Tuesday, September 29, 2020

How does climate change affect the ocean?

A polar bear and her cub on sea ice in the Arctic north of Svalbard
(Image © Larissa Beumer / Greenpeace)

From China Dialogue by David Adam

The ocean has cushioned the blow of global heating, but at a cost to the stability of climate systems and marine life

As climate change tightens its grip, the effects are being felt across the planet.
The global ocean plays a key role and has so far soaked up most of the carbon dioxide and excess heat human activities have produced.
But it is also vulnerable.
Already some significant changes are underway, and the climate disruption to our seas looks set to worsen.

1. Rising temperatures

About 90% of the excess heat trapped by atmospheric greenhouse gases is eventually soaked up by the world’s oceans.
Because oceans are so big, the temperature change to the seawater can seem small – the sea surface layer has warmed by just over 0.5C in the last century.
That’s still enough to cause significant disruption, and the warming is accelerating.

Things expand as they warm, becoming less dense and taking up more space.
The oceans are no different.
Indeed, between 1993-2010, thermal expansion is thought to have raised sea levels by an average of 1.1 millimetres a year, accounting for much of the overall rise we have seen.
The total observed rise in sea level for the 1993-2010 period was an average of 3.2mm every year, with contributions from various other sources, including water stored on land, in forms such as snow.

(Graphic: Manuel Bortoletti / China Dialogue Ocean)

Warmer water also influences the atmosphere above it.
Increased sea surface temperatures are associated with making hurricanes and tropical cyclones more powerful, potentially increasing the number of the most severe category 4 or 5 storms that strike islands and coastal areas.
Warmer water can also dissolve less carbon dioxide, which means more will stay in the atmosphere to accelerate global warming.

Just like on land, rising temperatures in the oceans generate damaging heatwaves.
They occur when unusual weather conditions or water currents cause above-average water temperatures for at least five consecutive days.
But they can last for months or even years.
A marine heatwave called “The Blob” hung around the northern Pacific from 2013-2015 and killed a million seabirds on the west coast of the United States.

2. Acidification

As carbon dioxide dissolves in seawater, it reacts to form carbonic acid: a fairly weak acid, but enough to alter the pH of seawater, which is naturally alkaline.
Since the industrial revolution, dissolved carbon dioxide is estimated to have lowered the average pH of the top layer of the oceans by 0.1 pH units, from about 8.2 to 8.1 (7 is neutral).

That change doesn’t sound much, but because pH is measured on a logarithmic scale, it actually represents a nearly 30% increase in acidity.
This has some significant knock-on effects for seawater chemistry and the ecosystems that rely on it.

(Graphic: Manuel Bortoletti / China Dialogue Ocean)

The increase in acidity is particularly bad news for shellfish and other forms of sea life that use the mineral calcium carbonate to form their shells and exoskeletons.
More acidic water can hold less of this mineral, so there’s less available for so-called calcifying organisms such as oysters, clams, sea urchins, shallow water corals, deep sea corals and calcareous plankton.
Worse, the change in chemistry encourages existing carbonate structures to dissolve.

Coral is particularly vulnerable.
Experiments on a small patch of Australia’s Great Barrier Reef show that artificially reducing the seawater carbon dioxide level, so restoring pH to pre-industrial levels, boosted coral calcification by 7%.
Then, when the scientists raised the amount of carbon dioxide and so decreased ocean pH to the level expected by the end of this century, calcification dropped by a third.

3. Melting ice

As climate change continues, many scientists believe it is inevitable that massive ice sheets in Greenland and Antarctica will collapse and melt entirely, eventually pouring enough water into the oceans to raise global sea levels by several metres.
It will take time – hundreds, perhaps thousands of years – but the melting is accelerating.
The UN’s climate body now projects that, under a low-emissions scenario, average sea level will rise between 61cm and 1.1m by the end of the century.

By 2050, rising seas could push peak high tides above land currently home to at least 300 million people, mostly in Asia.

Villagers in the Sundarbans work to repair a damaged dike after seawater flooded an adjacent paddy field.
This low-lying delta region straddles the India-Bangladesh border.
Home to an estimated 4.5 million people, it is particularly vulnerable to rising sea levels.
(Image © Peter Caton / Greenpeace)

Coastal ecosystems will be affected too.
Beach and dune environments face more severe and frequent flooding and erosion, while sensitive freshwater habitats including mudflats and marshes – needed for bird species to breed – will be swamped with seawater.

Sea ice, which forms when seawater freezes each polar winter, is also melting and thinning more and more each summer.
Melting of this ice doesn’t significantly contribute to sea levels, but it does pose big problems for creatures that rely on it for their habitat.
Most notably, polar bears need sea ice to hunt seals, and studies show many of the 25,000 bears estimated to remain in the Arctic are struggling.
One colony of animals around the Southern Beaufort Sea, in northeastern Alaska and Canada, was found to have declined by 40% between 2001 and 2010.

4. Changes in ocean currents

Ocean currents are vulnerable to the effects of climate change.
At present, those currents act as massive global conveyor belts: as winds push through the atmosphere from the warm equator to the colder poles, they drag surface water with them.
Cooled by the chilly polar air, this water becomes denser, and so sinks to the deep ocean, where it is pushed back towards the equator (becoming warmer, less dense and rising as it goes) by the next batch of denser water coming from above.
Round and round the cycles go, transporting and mixing nutrients as they swirl along.

(Graphic: Manuel Bortoletti / China Dialogue Ocean)

Melting ice interferes with this system.
Huge amounts of fresh water pouring in at the poles lowers the density of the seawater, making it slower to sink.
Without the same driving downward force, the whole global cycle can weaken.
In 2018, scientists suggested that the major current in the Atlantic Ocean had slowed by about 15%.
And some studies predict that could worsen to more than 30% by 2100.

Based on what has happened in the past, scientists say slower ocean currents can bring significant changes in the Earth’s atmosphere, and so to the weather.
Winters in Europe could be much colder (an idea taken to extremes in the film The Day After Tomorrow).
Meanwhile, the waters of the South Atlantic could become warmer, and because sea surface temperature influences wind and rainfall, this could disrupt monsoon cycles that are vital for crops across Asia and South America.

5. Deoxygenation

Ocean creatures rely on oxygen dissolved in seawater, just as we breathe it from the atmosphere.
But climate change is gradually draining oxygen from the seas: about 1-2% is thought to have been lost from 1960 to 2010, and that could rise to 4% by 2100.

There are several reasons.
Warmer water can hold less of the gas, while disruption to ocean currents limits the amount of oxygen transported from the surface to the depths.

A growing problem occurs when the fertiliser and other nutrients added to agricultural soils drain into rivers and eventually get dumped into coastal waters.
Boosted by the unexpected supply of food, algae can grow and proliferate rapidly to form massive floating blooms – sometimes called green (or red) tides.
These can be problematic, for example by releasing chemicals toxic to fish.
And when the algae die and sink, the microbes that work to decompose the blooms in the depths soak up oxygen from the surrounding water.

