Wednesday, January 17, 2018

New Zealand Linz update in the GeoGarage platform

3 nautical raster charts updated
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A fantastical ship has set out to seek Malaysian Airlines flight 370

Norwegian research vessel Seabed Constructor
is one of the most advanced civilian exploration vessel on earth.

From The Economist 

A swarm of submarine drones will scour the depths for the plane

On January 2nd, at 8pm local time, a strange vessel cast off and sailed out of the Port of Durban, in South Africa, heading east.
Her hull was orange.
Her superstructure bristled with antennae—some long and pointy, some sleek, white and domed.
Her stern sported a crane and also a strange gantry, known to her crew as the “stinger”.
Her bow looked so huge and ungainly as to be on the point of tipping her, nose first, into the depths.
And below deck, invisible to those on shore, she carried eight autonomous submarines called HUGINs, each six metres long, weighing 1,800kg, and containing a titanium sphere to protect the sensitive electronics therein from the pressure of the ocean’s depths.

A flaperon from MH370 (foreground) with a Boeing 777 flaperon used for drift modelling research on the MH370 search operation (background).
Image from CSIRO.

The strange ship’s name is Seabed Constructor.
She is a Norwegian research vessel, built in 2014 and owned by Swire Seabed, a dredging and surveying firm in Bergen.
At the moment, though, she is leased to Ocean Infinity, a company based in Houston, Texas.
And the task Ocean Infinity has hired her for is a hard one: to find whatever is left of flight MH370, a Boeing 777-200ER that left Kuala Lumpur on March 8th 2014 with 239 people on board and vanished over the Indian Ocean.

The disappearance of MH370 is one of the great mysteries of modern civil aviation.
The aircraft was bound for Beijing, but changed course suddenly over the South China Sea and broke off radio contact.
It was last detected by radar near the northern tip of Sumatra, heading west-north-west into the open ocean.
Subsequent transmissions to a communications satellite suggested that it crashed somewhere along an arc between 1,500km and 2,700km west of Australia.


The search that followed was the largest in aviation history.
It was mounted by Fugro, a Dutch firm, and paid for by the Malaysian, Chinese and Australian governments.
Over the course of three years Fugro managed to scan 120,000 square kilometres of seabed.
But it found nothing.
The plan is for Ocean Infinity’s search to be paid for, on a “no find, no fee” basis, by Malaysia alone.
Contracts have yet to be signed, but Oliver Plunkett, Ocean Infinity’s boss, has decided to go ahead anyway, to take advantage of the window of good weather that opens in the southern Indian Ocean in January and February.

 Increased-resolution Bathymetry in the Southeast Indian Ocean

Ocean Infinity aims to cover the ground much faster than Fugro did.
In prior cruises in the Atlantic, the firm has, according to Josh Broussard, its technical director, managed to scan 890 square kilometres a day using six autonomous submarines.
With eight, Mr Broussard thinks that the new mission will be able to manage 1,200 a day—enough to have covered the original search area in just 100 days.

The new search area, 25,000 square kilometres of sea floor chosen by investigators from the Australian Transport Safety Bureau (ATSB), is just north of the old one (see map).
Fugro could infer MH370’s crash site only from its final, rather shaky, satellite signals.
Ocean Infinity’s effort has been guided as well by wreckage washed ashore on the coasts of Africa and several islands in the Indian Ocean—hence the more northerly starting point.
Seabed Constructor will reach that starting-point, which is about 35°S, and 2,200km off the coast of Western Australia, on or about January 17th, her crew having conducted a few final tests and calibrations of the HUGIN system en route, using remote-controlled robots to place dummy debris on the sea floor in order to see if the subs can find it.
If searching the patch of ocean designated by the ATSB reveals nothing, then the ship will head farther north, towards the 30th parallel, which some independent experts believe is a better bet.

