car.

The Soyoo Joy Club. I had to manoeuver through a parking lot full of high-end cars to take this. I was a bit worried at what might be inside.

Farther east, as I neared the east train station, I began to find skyscrapers that were still under construction.

Glorious skyscrapers, surrounded by merchants trying to eke out a living, selling 75-cent meals. Just like in Blade Runner!

Saturday, September 5, 2015

Evolution of Chinese ideographs

. . . on display at the Museum of Chinese Characters in Anyang.

Main gate at the museum in Anyang

Chinese Character Museum

Support columns are styled after those at the nearby Shang Dynasty site of Yin Xu.

The main  foyer.

Model of an inscribed tortoise shell.

Prior to the invention of paper, writing was either carved into stone, or inscribed on flat "bones", like tortoise shells and ox scapula. These last were also used for divination.

Scapulamancy. Holes are drilled into the scapula, then a heated branch is held nearby, and the resulting cracks are interpreted.

Inscriptions on a (different) scapula.

Different sets of characters have been found in different sites within China; however as peoples migrated, the symbol sets began to lose their distinctiveness.

Symbols are usually somewhat dependent on media-carved symbols in stone tend to be runic, whereas the carved symbols in bone could be a lot more expressive due to the softer material.

An interesting display is the comparison between the 3,000-year-old Shang Dynasty characters and the corresponding modern characters.

Friday, August 28, 2015

Recent behaviour of the Case Shiller index (or where are we now?)

One example of multistability I have used in the past few years is the reconstructed state space portrait of the Case Shiller index.

I have been studying state space of complex systems in the hope to better understand them. My original interest was in natural systems-I have gotten dragged into economic data sets because they are generally better.

Data for the Case Shiller index is found here (click the link labelled "US Home Prices 1890 to present"). The first two plots have been posted before, showing the index plotted against itself with a four-year lag.

The first plot shows the annual index to 2012, along with predictions of where in state space the system would plot in 2015, for declining house prices, constant house prices, or rising house prices (in inflation-adjusted terms). The major features are two very long-term islands of stability, at about the 70 level (from 1915 to 1945) and around the 110 level (until 1999); and the large crashing loop that has been traced out since 1999.

This plot shows the same information, but monthly from 1954. The area of stability occupied until 1999 is circled in yellow, and the large "cycle" is also visible, showing that the system was following the trajectory of rising house prices in 2014.

The last plot represents the most recently available data, projected monthly, but it shows the same thing--the long-term area of stability at lower left, and the big loop, now nearly closed. The last available point is reasonably close to the projected state for 2015 (which itself would be averaged over the year).

Is this a potential area of stability? Sadly, no. In this type of plot, long-term stability will have to occur along the y = x line shown on the second graph in this posting. Presently, we are far below or to the right of this line.

If house prices had been frozen at the levels of the end of 2011, we could have developed a region of stability. But the stable state would have been within the large area of stability that existed prior to 1999. Who the hell wants that (apart from young people hoping to buy a house)? So we are embarking on yet another price increase, once again into a market with no ability to support the higher prices. The long term prognosis is for another rise and collapse. Time will tell how big it gets.