Gdansk beach in northern Poland was closed to tourists due to a toxic algal bloom in the summer of 2018 (Image: Wojciech Strozyk / Alamy)

In severe cases, dissolved oxygen levels can fall so low that parts of the deep ocean become barren.
A 2008 global survey found at least 405 of these dead zones, up from 49 in the 1960s.
Perhaps most affected is the Baltic Sea.
Despite efforts to limit agricultural run-off from surrounding countries, the Baltic still has a massive dead zone of about 70,000 square kilometres – about the size of Ireland.

6. Marine food chain collapse

Already under pressure from overfishing and pollution, marine life – from large fish down to cyanobacteria – is also affected by climate change.
As seas warm and currents shift, some sea life can simply move, for example towards the cooler water of the poles.
These shifts in distribution have knock-on effects for species that feed on them: from people trying to catch tuna, to fish looking for zooplankton.
Under stress from shifting resources, species are especially vulnerable if they are already weakened by acidification and oxygen depletion.

Changes to interconnected and complex systems of food webs are hard to predict.
Fisheries in some areas might actually get a boost as valuable new species are driven into their nets.
But, overall, the impact is likely to be bad.
A study last year suggested that warmer waters had reduced the total amount of fish that can be caught in a sustainable way by 4% since the 1930s.
The worst-affected sea was the Sea of Japan, with a 35% reduction in fishery size due to warming.
The East China Sea saw a drop of 8%.

(Graphic: Manuel Bortoletti / China Dialogue Ocean)

Future drops in fish catches would threaten the food security of a large fraction of the world’s growing population.
According to the UN, fish provide more than 3.1 billion people with at least 20% of their animal protein.
It’s an important source of fatty acids and micronutrients too.
Fish currently supply 17% of all the protein consumed in the world, and demand is expected to continue to increase as incomes rise in the developing world.

Links :

Monday, September 28, 2020

Seaweed: The food and fuel of the future?

The cold water around the Faroe Islands is good for seaweed cultivation

From BBC by Adrienne Murray

Sunshine has given way to wind and rain, as the motorboat chugs through a fjord in the Faroe Islands.

"Its a bit windy here," says Olavur Gregarsen.
"We'll see how far we can get to the harvesting boat."

We soon reach a sheltered spot where steep mountains are looking down on hundreds of buoys bobbing in the sea.

"They are holding up a horizontal line," explains Mr Gregarsen, the managing director of Ocean Rainforest, a seaweed producer.
"At every metre another line hangs down, and that's where the seaweed grows."

Breaking waves

Anchored to the sea floor, the cultivation rig consists of 50,000m (164,000ft) of underwater lattice-like ropes, designed to withstand rough sea conditions.

"The main structure is 10m down.
That way we avoid the largest breaking waves," he says.

Despite the Danish territory's remote North Atlantic location, Mr Gregarsen says the deep, nutrient-rich, waters are well suited for growing seaweed, with a stable temperature of between 6C and 11C.

Ocean Rainforest plans to double production
Image Adrienne Murray

His firm is among a wave of seaweed farms that have sprung up in Europe and North America, spurred by a growing demand from the food industry and others.

"You have a biomass that can be used for food and feed, and replacing fossil-based products like packaging material from plastic," he says.


Seaweeds are fast-growing algae.
They utilise energy from sunlight, and take up nutrients and carbon dioxide from the seawater.
Scientists suggest seaweed could help fight climate change and offset carbon emissions.

Ocean Rainforest recently won funding from the US Department of Energy to build a similar system in California, where there's interest in developing industrialised seaweed production for future biofuels.

Aboard the harvesting boat the skipper controls a mechanical arm that lifts lines from the water.
The seaweed is chopped free, filling up containers.
It's quick but messy work.
The lines are then left to regrow.
This year around 200 tonnes will be harvested.

Ocean Rainforest recently won funding from the US Department of Energy
Image Adrienne Murray

But the company is scaling up, and plans to double its capacity this year.
It isn't making money just yet, but expects to soon, Mr Gregarsen tells me.
"We can see how we can mechanise this, how we can make this a really large-scale efficient activity," he says.
"There are not many companies that do this as a profitable business, if any."

Cosmetics and medicines

Seaweed needs to be processed quickly.
At a small plant in the Faroese village of Kaldbak, machines clean the harvest.
Some is dried and supplied to food manufacturers.
The rest is fermented and shipped to animal feed producers.

Seaweed is used to make food additives, textiles and fuel
Image Adrienne Murray

Most farmed seaweed is consumed in food, but extracts are used in a wide variety of products.
Whether it is toothpaste, cosmetics, medicines or pet food, these often contain hydrocolloids derived from seaweed, which have gelling or thickening properties.

And more products are coming, with other firms working on textiles and plastic alternatives, including biodegradable packaging, water capsules, and drinking straws.

Seaweed production has boomed.
Between 2005 and 2015 volumes doubled, surpassing 30 million tonnes annually, reports the UN's Food and Agriculture Organization.
It is a business worth more than $6bn (£5bn) worldwide.

Yet only a fraction of cultivation happens outside Asia, where farming is a long-established, but mostly labour-intensive activity.

'A lot of effort'

"The labour cost is really high in Europe, so that's one major part of it," explains Annette Bruhn, who is a senior scientist at Aarhus University in Denmark.
"A lot of effort needs to be put into mechanisation and upscaling."

To make farming economical, she says "the yield needs to go up and the cost needs to go down".

But farming systems aren't easily replicated.
"Different areas in different waters, all require modifications.
There's not one solution that can be expected to fit all," says Ms Bruhn.

Seaweed uses carbon dioxide from the sea
Image Harald Bjorgvin

However, she is hopeful, and says there are "many areas where you can have breakthroughs".

That is what innovators like Sintef are trying to do.
The Norwegian scientific research group is working on new technologies to streamline farming.
"Now most of the seaweed is used for food, but in the future we want to use it for fish feed, fertilisers, biogas.
We need large volumes and we need to produce much faster," says research scientist Silje Forbord.

Dry lab

Prototype machines such as the "seaweed spinner" automatically wrap spools of seedling-carrying threads onto lines, ready for deployment at sea.

Another concept, SPoke (Standardized Production of Kelp), consists of circular farm modules where seaweed grows from lines radiating outwards.
It is designed so a robot can move along the wheel-like spokes - either attaching threads carrying juvenile seaweed or harvesting it.

"We've built one arm with a robot going back and forth.
That has been tested in a dry lab," explains Ms Forbord, but more investment will be needed.

 Land-based seaweed cultivation
No additives or fertilisers are used
Image Algaplus

In a series of ponds and tanks in northern Portugal, AlgaPlus is cultivating seaweed inland.

"It's a much more controlled environment," says managing director Helena Abreu, who thinks there are more advantages compared to farming offshore.
"We maintain the temperature and everything inside the tanks," she says.
"You have year-round production."

Ms Abreu co-founded the firm after spending five years as a marine biologist in the Azores.
Small, high-value seaweeds are produced for food companies, cosmetics makers and high-end restaurants.