 
An ocean of interest

Fugro’s search used but a single autonomous submarine, and this was unable to dive below 4,000 metres, meaning it was not always close to the seabed.
The HUGINs carried by Seabed Constructor can, however, go as deep as 6,000 metres.
That permits them to reach most of the sea floor comfortably.
And the fact that there are eight of them means different areas can be searched in parallel, and that some submarines will always be at sea.

The HUGINs will be launched by the stinger, which extends out over the ship’s stern.
Once underwater, the robot craft will communicate with the ship using an acoustic modem.
The ship’s own modem, which will receive these signals, is fixed to the end of a long pole that extends down through her hull into the water.

Each HUGIN comes with a 300kg lithium-polymer battery pack, good for a tour of duty lasting up to 60 hours.
A downward-pointing sonar will map the contours of the seabed beneath the craft, but most of the searching will be done by side-mounted sonars scanning the bed on either side of the craft.
These send out pings and measure the intensity with which they are reflected.
Sand reflects less sound than metal does, meaning metal objects such as aircraft debris are easy to distinguish.
And if something apparently metallic is detected, its nature can be confirmed using an on-board magnetometer.

 Video describing the capabilities of the Kongsberg Maritime Hugin Autonomous Underwater Vehicle

The HUGINs’ search patterns are set by people, but the craft will actually navigate with little reference to their mother ship.
Every so often, the ship will send out a corrective ping to keep them on course.
Mostly, however, they will employ dead reckoning, based on data from accelerometers, to steer themselves autonomously.
They are also capable of picking their way without assistance over sheer underwater cliffs and mountains, and past crevices and gullies, using on-board cameras and machine-vision software.

After its tour of duty, a HUGIN will be lifted back on-board ship and the data it has collected (up to two terabytes, recorded on a waterproof hard drive) downloaded into the ship’s data centre and turned into human-readable maps, a process that takes six hours.
The HUGIN’s battery will be replaced with a fully charged one, any necessary repairs made, and the craft then sent back out into the ocean.


 Video describing the launch and recovery system of the Kongsberg Maritime Hugin Autonomous Underwater Vehicle
 
A team of geologists and hydrographers will then pore over the maps, looking for signs of the missing plane.
Surprisingly, for such a high-tech operation, this stage of the search will be entirely manual.
Every block of sea floor that the HUGINs map will be examined by three sets of human eyes.
Together, this survey team will come up with a list of possible targets, ranked from “E” to “A” (“nothing” to “that’s it”), to present to their bosses.
If the data look good, a HUGIN will be sent down for a second, closer look, cameras at the ready.

What happens next, if Ocean Infinity does locate what is left of the missing aircraft, is unclear.
Friends and relatives of those aboard it will doubtless derive relief from knowing where the flight ended up.
But merely finding the wreckage will not explain what happened on board the plane.
That will require the discovery of the aircraft’s flight recorder.

A rendering of the Seabed Constructor, and HUGIN ‘fre flying’ AUVs.
Image supplied from Ocean Infinity.

That object is therefore Ocean Infinity’s ultimate target.
If it is found on this mission, Mr Broussard says the firm plans to bring it to the surface and then deliver it for analysis to the Australian authorities, who have the technical competence to assess it.
A follow-up trip to examine the wreckage, and even bring it to the surface, would require further authorisation from the Malaysian government.

Seabed Constructor is the most advanced civilian survey vessel on the planet today.
If its array of technology cannot find MH370, then it is likely that nothing will, and that the mystery of MH370 will remain unsolved.
Either way, though, the advance of technology may mean that it is the last such mystery.
As the oceans are watched with ever closer scrutiny, from space and the depths, it is increasingly difficult for anything to get lost in the first place.

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Tuesday, January 16, 2018

Huge oil spill spreads in East China Sea, stirring environmental fears

A collision involving the Sanchi — shown being doused at right before it sank — created what appeared to be the largest tanker oil spill since 1991.
Environmentalists and marine experts are concerned about the oil slick’s threat to sea and bird life in the East China Sea.
CreditTransport Ministry of China, via European Pressphoto Agency

From NYTimes by Gerry Mullany

An oil spill from an Iranian tanker that sank in the East China Sea is rapidly spreading, officials said Tuesday, alarming environmentalists about the threat to sea and bird life in the waterway.


