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).

Sunday, November 18, 2012

Another exciting day

Saw something I hadn't seen before (but knew was theoretically possible).

The power went out early this morning. But it wasn't completely out--my computer reported it was still charging, and the lightbulbs in the kitchen were flickering dimly. So I got out the multimeter and measured the  voltage coming out of the wall. It came in at a grand 18 V, less than one-tenth normal. But there were little transient flickers of higher voltage, so I unplugged the computer.

The power came back--sort of. Some things started to run, although the lights seemed unusually bright and the fans were spinning much faster than normal.

When I measured the voltage in one of the kitchen outlets, I measured about 370 V. Again, with transient flickers of much higher voltages. But there were other outlets only producing about 20 V.

Theoretically I knew such a thing was possible. The power coming into the building was three-phase, and many electricians here have hands-on experience without any theoretical knowledge of what they are doing, so after we had the building wired and connected to the grid, the first thing I did was to check the voltage output everywhere possible.

For three-phase power you have a ground and three active terminals. In Ghana, the voltage between the ground and any active terminal is 230-240 V (ideally--although on most days it is considerably less). The voltage across two active terminals will be around 370 V. If the house is wired properly, one-third of the outlets will run off each one of the active terminals and a ground. If the house is wired improperly, it is possible that one-third of the outlets will be run off two active terminals, giving you a voltage at that outlet of 370 V.

In our case I knew the house was wired properly. So the only explanation was that after the first power outage, the electrical workers must have connected their wiring improperly, crossing the ground with an active terminal, blowing up appliances from Bortianor to Kokrobitie.

You'd like to think that electrical utility workers would be better than that. Yes, you'd like to think that.

Tuesday, November 13, 2012

Argentina sues Ghana over the Libertad


The story of Ghana's seizure of the ARA Libertad caught my eye while on my way to Accra last month. It seems that when Argentina's currency peg collapsed about a decade ago, some private creditors refused to accept the government's repudiation of its sovereign debt. In this case, an investment fund called Elliot Management (with court rulings in its favour) has asked Ghana to sieze Argentinean property--in this case, a tall ship.

What has tongues wagging here in Ghana is the announcement that Argentina will now sue Ghana of this seizure.

Elliot claims to be owed $1.6 billion, so without a highly favourable valuation, the Libertad represents only a drop in the bucket.

It seemed odd to me for Argentineans to be hiring Kwesi and Kwabinah as hired muscle. Ghanaians are too happy-go-lucky to make convincing enforcers. Even in the event that a Ghanaian court agrees that the Libertad is fair game for seizure, history here favours a suboptimal outcome for Elliot &c.


"I'm here for the money you owe my boss! But if you don't have it, that's okay too."

On my first trip here (in 1996), there were highwaymen along the main road, with a noted concentration near Liberian and Leonian refugee camps. Other highwaymen could be encountered on roads all over Ghana, and a common trick was to pound nails through sandals which would be left on the road. When the vehicles stopped to repair tire damage, the thieves would strike.

The encounters went something like this:

"Hand over all your money!"
"Here."
The villains move off.
"Wait! You can't just leave me out here in the middle of the forest with flat tires".
The villains return. They help the victim repair his tires. The villains start to leave.
"Wait! I don't have enough petrol to return home!"
The villains return. They give the victim money for fuel. The villains start to leave.
"Wait! I don't have any money for food on the road!"
The villains return. They give the victim money for food. The villains start to leave.
"Wait! I am going to need a drink with my meal to calm my nerves after this robbery!"
The villains return. They give the victim money so he can buy a beer (or alternatively, apeteshie).
The villains leave, possibly with less money than they started with.

In Ghana it is not uncommon for a Ghanaian to find that he owes the government some heavy sum. But the difference between the stated debt and what is finally paid can be immense--and usually in favour of the Ghanaian. That is because the government here--or, rather, its agens--recognize that they can't destroy someone's livelihood just to collect an arbitrary debt. So debt repayment becomes a negotiation--sometimes a very long one--with a lot of compromise on both sides.