Seawater from a coastal lagoon flows into fish ponds.
It is then pumped through a filtration system into tanks growing seaweed.
There's also a hatchery breeding the seedlings.

"We had to innovate from scratch," she says.
These waters are rich in nitrogen, which the algae take up, mimicking nature.
"We don't need to use any additives, no fertiliser.
We use water from the fish to grow our seaweed," she says.

AlgaPlus produces small, high-value seaweeds
Image Algaplus 

Ms Abreu doesn't think availability of land is a limiting factor.
Former salt works and fish farms could be repurposed, she says, pointing out there are hectares of availability in Portugal, France, Italy, Greece and Turkey.

Onshore seaweed farming takes place in Canada and South Africa too.
Micro-algae are also grown in tank systems.

But there are other challenges.
"The main bottleneck is energy cost. Working with tanks you need the pumping and the aeration to keep the water moving," says Ms Abreu.

The firm can't survive on sales alone just yet.
But Ms Abreu is convinced that the seaweed market will continue to grow.
"It's a huge trend," she says.
"Every year there's more and more companies. There are newcomers in all steps of the value chain."

Links :

Sunday, September 27, 2020

A year along the geostationary orbit

A year through the distant eyes of meteorological satellite Himawari-8 – a hypnotic stream of Earth's beauty, fragility and disasters.
Animation of satellite irradiation scan measurements, scientific data by meteorological satellite Himawari-8 courtesy of JMA/BoM/NCI.
Timecodes for meteorological/astronomical events (approximate, list to be completed):
March 9th 2016 Total Solar Eclipse: 4:44
June 2016 Kamchatka Wildfires: 7:26-8:02 (visible as large amounts of smoke emitted from a point in western Kamchatka, eventually filling a large ocean area) - also: June solstice/polar day north pole
July 2016 Super Typhoon Nepartak: 8:37-8:49
Aug 2016 Typhoon Lionrock: 10:43-11:09
Sep 2016 Super Typhoon Meranti: 11:14-11:24
Dec 2016 December solstice/polar day south pole: from 13:25
Attribution note on the data, which the images in this film are based on:
Satellite observations were originally processed by the Bureau of Meteorology from the geostationary meteorological satellite Himawari-8 operated by the Japan Meteorological Agency. Access to this dataset was provided by the National Computational Infrastructure (NCI), which is supported by the Australian Government.

Saturday, September 26, 2020

Submarine sound quizz

Hold your breath, listen and guess who is making those sounds recorded on board submarines!
With the contribution of the French Navy's Acoustic Interpretation and Reconnaissance Centre.

 Whales / Shrimps / Tonerre / Oil tanker / Sperm whale / Offshore platform / Trawl / Dolphins/ Iceberg

To explore the underwater world, you have to use sound because water is practically opaque to light. The propagation and reflection of sound allows the creation of "acoustic images" and the description of the underwater world.
To do this, sounders or sonars are used.

Applications of underwater acoustics:
  • Mapping the seabed and identifying its nature;
  • Underwater detection (military applications: detection and classification of submarines, mines and surface ships, port surveillance);
  • Monitoring and study of the impact of human noise on biodiversity;
  • Surveillance of structures (renewable marine energies, port infrastructures);
  • The study of water mass movements (oceanography)

Friday, September 25, 2020

Scientists baffled by orcas ramming sailing boats near Spain and Portugal

An orca feeding near a Moroccan fishing boat in the Strait of Gibraltar.
Photograph: Patty Tse/Alamy

From The Guardian by Susan Smillie

From the Strait of Gibraltar to Galicia, orcas have been harassing yachts, damaging vessels and injuring crew

Scientists have been left baffled by incidents of orcas ramming sailing boats along the Spanish and Portuguese coasts.

In the deep: a pod of highly intelligent killer whales, or orcas.
Constant harassment by boats affects their ability to hunt, and has a negative impact on their behaviour.
Photograph: Rand McMeins/Getty Images

In the last two months, from southern to northern Spain, sailors have sent distress calls after worrying encounters.
Two boats lost part of their rudders, at least one crew member suffered bruising from the impact of the ramming, and several boats sustained serious damage.

'I've never seen or heard of attacks': scientists baffled by orcas harassing boats

The latest incident occurred on Friday afternoon just off A Coruña, on the northern coast of Spain.
Halcyon Yachts was taking a 36ft boat to the UK when an orca rammed its stern at least 15 times, according to Pete Green, the company’s managing director.
The boat lost steering and was towed into port to assess damage.

Around the same time there were radio warnings of orca sightings 70 miles south, at Vigo, near the site of at least two recent collisions.
On 30 August, a French-flagged vessel radioed the coastguard to say it was “under attack” from killer whales.
Later that day, a Spanish naval yacht, Mirfak, lost part of its rudder after an encounter with orcas under the stern.

1:15 'It broke the rudder!': orcas damage Spanish naval yacht – video

Highly intelligent social mammals, orcas are the largest of the dolphin family.
Researchers who study a small population in the Strait of Gibraltar say they are curious and it is normal for them to follow a boat closely, even to interact with the rudder, but never with the force suggested here.

The Spanish maritime authorities warned vessels to “keep a distance”.
But reports from sailors around the strait throughout July and August suggest this may be difficult – at least one pod appears to be pursuing boats in behaviour that scientists agree is “highly unusual” and “concerning”.
It is too early to understand what is going on, but it might indicate stress in a population that is endangered.

On 29 July, off Cape Trafalgar, Victoria Morris was crewing a 46ft delivery boat that was surrounded by nine orcas.
The cetaceans rammed the hull for over an hour, spinning the boat 180 degrees, disabling the engine and breaking the rudder, as they communicated with loud whistling.

It felt, she said, “totally orchestrated”.
Earlier that week, another boat in the area reported a 50-minute encounter; the skipper said the force of the ramming “nearly dislocated the helmsman’s shoulder”.

‘The noise was really scary. They were ramming the keel, there was this horrible echo, I thought they could capsize the boat.’
Illustration: Andrea Ucini

Boats off Spain damaged in orca encounters

At 11.30 the previous night, British couple Beverly Harris and Kevin Large’s 40ft yacht was brought to a sudden halt, then spun several times; Harris felt the boat “raise a little”.

Earlier that evening, Nick Giles was motorsailing alone when he heard a horrific bang “like a sledgehammer”, saw his wheel “turning with incredible force”, disabling the steering as his 34ft Moody yacht spun 180 degrees.
He felt the boat lift and said he was pushed around without steering for 15 minutes.

It is not known if all the encounters involve the same pod but it is probable.
Dr Ruth Esteban, who has studied the Gibraltar orcas extensively, thinks it unlikely two groups would display such unusual behaviour.

Alfredo López, a biologist from the Coordinator for the Study of Marine Mammals in Galicia, said orcas made their way up the coast each September from the Gulf of Cadiz to chase tuna into the Bay of Biscay.

Morris’s sailing job was abandoned after the boat was lifted for repair, and she was diverted to another delivery.
She is currently sailing down the Spanish coast and in the early hours of Friday a VHF radio warning came in.
“All ships, all ships,” it began.
“Orca just north of Vigo” – five miles from her location.