The tanker, the Sanchi, was carrying 136,000 tons of highly flammable fuel oil when it crashed into a freighter on Jan. 6.
On Sunday, the Sanchi sank after a huge blast sent up a great plume of black smoke and set the surface of the water on fire, China Central Television said.

The bodies of three crew members have been recovered, and the remaining 29 were presumed dead, the Iranian government said.
Thirty Iranians and two Bangladeshis were believed to have died.

 The burning Iranian oil tanker Sanchi is seen partially sunk in the East China Sea
off the eastern coast of China on January 14.

The oil slicks from the sunken tanker were growing in size, China’s State Oceanic Administration said Tuesday.
There are now two huge slicks covering 52 square miles, compared with just four square miles the previous day.
Strong winds were pushing the spill toward Japan, away from China, and it was now less than 200 miles from Naha, Japan.

One concern is that, since the Sanchi sank, marine life will be endangered by the fuel oil’s spreading instead of burning off.
And experts are further concerned that the even dirtier bunker fuel powering the tanker will be released into the sea, exposing delicate marine life to the extremely toxic substance.

Greenpeace expressed alarm about the threat to the marine ecosystem in the East China Sea, which is one of the world’s most heavily trafficked waterways, saying the disaster occurred in “an important spawning ground” for fish.
“At this time of year the area is used as wintering ground by common edible species such as hairtail, yellow croaker, chub mackerel and blue crab,” Greenpeace said.
“The area is also on the migratory pathway of many marine mammals, such as humpback whale, right whale and gray whale.”

The tanker was carrying more than one million barrels of condensate, an extremely light crude oil, to South Korea when it collided with the freighter.
When spilled, the condensate can produce a deep underwater plume damaging to marine life.

File photo shows a rescue ship sailing near the burning Iranian oil tanker Sanchi
photo AP

The Japanese Coast Guard said the fire on the surface of the sea was extinguished early Monday.

The Sanchi disaster appears to be the largest tanker spill since 1991, when an unexplained detonation caused the ABT tanker to leak 260,000 tons of oil off the coast of Angola.

Rick Steiner, a marine conservation specialist formerly with the University of Alaska, told The Associated Press that 60,000 to 90,000 tons was likely to have spilled into the sea, calling it “enormous” and “as large as the official estimate of the Exxon Valdez disaster” off the coast of Alaska in 1989.
He also suggested that the Chinese government was likely to be understating the magnitude of the spill.
Hiroshi Takahashi, a fisheries official in Kagoshima Prefecture in Japan, said the government was “monitoring the direction” of the spill because of fears it “could direct towards Kagoshima.”

The deaths of the Iranian crew members on the tanker prompted Iran’s government to declare a day of national mourning on Monday to honor “the brave mariners who died in the course of their mission.”

Eshaq Jahangiri, Iran’s first vice president, said that efforts to recover the bodies of 29 crew members ceased when the tanker sank off the China’s coast on Sunday.

Because of the release of toxic gases in the immediate aftermath of the explosion, there was little hope that the crew members survived, but efforts to recover their bodies had continued, Mr. Jahangiri said.
“Unfortunately, the ship sank and we could not access their bodies.”

 A computer-generated scenario of where the slick will spread.
(Image: National Oceanography Centre)

Officials still don’t know the cause of the collision between the Sanchi and the CF Crystal, a Chinese freighter that was carrying grain.

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Monday, January 15, 2018

US NOAA layer update in the GeoGarage platform

3 nautical raster charts updated
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Is fishing with electricity less destructive than digging up the seabed with beam trawlers?


The pulse trawl: electrodes in the two direction of the gear cause an electric field above the seabed, which stimulate the flatfish so that come up and end up in the net

From The Conversation by Michel Kaiser

While many people may be interested in the sustainability and welfare of the fish they eat, or the health of the environment, fewer probably worry about the effect that trawl fishing – which accounts for 20% of landings – has on the ocean.

