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).

Friday, January 12, 2018

Water resources in Ancient China, part 2: Hot springs in Xi'an

In Xi'an over New Years. Xi'an was a former capital of China during several dynasties, particularly the Tang Dynasty, at which time it was known as Chang'an. There is a reconstruction of what the city looked like during the peak of the Tang Dynasty, when it was the most populous city in the world.

Water, was of course, of paramount importance, and I seem to recall that the capital had to be moved numerous times because of drought. Building canals was one of the solutions over the past millenia.

Xi'an (then Chang'an) had something that other potential capitals, such as Luoyang and Xuchang lacked--natural hot springs. What could be better in a cold climate (especially in winter) than an apparently inexhaustible supply of hot (43C) water? The Tang emperors knew a good thing when they saw it, and built a palace (the Huaqing Palace) on the site.

The palace complex is quite considerable, and includes a number of temples. It had been built on the site of earlier palaces as well, all of which took advantage of the hot springs.

The Emperor in question, Xuanzong, was renowned as a musician (and, according to the tour guide, was regarded as the most romantic emperor in history).

Being musically minded, it seems natural he would fall for a dancer.

The story follows that this same emperor really knew a good thing when he saw it, as he next built a special pool for the dancer--his favourite concubine. So the guide asks, "Do you know what made her so beautiful? It was because she was fat." This makes sense. Fat people are well-fed, and well-fed people are more likely to have healthy children.

Hot water bubbles up from the earth, emerging at the foot of Li Shan, and is conveyed by a series of pipes to a number of pools. Note the hot water emerging from the dragon's mouth in the above picture.

The imperial bath is octagonal, symbolizing the eight directions. The upper shape is that of a lotus, which is the symbol of purity.

Part of the imperial changing room

Yang Guifei's (the concubine) pool. The hole in the centre was not a drain--at one time there was a pipe there and the artesian pressure was high enough for a shower. Now that was luxury.

So after all this build-up about how fat the concubine was, we arrive at her statue.

Perhaps I am a bit jaded, but she doesn't seem fat to me at all. And I know fat--I'm from North America. Maybe she's fat by Chinese standards.

Modern Chinese woman in Shanghai.

And as for the "most romantic emperor" in Chinese history? Eventually, there was a rebellion, which he was too busy enjoying himself in the pool with his beloved to pay much attention to. They had to flee for their lives, and his soldiers blamed the young lady for the troubles of the state, telling him that they would not defend him anymore unless he disposed of her. And what does a romantic emperor do? Off with her head! In the struggle between love and power, there can only be one winner. It's a disappointing ending, but not as disappointing as it must have been for the young lady.

Thursday, December 21, 2017

Ghost malls for ghost cities

Construction is proceeding on large apartment blocks all over Zhengzhou.

Here is a brand new mall that opened a few months ago in the airport city region of Zhengzhou, a few km away from the development featured a couple of months ago.

They call it Joy City. But maybe another name would be more appropriate.

Only a small portion of the mall is active, on the main floor. The upper levels seem to be empty, as are most of the outlying areas in the mall, which I called the 'sacrifice zone'. Within the inhabited zone, there are several high-end jewellery places and a snack shop.

The suicide net here may be for the anchor tenant, whoever that is.

You are probably thinking that the entire mall is closed. No, it has been open for awhile. It's just that the level of occupancy is pretty low.

Happier days

Transformers out back, along with dancing realtors

And it isn't that the entire neighbourhood is empty. Next door was a strip mall that had a lot more customers. But then, it was a real place. Also, just down the street was an older, quite busy neighbourhood. So there are people around. But maybe not enough of them.

Tuesday, October 31, 2017

Huge development in Zhengzhou

The second subway line for Zhengzhou, running from the north end of the city to the airport was completed last year. I took it out to airport city a couple of weeks ago.

Along the way, there is an enormous new real estate development--it must have run about 2 km along the track, almost entirely filling in what used to be a forested area between Zhengzhou and what used to be a separate town (Hua'nancheng). Unfortunately, the subway is enclosed in tube with these horizontal lines, obscuring the imagery.

And here's some video to give you a sense of scale.

Monday, October 30, 2017

Loess in west Zhengzhou

I decided to go somewhere a little different in the city, so on Golden Week, I took the subway out to the civic centre.

Correction: I took the subway to the station that was called Civic Centre. It seemed reasonable at the time to assume the civic centre was there. Since it was a national holiday, I thought it possible that there would be some kind of public event in the space.

The subway system was built very rapidly over the past few years, and is in the midst of an enormous expansion. The subway appears to be built to support the growth model designed by the local urban planners, so that there are portions of it built through areas that are as yet undeveloped.

Such as the 'Civic Centre' station.

Inside the station was a map of the surrounding area. There were three exits, and the third exit appeared (from the map) to be near an amphitheatre, with a winding path through a forest leading to the main road. This was the exit I chose. But when I reached the surface, all that was there was a chewed up field, with a couple of collapsing buildings with a farming family squatting inside. Nearby, a dirt track led to a dilapidated village.

In the distance were several high-rise apartments under construction. So my conclusion is that this area will host the civic centre one day. But not quite yet.
- - - - - - - - - - - - - - - -
South and a little east of the civic centre is a broad ravine with steep sides. Near the subway line there is no easy access, but as one approaches Zhongyuan Road, the ravine becomes a park, and there are a number of easy access points. This park is called Xiliuhugongyuan, or West Six Lake Park (it isn't clear to me if this means there are six lakes, or it refers to lake number six).


Zhongyuan Bridge crossing the ravine

Given the density of population and commerce, Zhongyuan Rd. looks like a better choice for the subway than where it actually is. But then it would have to cross this bridge, which isn't strong enough.

What struck me is the thick accumulations of loess that are exposed at the sides of the park.

The cliffs range from about 5-10 m high, and consist of nearly vertical, fractured faces of silt. Presumably, they resulted from fracturing and successive block failures from the loess faces

When the loess faces collapse, they break into blocks, which themselves 
may further break down over time.

Henan province mainly lies within the great loess plain of China, where loess covers over 630 000 sq km of central China. Loess is composed of windblown silt particles in central China, but is coarser in the west, where it consists of windblown sand. In places along Huang He, the loess terraces rise above the river terrace level by up to 100 m. So the terraces in western Zhengzhou are not spectacular, but they are the only place within the city where I have seen them.


Fractures in the unconsolidated loess in Xiliuhugongyuan. 

Loess tends to be occur in dry climates, as moisture encourages plant growth which will bind the sediment together and prevent it from being transported by wind. Central China is fairly dry most of the year, with annual evaporation exceeding precipitation (Derbyshire, 1998). The majority of rain falls from July to September (it lasted well into October this year), and up to 40% of annual rainfall can happen in one day (which I can attest to, having experienced such days twice).