After her last experience, Morris is a little jumpy, but, as a science graduate with plans to study marine biology, she is concerned for this vulnerable population of orcas and interested to learn more.
She’d just prefer not to get too close a view next time.

Links :

Thursday, September 24, 2020

GPS Interference


 The equipment shows the ship’s position is on land, instead of the actual position 25 nautical miles offshore.

1. Reference: None.
This revised advisory cancels U.S. Maritime Advisory 2020-007

2. Issue: Multiple instances of significant GPS interference have been reported worldwide in the maritime domain.
This interference is resulting in lost or inaccurate GPS signals affecting bridge navigation, GPS-based timing, and communications equipment.
Satellite communications equipment may also be impacted. Over the last year, areas from which multiple instances have been reported include the eastern and central Mediterranean Sea, the Persian Gulf, and multiple Chinese ports.
The U.S. Transportation Command “Message for Industry” at https://go.usa.gov/xdSpq provides additional GPS interference information.

3. Guidance: Exercise caution when operating underway and prior to getting underway.
The U.S. Coast Guard Navigation Center (NAVCEN) and NATO Shipping Center websites contain information regarding effective navigation practices for vessels experiencing GPS disruption.
The information reaffirms safe navigation practices when experiencing GPS disruptions, provides useful details on reporting disruptions, and is intended to generate further discussion within the maritime community about other disruption mitigation practices and procedures.
This guidance also recommends reporting such incidents in real time; noting critical information such as the location (latitude/longitude), date, time, and duration of the outage/disruption; and providing photographs or screen shots of equipment failures experienced to facilitate analysis.
The NAVCEN information is available at: https://go.usa.gov/xQBaU.

4. Contact Information: Maritime GPS disruptions or anomalies should be reported immediately to the NAVCEN at https://go.usa.gov/xQBaw or via phone at 703-313-5900, 24-hours a day.
NAVCEN will further disseminate reported instances of GPS interference in this region to the NATO Shipping Center.

5. Cancellation: This message will automatically expire on March 21, 2021.

For more information about U.S. Maritime Alerts and Advisories, including subscription details, please visit http://www.marad.dot.gov/MSCI.

Links :

WMO verifies -69.6°C Greenland temperature as Northern hemisphere record

From Royal Meteoroly Society

Climate detectives uncover 30-year-old temperature reading

In an article released online today (Wednesday 23 September, 2020) in our Quarterly Journal, the World Meteorological Organization has recognised a temperature of -69.6°C (-93.3°F) at an automatic weather station in Greenland on 22 December 1991 as the coldest ever recorded in the Northern Hemisphere.

The temperature record was uncovered after nearly 30 years by “climate detectives” with the WMO Archive of Weather and Climate Extremes.
It eclipses the value of -67.8°C recorded at the Russian sites of Verkhoyanksk (February 1892) and Oimekon (January 1933).
The world’s coldest temperature record, of -89.2°C (-128.6°F) on 21 July 1983, is held by the high-altitude Vostok weather station in Antarctica.

The WMO Archive of Weather and Climate Extremes includes records such as the world’s highest and lowest temperatures, rainfall, heaviest hailstone, longest dry period, maximum gust of wind, longest lightning flash and weather-related mortalities.

In this July 18, 2011 file photo, a boat steers slowly through floating ice, and around icebergs, all shed from the Greenland ice sheet, outside Ilulissat, Greenland. Climate historians hunting for past temperature extremes have unearthed what the U.N. weather agency calls a new record low in the Northern Hemisphere.
The World Meteorological Organizations publicly confirmed Wednesday Sept. 23, 2020, the all-time cold reading for the hemisphere: -69.6 Celsius recorded on Dec. 22, 1991 at an automatic weather station in a remote site called Klinck, not far from the highest point on the Greenland Ice Sheet
(AP Photo/Brennan Linsley, File)
The weather station at Verkhoyanksk, which previously held the northern hemisphere cold temperature record, hit the headlines when it recorded a temperature of 38°C on 20 June during a prolonged Siberian heatwave.
WMO is currently verifying whether this is a new record high temperature north of the Arctic Circle (a new category for the archive).
That ongoing investigation, following the lead of this evaluation, will also examine possible past occurrences of high temperatures north of the Arctic Circle.

“In the era of climate change, much attention focuses on new heat records.
This newly recognised cold record is an important reminder about the stark contrasts that exist on this planet.
It is testimony to the dedication of climate scientists and weather historians that we are now able to investigate many of these older records and secure a better global understanding of not only current, but also historical, climate extremes,” said WMO Secretary-General Professor Petteri Taalas.

While most climate extreme observations evaluated by the WMO’s Archive of Weather and Climate Extremes have been made within the last few years, occasionally climate historians uncover long overlooked weather data that contain important climate information that must be analysed and verified.
Such was the case with the just-concluded evaluation of a nearly 30-year-old weather record of an automated weather station at the remote Greenland site named Klinck, located at an elevation of 3,105 metres close to the topographic summit of the Greenland Ice Sheet.

The automatic weather station operated for two years in the early 1990s as part of a network established by the University of Wisconsin-Madison to record the meteorological conditions around the Greenland Crest during the Greenland Ice Sheet Project.
In 1994 it was returned to the laboratory for testing and then sent for use in the Antarctic.

This was before WMO began evaluating global extremes, as the World Weather and Climate Extremes archive was established in 2007.
The record came to light only after a WMO blue-ribbon international panel of polar scientists tracked down the original scientists involved.
The committee commended the station’s original project scientists in the careful maintenance of the calibrations and metadata for an observation made so long ago.
Such diligence indicates a high degree of detail and quality of observation.

After extensive analysis of the equipment, observation practices and the synoptic weather situation of December 1991, the panel unanimously recommended acceptance of the observation as valid.

“This investigation highlights the ability of today’s climate scientists to not only identify modern climate records but to play "climate detective" and uncover important past climate records - thereby creating a high-quality long-term record of climate for climate-sensitive regions of the world,” said Professor Randall Cerveny, Rapporteur of Climate and Weather Extremes for WMO.

The WMO investigations also serve to improve the quality of observations through the careful analysis of observation practices and proper equipment selection.

All components of the Automatic Weather Station had to be selected to be able to function in extremely cold conditions, according to George Weidner, who helped design the station.

“On Greenland, all of the sites were installed by snowmobile.
So the Automatic Weather Station had to be packed to survive a traverse over very rough snow surfaces.
Years of packing experience in Antarctica helped us keep our Automatic Weather Station safe and snug on the sleds being pulled by the snowmobiles,”he said.
Unaltered Klinck AWS photograph as photographed in 1994 during a maintenance check.
Photograph by Mark Seefeldt.
Annotated 1990 Klinck AWS installation photograph: a) air temperature probe at 3.3 metres after installation, b) 2.0 – 2.2 metres above snow surface (at time of time of 22 Dec.
1991 -69.6°C temperature observation), c) estimated snow level in July 1992, d) estimated snow level at time of 22 Dec. 1991 -69.6°C temperature observation, and d) lower temperature probe installed at ~0.9 metre above snow surface at installation (became buried in September 1991, based on the AWS data).
Photograph by Dr. Julie Palais

The WMO international evaluation committee consisted of polar science and climate experts from Denmark, Spain, the United Kingdom and the United States.