For a long time researchers and the industry have been trying to improve trawl fishing practices.
Things have moved on from practices such as beam trawling – where a large net is dragged across the ocean floor – to potentially less invasive and newer methods like electric pulse trawling.
This sees electrical pulses being sent into the seawater to flush out bottom-dwelling fish like plaice and sole, causing them to swim into the path of trawl nets.


Beam trawls have been the focus of environmental concern for decades, as it causes a substantial reduction in the abundance of animals living on the seabed.
These effects can be long lasting if the fishing occurs in areas which are inhabited by long-lived seabed dwelling species such as oysters and sponges.
Beam trawls are also associated with high amounts of bycatch – unwanted fish and other organisms – although the industry and researchers are working on ways to reduce this.

However, the relatively newer electric pulse fishing is not necessarily a perfect solution either.
Though it does not dig into the seabed to the same extent as traditional beam trawling, research has found it can fatally injure other species which may not be the target catch.

So why use this method if it still has its faults?
High fuel costs and EU legislation which has reduced the discarding fish at sea, have renewed interest in the use of electricity in fishing.
Across the world, millions are fed by the fish caught by trawlers so it is unrealistic for trawling to just be stopped altogether, but the variety of negative impacts on the marine ecosystem remain a cause for concern.

 courtesy of WUR / illustration Justin Tiand

For and against

The UK government recently announced an review into the use of electric pulses by foreign trawlers in British waters due to concerns about its potential effects on the environment and bycatch.
Campaign groups have also called on the EU to reinstate a ban on the electrical pulse method, calling it “destructive”.

The current pulse trawls are fine-tuned to catch larger fish (the spine of the fish acts as a conductor), so that bigger fish respond more strongly to the electric stimulus and are more likely to be caught in the nets.
This reduces catch of unwanted species that are less likely to respond to the electric pulse, and also reduces contact with the seabed.

Traditional beam trawls, on the other hand, are fitted with heavy “tickler chains” – horizontal chains strung across the mouth of the trawl – designed to “dig” fish like Dover sole out of the seabed.
Soles curl into a “c” shape in response to the electric stimulation used by pulse trawls, so they can be caught without the use of these “tickler chains”.

 courtesy of Pulse Fishing

Dispensing with the chains means that the gear is lighter, creates less disruption of the seabed, and substantially reduces the amount of other seabed organisms caught – by 75-80% per unit area of the seabed fished.
By not catching the unwanted species, this improves the quality of landed catch too, because skin abrasion is reduced in the net.
Together, improved catch quality and the reduced fuel consumption means greater profitability for the fishermen.

Electric pulse seems like a good idea from this perspective, but studies of its effects on other species of fish – that are not the intended catch – show that larger cod in particular are prone to spinal fractures when in contact with the electric pulses.
Small cod appear to be unaffected.
Cod typically have a low survival rate if they are unintentionally caught in most trawls, so this issue of spinal fracture may be irrelevant if they are caught using either method.


Additionally, though fewer seabed organisms end up in the trawl net when using electricity compared to traditional beam trawling, it is too early to tell whether the creatures remaining on the seabed are affected negatively by contact with the electric stimuli.
Aquarium experiments, have shown that worms and shrimps, for example, recover within seconds following the application of an electric shock.
However, these controlled laboratory experiments take place without natural predators – that may take advantage of a shocked creature – present.

The issues here are not solely environmental.
The pulse trawl fleet has encroached on grounds that historically were fished by fishermen using low impact netting methods, leading to some resentment and conflict with others in the fishing community.

Societal acceptance of any food production method is vital, and at present – for pulse trawling – this is a greater challenge than answering the ecological questions.
This issue could be resolved by more formal zoning of the sea so that pulse trawling is restricted to areas that do not impinge upon traditional low impact fisheries – initiatives which are currently in negotiation.

Taking both society and environment into account, electric pulse trawling may not be an infallible solution, but it might a better way of trawling than the use of traditional forms of beam trawling.

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