That probably seems incredible to someone in North America or Europe, but it is the reality here where the government's ability to pursue its "creditors" is extremely limited.

The Ghanaian court is apt to look at this whole scenario, and rule that due to the trouble this ship represents, Elliot (or its sub, NML) upon taking delivery of the ship will be paid in full. Of course, they can only take delivery after paying the docking fee and the storage fee at Tema. Then they will have to pay a fee for the security provided by the government of Ghana while the ship was in storage. Then there will be the release fee, the exit fee, the immunization fee for whatever crew are brought in to take the ship back to New York . . .

Sunday, November 11, 2012

Gold-silver five-year four-step

It's a dance.


Four steps over the last five years (since the beginning of 2008). Date annotations are mmyy. As before, I have used a one-year lag and a three-point moving average for the gold-silver ratio.

Last time we were here things didn't go so pleasantly. 

Thursday, November 8, 2012

The creeping death of a fishery: Ghana (1980-2012)

On the short cool afternoons on our complex outside of Accra, we go up on the balcony, beverage in hand, and contemplate the sea.



Unfortunately the view isn't as good as it used to be, as there has been an explosion of building along the coast, especially hotels. In particular, hotels between us and the beach. So the picture above (taken last year) is not exactly current. But you can occasionally get a glimpse of the fishing boats returning in the afternoon between the block wall that now obscure our view.

Here's how it works. Around sunset, the fishing boats sail off and in the late morning--or possibly the afternoon, they return. The fishing is still pretty good near Accra if you go far enough offshore. The late upwelling has prolonged the good catches this year.

But fishing is meager in the eastern and central portions of Ghana. There used to be far more boats plying their trade than do now.

The artisanal fishery is of critical importance. Nearly 25% of Ghana's population lives in the coastal zone. Until the past decade, approximately 10% of the population depended on the fishery for their livelihood (Quaatey, 1996). It seems that that number has declined in recent years. I recall seeing estimates exceeding 30% for the amount of protein in the Ghanaian diet that came from the sea.


Climatic fluctuations over the past fifty years are reflected in the catches of artisanal fishermen (Minta, 2003), but it is not as clear whether the more or less monotonic decline in fish catches over the past decades can entirely be laid at the feet of climate change. Different species respond in different ways to climatic fluctuations--the most important being temperature, rainfall, and strength and duration of upwelling. But against climate change we need to consider the backdrop of changing technology in both the artisanal and mechanized fishing fleets.

In 1996, when I began work in coastal Ghana, I saw significant fishing fleets at many villages along the coast. In particular, the village of Nakwa, at the mouth of the Nakwa River, behind a lagoon fronted by an impressive sand barrier, had a large fishing fleet full of vessels at least sixty feet in length which landed on the barrier. The fishing boats were brightly painted and festooned with colourful banners. There were ferries constantly running across the lagoon between the village and the landing ground for the fishing fleet.

Two years ago I ran a sidescan sonar survey out of Nakwa between the river mouth and the offshore oil platform (GNPC-Saltpond). The fishing fleet was gone, but for a couple of dilapidated wrecks drawn up on shore. The locals told me there was no more fishing--anyone from the village who wanted to fish had to travel 150 km west to Axim, where the fishing was still good.


Nakwa lagoon in 2010.


Flaring gas near Saltpond.

In 1997, in the course of offshore work near Axim, we encountered the artisanal fishing fleet several km offshore at night. The canoes all used lights to lure the fish in where they could be netted. At the time, this was the most technologically sophisticated method of artisanal fishing. Since then, new technologies have been deployed, including underwater lights and the use of chemicals.

The use of technology by the artisanal fishing industry varies from locality to locality. In the far west of Ghana, there has been an attempt to manage the fishery by limiting certain methods (CRC), but such efforts are nearly always local.

This year (so it has been reported), the fishing has ceased off Axim, and the fishermen have been forced further west to Cote d'Ivoire.

Overshadowing the increased efforts of the artisanal fishery is the steady increase in industrial fishing effort.