Links :

Wednesday, September 23, 2020

France & misc. (SHOM) layer update in the GeoGarage platform

166 nautical raster charts updated & 3 charts replaced & 1 new chart added

Tuesday, September 22, 2020

Autumn equinox

Today is the autumn equinox.
Perfect symmetry between the 2 hemispheres that receive the same amount of solar energy over a day with 12 hours of day/12 hours of night.
Can you see the sun's track exactly on the equator in this satellite animation?

This year's Autumnal Equinox falls on 22 September at 14:30 BST.
The equinox is when the centre of the Sun (as viewed from Earth) crosses the Earth's equator.

Curiosities at the chart makers Imray

The protractor engraved with William Heather's name which was probably his personal instrument

From Yachting Monthly by Katy Stickland

Katy Stickland goes behind the scenes at Imray and discovers the treasures held by the nautical publisher

‘Great Andaman where Inhabitants are said to be Cannibals’.
These ominous words hang in the air, which is thick with the smell of old paper, ink and dust as we gingerly leaf through piles of ‘blueback’ charts in the basement of Imray, Laurie, Norie and Wilson Ltd.

Yachting Monthly is being given a tour of the nautical publisher’s HQ in Wych House in St Ives, Cambridgeshire.

We are poring over some of the company’s oldest charts including this one from 1784 of Andaman and the Nicobar Islands in the Indian Ocean.

The chart is marked in black and red ink, with everything in red highlighting an amendment.

A 1784 chart of the Andaman Islands with amendments in red ink. Credit: Katy Stickland

It also includes remarks from one Captain Phineas Hunt, detailing the Nicobar Islands’ channels and harbours as well as where there is an ‘abundance of Hogs & Fowls’, vital information for Merchant Navy ship captains in the 18th and 19th centuries.

Although Imray as it is today was incorporated in 1904, the roots of the three chart publishers that formed it – James Imray & Son, Norie & Wilson and RH Laurie – can be traced back to the mid 1700s.

For centuries these London-based firms, along with a few other companies, were responsible for producing what became known as blueback charts because of the distinct blue manila paper which was used to back them.

This not only strengthened but also distinguished them from the British Admiralty charts, which were published on heavier-weight paper.

These privately printed charts were mainly used by the Merchant Navy; publications for recreational sailors only really became available from the 1890s.

Imray director Lucy Wilsons shows YM some of the firm’s old blueback charts.
Credit: Theo Stocker

By then, competition from Admiralty charts was damaging the traditional private chart trade, a threat that would eventually lead to the amalgamation of the three firms.

It was Norie & Wilson which took the prudent step in publishing Fore and Aft Seamanship for Yachtsmen: With Names of Ropes, Sails, and Spars in a Cutter, Yawl, or Schooner in 1878.

But it wasn’t until after the First World War that recreational sailing started to become the focus of Imray’s business, partly because of the growth of yachting in the UK.

The C and Y series charts were launched in the late 1920s.

Opposite Wych House’s basement are a framed 1962 C4 chart of the Needles Channel to Portland, and a 1947 chart of the London Docks and the River Thames.

Decades later, the yellow and green colouring on the C4 is still almost psychedelic, competing for eye gaze with the vibrant reds and greens used for colouring the London chart.

Some of the early charts feature the routes of ships

The C4 also has some of the same features of the original bluebacks.

Within the chart are smaller charts for Weymouth Harbour, Christchurch and Lulworth Cove.

The addition of large scale harbour plans were always considered good value for money by Merchant seamen, as it meant they didn’t have to buy additional charts, a continuation which was warmly welcomed by recreational sailors.

Today, Imray C charts cover the whole of the British Isles and parts of Europe.

Imray also rewrote some of its pilot books to include anchorages and passages accessible by smaller sailing boats.

Imray still retains the ethos of its founders: to produce charts using accurate hydrographic data

Previously, pilot books had just concentrated on the needs of larger ships.

The Pilot’s Guide to the English Channel and The Pilot’s Guide to the Thames Estuary and the Norfolk Broads were both rewritten by Eric Wilson and published in 1932 and 1934.

The initial success of Imray’s foray into the yachting market was abruptly halted by the start of the Second World War, which saw Imray move its offices from London to Cambridgeshire.

St Ives was chosen because the print works Enderby & Co were based there, and it had lithographic printers large enough to print charts.

Modern and older versions of Norie’s Nautical Tables for astro navigation

Throughout the 1960s and 1970s Imray established itself as a publisher for cruising sailors.

It started producing folded charts, and in 1979 ended the lining of charts with blue manila paper.

In 1999, the first digitally drawn charts using GIS (geographic information system) software were produced.

Recently Imray has undergone another major change in its production system allowing it to develop new products such as Imray Electronic Navigation Charts (ENCs), update products more frequently, align book, chart and digital products more closely with each other and receive and manipulate data more easily.

Despite advances in technology, Imray still retains the ethos of those three original publishers: to produce charts using accurate hydrographic data.

It is appropriate our tour ends in the boardroom, where the portraits of those early founders stare down at us, alongside the tools of their trade.

The brass protractor belonging to Norie’s founder William Heather; Lord Nelson’s favourite chair which was given to Heather by a friend who served with Nelson on the HMS Boreas and the early editions of Norie’s Nautical Tables, still produced by the company.

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NASA-led study reveals the causes of sea level rise since 1900

This aerial photograph shows fast-moving meltwater rivers flowing across the Greenland Ice Sheet, a region that, combined with Antarctic meltwater and thermal expansion, accounts for two-thirds of observed global mean sea level rise.
Credits: NASA

From NASA by Ian J. O'Neill / Jane J.Lee

Scientists have gained new insights into the processes that have driven ocean level variations for over a century, helping us prepare for the rising seas of the future.

To make better predictions about the future impacts of sea level rise, new techniques are being developed to fill gaps in the historic record of sea level measurements.
We know the factors that play a role in sea level rise: Melting glaciers and ice sheets add water to the seas, and warmer temperatures cause water to expand.
Other factors are known to slow the rise, such as dams impounding water on the land, stymying its flow into the sea.

When each factor is added together, this estimate should match the sea level that scientists observe.
Until now, however, the sea level "budget" has fallen short of the observed sea level rise, leading scientists to question why the budget wouldn't balance.

A new study published on Aug.19 seeks to balance this budget.
By gaining new insights to historic measurements, scientists can better forecast how each of these factors will affect sea level rise and how this rise will impact us in the future.

For example, in its recent flooding report, the National Oceanic and Atmospheric Administration (NOAA) noted a rapid increase in sea level rise-related flooding events along U.S. coasts over the last 20 years, and they are expected to grow in extent, frequency, and depth as sea levels continue to rise.

Factors Driving Our Rising Seas 

On reexamining each of the known contributors to sea level rise from 1900 to 2018, the research, led by NASA's Jet Propulsion Laboratory in Southern California, uses improved estimates and applies satellite data to better understand historic measurements.

This infographic shows the rise in sea levels since 1900.
Pre-1940, glaciers and Greenland meltwater dominated the rise; dam projects slowed the rise in the 1970s.
Now, ice sheet and glacier melt, plus thermal expansion, dominate the rise.
Tide-gauge data shown in blue and satellite data in orange.
Credits: NASA/JPL-Caltech

The researchers found that estimates of global sea level variations based on tide-gauge observations had slightly overestimated global sea levels before the 1970s.
(Located at coastal stations scattered around the globe, tide gauges are used to measure sea level height.) They also found that mountain glacier meltwater was adding more water to the oceans than previously realized but that the relative contribution of glaciers to sea level rise is slowly decreasing.
And they discovered that glacier and Greenland ice sheet mass loss explain the increased rate of sea level rise before 1940.

In addition, the new study found that during the 1970s, when dam construction was at its peak, sea level rise slowed to a crawl.
Dams create reservoirs that can impound freshwater that would normally flow straight into the sea.

"That was one of the biggest surprises for me," said lead researcher Thomas Frederikse, a postdoctoral fellow at JPL, referring to the peak in global dam projects at that time.
"We impounded so much freshwater, humanity nearly brought sea level rise to a halt."

Since the 1990s, however, Greenland and Antarctic ice sheet mass loss and thermal expansion have accelerated sea level rise, while freshwater impoundment has decreased.
As our climate continues to warm, the majority of this thermal energy is absorbed by the oceans, causing the volume of the water to expand.
In fact, ice sheet melt and thermal expansion now account for about two-thirds of observed global mean sea level rise.
Mountain glacier meltwater currently contributes another 20%, while declining freshwater water storage on land adds the remaining 10%.

All told, sea levels have risen on average 1.6 millimeters (0.063 inches) per year between 1900 and 2018.
In fact, sea levels are rising at a faster rate than at any time in the 20th century.
But previous estimates of the mass of melting ice and thermal expansion of the ocean fell short of explaining this rate, particularly before the era of precise satellite observations of the world's oceans, creating a deficit in the historic sea level budget.

Ice shelves in Antarctica, such as the Getz Ice Shelf seen here, are sensitive to warming ocean temperatures.
Ocean and atmospheric conditions are some of the drivers of ice sheet loss that scientists considered in a new study estimating additional global sea level rise by 2100.

Credits: Jeremy Harbeck/NASA

Finding a Balance

In simple terms, the sea level budget should balance if the known factors are accurately estimated and added together.
It's a bit like balancing the transactions in your bank account: Added together, all the transactions in your statement should match the total.
If they don't, you may have overlooked a transaction or two.

The same logic can be applied to the sea level budget: When each factor that affects sea level is added together, this estimate should match the sea level that scientists observe.
Until now, however, the sea level budget has fallen short of the observed sea level rise.

"That was a problem," said Frederikse.
"How could we trust projections of future sea level change without fully understanding what factors are driving the changes that we have seen in the past?"

Frederikse led an international team of scientists to develop a state-of-the-art framework that pulls together the advances in each area of study – from sea level models to satellite observations – to improve our understanding of the factors affecting sea level rise for the past 120 years.

The latest satellite observations came from the pair of NASA – German Aerospace Center (DLR) Gravity Recovery and Climate Experiment (GRACE) satellites that operated from 2002-2017, and their successor pair, the NASA – German Research Centre for Geosciences (GFZ) GRACE Follow-On (launched in 2018).
Additional data from the series of TOPEX/Jason satellites – a joint effort of NASA and the French space agency Centre National d'Etudes Spatiales – that have operated continuously since 1992 were included in the analysis to enhance tide-gauge data.

"Tide-gauge data was the primary way to measure sea level before 1992, but sea level change isn't uniform around the globe, so there were uncertainties in the historic estimates," said Sönke Dangendorf, an assistant professor of oceanography at Old Dominion University in Norfolk, Virginia, and a coauthor of the study.
"Also, measuring each of the factors that contribute to global mean sea levels was very difficult, so it was hard to gain an accurate picture."

 The sea ice is surprisingly weak, has lots of melt ponds, and the expedition ship Polarstern was able to easily break through.
Photo: Steffen Graupnerice / MOSAiC

But over the past two decades, scientists have been "flooded" with satellite data, added Dangendorf, which has helped them precisely track the physical processes that affect sea levels.

For example, GRACE and GRACE-FO measurements have accurately tracked global water mass changes, melting glaciers, ice sheets, and how much water is stored on land.
Other satellite observations have tracked how regional ocean salinity changes and thermal expansion affect some parts of the world more than others.
Up-and-down movements of Earth's crust influence the regional and global levels of the oceans as well, so these aspects were included in the team's analysis.

"With the GRACE and GRACE-FO data we can effectively back-extrapolate the relationship between these observations and how much sea level rises at a particular place," said Felix Landerer, project scientist at JPL for GRACE-FO and a coauthor of the study.
"All observations together give us a pretty accurate idea of what contributed to sea level change since 1900, and by how much."

The study, titled "The Causes of Sea Level Rise Since 1900," was published Aug. 19 in Nature.
In addition to scientists from JPL and Old Dominion University, the project involved researchers from Caltech, Université Catholique de Louvain in Belgium, University of Siegen in Germany, the National Oceanography Centre in the United Kingdom, Courant Institute in New York, Chinese Academy of Sciences, and Academia Sinica in Taiwan.
JPL managed the GRACE mission and manages the GRACE-FO mission for NASA's Earth Science Division of the Science Mission Directorate at NASA Headquarters in Washington.
Based on Pasadena, California, Caltech manages JPL for NASA.

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Monday, September 21, 2020

Tracking undersea earthquakes helps scientists study ocean heating

A team of seismologists and oceanographers has shown that small earthquakes repeatedly emanating from the same spot beneath the ocean floor can help measure changes in ocean temperature.
The quakes generate reliable acoustic signals for measuring ocean temperatures, including at depths below 2000 meters, beyond the reach of other techniques.
If validated, the approach, published this week in Science, could open an entirely new ocean observation system for understanding past and future climate change, says Frederik Simons, a geophysicist at Princeton University unaffiliated with the study.
“There’s a potential treasure trove of data waiting to be analyzed.”

From CleanTechnica by Steve Hanley

Almost every vehicle has a cooling system.
Whether it uses a internal combustion engine or an electric motor, it creates heat while in operation and that heat must be managed to keep the machinery working properly.
If it is not, the radiator may boil over or the battery could catch fire.
Either way, the consequences may be catastrophic.
The world’s oceans are the cooling system for the Earth.
In fact, they absorb up to 95% of the excess heat in the atmosphere.
And if the oceans overheat, the consequences for humanity will be dire indeed.