In 2010 I observed pair-trawling (which is illegal in most places). Sidescan surveys show that the seafloor is crossed by abundant trawl marks, even in nearshore areas that are supposed to be off-limits to such techniques. Trawling disturbs large areas of the seafloor, reducing marine productivity for years.

As the trawling has entered into the waters which were reserved for the artisanal fishermen, it is little surprise that the inshore fishery has suffered.


References


[CRC] Coastal Resources Center / Friends of the Nation (2011). Assessment of Critical Coastal Habitats of the Western Region, Ghana. Integrated Coastal and Fisheries Governance Initiative for the Western Region of Ghana. Coastal Resources Center, University of Rhode Island,132 pages.

Minta, S. O., 2003. An assessment of the vulnerability of Ghana's coastal artisanal fishery to climate change. M. Sc. thesis, University of Tromso, Norway.

Quaatey, S. N. K., 1996. Report on the synthesis of recent evaluations undertaken on the major fish stock in Ghanaian waters. Marine Fisheries Research Division, Fisheries Directorate of the Ministry of Food and Agriculture, Tema, Ghana.

Wednesday, November 7, 2012

Melcom building collapses in Achimota (Accra)


A six-story building collapsed in Accra today. It is the first time such a thing has ever happened.

The principal tenant of the building, occupying the lower three floors, was Melcom, a department/grocery
store (think of something like Walmart).

Luckily the building collapsed before opening, otherwise there would have been hundreds of people trapped
inside. As it is, about 55 employees were inside the building when it collapsed. One report says that 48 people have been removed from the ruins, with only five deaths. Furthermore, there are still people inside calling on cellphones asking for help and water, so it seems that the number of deaths will be much smaller than first assumed.

I've been watching images of it all day on one of the local channels. The building completely pancaked except for part of the ground level (or perhaps it was the basement). The concrete slabs of all of the remaining floors have all piled on top of one another, with the external support columns failing outward. It is as bad as any collapse I have seen after an earthquake. I would put it up there with Armenia (1988). It is still too early to be sure, but I would suspect faulty building materials (also the case in the Armenian earthquake).

The building was considered to be a fine example of a high-tech building. It was built in only two months, using new (to Ghana) construction techniques, but the reporting has been unclear as to the identity of the builder.

We have built a few small buildings ourselves in the course of our project here in Ghana. In general, the quality of available concrete block is very poor, with many block-makers using inadequate amounts of cement to bind together material that includes sticks, grass, leaves, and charcoal.


Block factory production in Weija (note sticks).


Wall in Weija made with low-quality block.

During today's coverage, the reporters revealed that Accra is in an earthquake zone, and cast doubt as to whether many of the modern buildings recently constructed have been built to a standard suitable for one. Furthermore, the same company that built the collapsed building has also built buildings in downtown Accra, which is making some people nervous.

Update Nov. 8 6:40 p.m. local

They are now saying 69 people have been rescued alive from the collapsed building, along with eight deceased.

An Israeli rescue team has arrived with sniffer dogs and various listening/looking devices to look for more survivors.

The owner of the building has been asked to turn himself in (but has not taken up the offer--no surprise there).

I had avoided comments on the age of the building in the original post, as there was too much conflicting information, with some sources saying the building had been recently completed in only two months, while the tenant claimed to have rented the building for ten years. It seems that the tenant has rented the building for ten years, but recently had three floors added to it--this new construction was done in only two months.

Such a project would raise concerns in my mind. Given the nature of the ground conditions (laterite/sand)--was the original low-rise situated on a slab which was adequate for a two-story building but not a five-story one?

Update Nov. 9 evening

More struggles with power and internet. Joy News reports 75 rescued and 10 fatalities, but still numerous survivors known to be in the wreckage, some of whom have been communicating by cell phone.

Freudian slips on Aljazeera

Some observations on the election from a commentator on Aljazeera (on TV here in Accra).

"Clearly a majority of voting Americans felt that Barack Obama diseas . . . deserved a second term as President."

"Obama's victory was sealed as he won several key backwa . . . battleground states."