It is easy to install a temperature gauge in a vehicle’s cooling system to warn if the coolant is getting too hot.
Measuring the temperature of the oceans is much more difficult.
Surface temperatures are relatively simple to monitor but determining the temperature of the deepest parts of the ocean has been almost impossible up until now.
In truth, we know more about the moon, Mars, and the rings of Saturn than we do about the deepest parts of the oceans, where the water can be several miles deep.

In 1951, Rachel Carson published The Sea Around Us, a beautifully written book about the oceans that explained in plain language everything we knew about them at the time.
I read it over the past summer and learned much that I didn’t know about the ocean.
In truth, even though people have stood on the moon since then, our knowledge of the deep oceans has advanced hardly at all since Carson’s book was published.

Oceanographers now have access to the ARGO system, a collection of buoys that can descend up to 2000 meters to measure things like salinity and temperature then rise to the surface where solar powered transmitters send the data to oceanographers around the world.
ARGO is a powerful tool but it covers only a tiny portion of the world’s oceans.
Now scientists at CalTech say they have devised a system that could provide data about deep ocean temperatures and track changes going back decades.

 A global map of earthquake activity.
The earthquakes occur at the boundaries between Earth's tectonic plates.
The colors indicate the depth of the earthquakes, with red being the shallowest and green the deepest. [USGS earthquake catalogue from 2000 to 2008, magnitude of 5.0 M and above.]

How is that possible?
When you hear a siren in the distance, the sound gets higher if the source is getting closer to you, lower if it is going away.
That is known as the Doppler shift.
That shift can be decoded electronically to determine how fast the source of the sound is travelling.
What the scientists at CalTech discovered is that the sounds of undersea earthquakes travel great distances through the water.
But how fast they travel is a function of the temperature of the water they are travelling through.
Carefully measure the amount of time it takes for those sounds to travel underwater and you can calculate the temperature of the water.

And here’s the kicker.
There are recordings of those sounds from some areas of the world that go back decades, so now for the first time it is possible to perform the necessary calculations over a significant period of time and plot the changes.
Jörn Callies is an assistant professor of environmental science and engineering at Caltech and co-author of a study published in the September 18 edition of Science.
He says earthquake sounds are powerful and travel long distances through the ocean without significantly weakening, which makes them easy to monitor.

Wenbo Wu, postdoctoral scholar in geophysics and lead author of the paper, explains that when an earthquake happens under the ocean, most of its energy travels through the earth but a portion of it is transmitted into the water as sound.
These sound waves propagate outward from the quake’s epicenter just like seismic waves that travel through the ground, but the sound waves move at a much slower speed.
As a result, ground waves will arrive at a seismic monitoring station first, followed by the sound waves, which will appear as a secondary signal of the same event.
The effect is roughly similar to how you can often see the flash from lightning seconds before you hear its thunder.

 An artist’s rendering of undersea earthquake waves. Credit: Caltech

“These sound waves in the ocean can be clearly recorded by seismometers at a much longer distance than thunder — from thousands of kilometers away,” Wu says.
“Interestingly, they are even ‘louder’ than the vibrations traveling deep in the solid Earth, which are more widely used by seismologists.” The speed of sound in water increases as the water temperature rises, so the length of time it takes a sound to travel a given distance in the ocean can be used to deduce the water’s temperature.

“The key is that we use repeating earthquakes — earthquakes that happen again and again in the same place,” Wu adds.
“In this example we’re looking at earthquakes that occur off Sumatra in Indonesia and we measure when they arrive in the central Indian ocean.
It takes about a half hour for them to travel that distance, with water temperature causing about one tenth of a second difference.
It’s a very small fractional change, but we can measure it.”

Because the researchers are using a seismometer that has been in the same location in the central Indian Ocean since 2004, they can look back at the data it collected each time an earthquake occurred in Sumatra, for example, and determine the temperature of the ocean at that time.
“We are using small earthquakes that are too small to cause any damage or even be felt by humans at all,” Wu says.
“But the seismometer can detect them from great distances, thus allowing us to monitor large scale ocean temperature changes on a particular path in one measurement.”

The process can detect temperature changes as little as a thousandth of a degree.
Using just the data from the Sumatra area, the researchers say the temperature of the Indian Ocean has risen 0.044 degrees Celsius over the past decade, a result that correlates well with the data provided by the ARGO network.
In fact, the preliminary findings suggest the oceans are warming faster than predicted, although those results are preliminary.

The new research tool is “quite extraordinary and very promising,” says Susan Wijffels, a leader of the ARGO project at the Woods Hole Oceanographic Institute.
What excites here about the new technique is that it allows researchers to examining old seismic records that predate the beginning of the ARGO project.
“What a gift to the climate community that would be,” she says.

Because undersea earthquakes happen all over the world, Callies thinks it should be possible to expand the system to monitor water temperatures in all the world’s oceans..”We think we can do this in a lot of other regions and by doing this, we hope to contribute to the data about how our oceans are warming.” Wu adds that because the technique makes use of existing infrastructure and equipment, it would be quite inexpensive to implement on a global basis.

Of course, having such information available is one thing.
Acting on it is another.
In today’s world, there are any number of powerful corporations who prefer to put masking tape over any global temperature gauge to disguise the danger ahead.
They are only too happy to put profits ahead of people, little realizing that if there are no people, there will be no profits.
There is also an anti-science cult that actively denigrates any and all science.
Either of those forces could delay action to address the factors causing our planet to overheat to the point where corrective action becomes impossible.

Knowing how ocean temperatures are rising is vital information but overcoming the cabal of ignorance and stupidity dedicated to ignoring global heating is even more important.
In the upcoming election, vote as if your life depends upon it, because it does.

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Sunday, September 20, 2020

Huge waves crash against swaying North Sea oil rig

This video could make you seasick...
Huge waves crash against a swaying oil rig, as a severe storm which swept across parts of Scotland hits the North Sea.
The footage of the Borgholm Dolphin installation was captured at the weekend by James Eaton, an offshore worker on the nearby Lomond Platform, around 145 miles east of Aberdeen.

Saturday, September 19, 2020

Image of the week : 5 tropical cyclones over the Atlantic basin

We are issuing advisories on five tropical cyclones over the Atlantic basin.This ties the record for the most number of tropical cyclones in that basin at one time, last set in Sept 1971.

See http://hurricanes.gov for the latest updates. #Paulette #Rene #Sally #Teddy #Vicky

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Friday, September 18, 2020

Chemical tanker grounding and ENC data accuracy

Navigational chart BA2910 (scale 1:500,000)

 Localization with the GeoGarage platform (NGA raster chart)

From TankerOperator

A report by BSU into a chemical tanker grounding gives interesting insight into the importance of understanding the accuracy of electronic chart data.

 Chemical tanker Pazifik (Liquefied gas carrier)

A report by the Germany Federal Bureau of Maritime Casualty Investigation (BSU) of the grounding of 42,000 dwt chemical tanker PAZIFIK in Indonesia in July 2018, published in January 2020, gives interesting insights into the importance of crew understanding the quality of official electronic navigation chart (ENC) data accuracy.

 Voyage planned using ChartCo

The root cause of the accident could be described as the vessel hitting a rock.
The rock was shown on the ECDIS display with a note “underwater rock (always underwater / submerged 1 MAR 2017)”.

 Passage planned using ChartCo

From this, they assumed that the rock was not a hazard, since surrounding water was a comfortable 100m depth.

The crew also thought the vessel was at a safe distance from the underwater rock, since the electronic chart display had a “cross track distance” of 182m either side of the vessel, and the rock was much further away than 182m, according to the ECDIS display.

(The cross track distance is a system on ECDIS displays where vessels are given a safe corridor shown by red and green lines, rather than a specific course, taking uncertainty into account).

 Indonesian navigational chart : ID295 (scale 1:200,000)

 Indonesian navigational chart : ID268-2 (scale 1:50,000)

But in reality the rock was only 9m below the water surface, and located 400m away from where it was stated to be on the ENC.
The ENC’s stated accuracy was +/- 500m.

Indonesian Navigational chart ID295 (scale : 1:200,000)

 Indonesian Navigational chart ID268-2 (scale : 1:50,000)

The rock’s location was also shown accurately on a small scale paper chart mapped in a 1904 Dutch survey, and warnings were published in “Sailing Directions” available onboard. BSU heard from local sources that several other ships have ran aground on the same rock.

The route chosen was recommended by the vessel’s passage planning software.
The vessel's master was familiar with a route through the Lombok Strait, which would have added 200 nautical miles to the voyage.
He decided to take the route recommended by the software to save the 200nm, the Selat Snape strait between Komodo and Banta.

The vessel was loaded with 18,000 tonnes of ammonia – although no cargo escaped because only the forepeak / ballast water tanks were damaged.

It was able to refloat 5 days later after transferring cargo and ballast water to other tanks, and could proceed to a shipyard in Singapore under its own power, supported by a tug.
The repair included renewing 50m of the double bottom.

The company has decided that the vessel will avoid the Selat Sape passage from now on

Voyage according to route planning

 Deviation from route planning up unitil grounding
Navigation background

In its original plan (which was changed due to fishing vessels), the vessel had planned to pass the rock at a distance of 0.7 nautical miles (1300m).

Information stored in the ENC
The following supplementary information is stored for this isolated danger:" Underwater rock (always under water/submerged 1MAR2017)" 

Its ENC was classified as “Zone of Confidence Category C”, which means a position accuracy of +/- 500m horizontally, and “full area search not achieved".

But the ECDIS was set to a cross track distance of 0.1nm (180m) on each side.

This fits company procedures, where it recommends to keep a "cross track distance setting" of 2 x the vessel's beam in confined waters, or just 64.4m, and this passage is considered "confined waters" in the procedural specifications, so the 0.1m (180m) cross track was considered within limits.

There could have been an alarm in the ECDIS that the cross track was set to 180m, while the chart had an accuracy of 500m.

The crew could have brought up data about the chart accuracy on the ECDIS display, including both horizontal and vertical accuracy, such as for submerged rocks.
But it was quite hard to understand how to use it, BSU says.

 Chart p. 138 UKHO Sailing Directions NP34
The electronic version of the UKHO's3sailing directions available on board (e-NP 34, Indonesia Pilot Volume 2) states the following for the Selat Saperoute (6.99): 
"The passage E of PulauBanta is navigable but is seldom used, other than by ferries and other local craft, as tidal streams are strong and fewer anchorages are available [...]." 

If the vessel had been navigating with paper charts, the crew would probably have been more considerate of possible inaccuracies in the chart, and looked up all the “Sailing Directions” if the vessel was going to an area the master was not familiar with.

Or concerns about using paper charts in an unknown area may have led the crew to take on a pilot, who may have had his own accurate soundings map, or had better local knowledge, BSU said.

Sailing directions

The relevant section of Sailing Directions for the strait between Komodo and Banta states "The passage E of Pulau Banta is navigable but is seldom used, other than by ferries and other local craft, as tidal streams are strong and fewer anchorages are available."

The Sailing Direction for the island of Tokohgilibanta states, "a drying rock, 1 mile farther NNW, is small and dangerous; the breakers on it being indistinguishable from the normal overalls and sea conditions in the area."
(Confusingly, on the ENC, the name of the island changes from Tokohgilibanta to Nisabedi when the viewer zooms in).
This description reflects the location of the rock where the vessel ran aground.

A digital version of these sailing directions would have been available onboard, but without any reference to the ENC, which would be required for the computer to connect them.

BSU says that the ECDIS could be described as "not fully engineered" - since it displaces sources of information such as paper sailing directions, without being a consistent replacement for them

 Indonesian ENC

"There are significant differences between traditional voyage planning using paper charts and digital voyage planning using ENCs. Planning a voyage using paper charts often entails referring to sailing directions, the list of lights and pilot charts with proposed routes plotted.”

“Besides drawing on their experience, officers of the navigational watch therefore refer to sources of data other than the navigational chart. Paper charts and sailing directions have developed over centuries and became more accurate in many areas."

"Most of the world's sea areas are looked upon as being inaccurately surveyed, while paper charts only provide an indication of the data of a survey."

"The accident is therefore attributable to the ECDIS and settings specified," BSU says.

More details

The vessel ran aground on a shoal between the islands of Komodo and Banta, Indonesia.

 Waves breaking on rocks

 Rocks above water

It was using a Transas ECDIS, with PassageManager software from ChartCo, with ENCs supplied by ChartCo using data from the Indonesian Hydrographic Office.
It was using voyage planning software "BonVoyage System" (BVS) from StormGeo.

The ChartCo software proposed a route via Selat Sape, passing between Banta and Komodo, going between the tiny islands of Nisabedi and Lubuhtare, which have only 1.5nm between them.
The master and officer decided not to take this route, but instead take a route between the islands of Nisabedi and Banta, which have 2.5nm between them.

BSU looked at the Indonesian and UK Hydrographic paper charts of the region.
The UKHO charts (both 1:500,000) show a "rock awash" symbol, meaning a rock submerged at high tide or temporarily.

The Indonesian smaller scale chart (1:200,000) shows a rock symbol without specifying whether it is sometimes submerged, while the larger scale Indonesian chart (1:50,000) shows a shallow area with water depth of 9m.
This chart was drawn from Dutch surveys carried out in 1904.

 Proper rock designation in official paper charts according to INT1

The ENC shows the shoal 2 cable lengths (400m) from the scene of the accident, with a note saying, "underwater rock (always underwater / submerged 1 MAR 2017)". The general water depth around the rock is about 100m.

The reason for the discrepancy between the ENC and paper chart is not clear.

The ENC has a “Zone of Confidence Category C” (CATZOC) which means “a position accuracy of +/- 500m horizontally, and “full area search not achieved". This data could be fed into the ECDIS to illustrate the range of “cross track distance” needed.

IHO has a Data Quality Working Group looking at options for improve user awareness and presentation of quality data.