Monday, May 14, 2018

Monster 78-foot wave recorded in the Southern Ocean

source : Metocean NZ
Largest wave ever recorded in Souther Hemisphere reached 78 feet (23.8 m) on May 8.
Scientists believe waves in the Southern Ocean may have even reached 82 feet at one point,
but were unable to confirm this.

From Gizmodo by George Dvorsky

At 78 feet tall, and churned by a fierce storm, it’s the largest wave ever recorded in the southern hemisphere, New Zealand scientists report.

“This is a very exciting event and to our knowledge it is largest wave ever recorded in the southern hemisphere,” said Tom Durrant, a senior oceanographer with MetOcean Solutions, in a statement. “So, this is a very important storm to capture, and it will add greatly to our understanding of the wave physics under extreme conditions in the Southern Ocean.”

 An enormous ocean wave reaching 78.1 feet (23.8 meters) in height has just hit Campbell Island.
The previous record-breaking wave in this region was recorded in 2012 when a wave was found to have reached 72.3 feet (22.03 meters) in height in Tasmania.
The intense storm that has lashed the Southern Ocean around New Zealand and Campbell Island will soon be giving surfing enthusiasts in California powerful waves of their own.
 Campbell island with the GeoGarage platform (Linz chart)

The wave was recorded on the night of May 9 by a MetOcean buoy (Campbell island WRB (CIWRB) which is currently floating in the Southern Ocean near Campbell Island about 430 miles (692 km) south of New Zealand.

 Campbell Island Wave Rider Buoy was moored on 2 March 2018 at Campbell Island

The wave reached a height of 78 feet (23.8 meters) as a storm rolled through the region.
The previous record, also recorded by MetOcean Solutions, was a 63.6-foot (19.4 meter) wave that rolled through the same patch of ocean last year.

Simulation of the storm : wind and Mean sea Level pressure (left) and significant wave height (right) passing over New Zealand

The wave was detected by a single solar powered buoy, which samples wave conditions for 20 minutes every three hours.
The intermittent sampling is done to conserve energy.
During the recording period, the height, period, and direction of each wave is measured, and the data is transmitted to a receiving satellite.
Oceanographers with MetOcean Solutions, a subsidiary of the state-owned Meteorological Service of New Zealand (MetService), believe the peak heights of waves were even higher during the storm. Their wave forecast predicted individual waves reaching heights of 82 feet (25 meters).

The Southern Ocean is one of the least-studied areas on Earth.
Its persistent and energetic winds make it an “engine room” for wave development, producing waves that traverse the globe, including the iconic surfing waves that reach the California coast.

The May 9 storm was generated by the easterly passage of a deep low-pressure system, and accompanied by winds reaching 65 knots (75 mph/120 km/h).
These low-pressure storms are typical in the Southern Ocean, and they can strike at any time of the year, unlike in the northern hemisphere where similar storms only happen in winter.

When measuring waves, oceanographers use a metric called “significant wave height.”
It’s a standard value that characterizes sea conditions, and it takes the average of the highest third of a measured wave.
The May 9 storm produced a significant wave height of 48.9 feet (14.9 meters), which is now a record for the Southern Ocean.
But it’s not the biggest ever recorded; that distinction goes to a 2013 North Atlantic wave with a significant wave height of 62 feet (19 meters).
According to the Smithsonian, the largest wave ever recorded was in Alaska’s Lituya Bay in 1958. It measured 30.5 meters (100 feet) and was caused due to a tsunami, which killed five people. The wave snapped 1,700 trees but did not damage much property as there were a very few towns nearby.

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Sunday, May 13, 2018

See what it's like to ride the tallest wave ever surfed

This wall of water has broken the world record as the largest wave ever to be surfed.
Brazilian surfer Rodrigo Koxa surfed the 80-foot wave in Nazaré, Portugal.
The feat took place in November 2017 but the wave and surfer are just now being honored by the World Surf League’s Big Wave Awards.

From National Geographic by  Elaina Zachos

On the same day Rodrigo Koxa surfed a record-breaking wave, another surfer had a close call with death.

Surf’s up for Rodrigo Koxa … way up.

On November 8, 2017, the 38-year-old Brazilian surfer caught an 80-foot-tall wave in Praia do Norte off the coast of Nazaré, Portugal.
On April 28, the World Surf League gave him the Quiksilver XXL Biggest Wave Award padded with a $25,000 prize.
Koxa’s ride also broke a Guinness World Record for the biggest wave ever surfed.
“I'm just so happy and this is the best day of my life,” Koxa said at the awards.
“It’s a dream come true.”

Other winners include surfers Lucas Chianca, Paige Alms, Aaron Gold, and Ian Walsh. British surfer Andrew Cotton, who broke his back after a fall on the same day and in the same place as Koxa’s record-breaking feat, was awarded the Wipeout of the Year Award.

Previously, the record was set by Hawaii’s Garrett McNamara in 2011 with a 78-foot-tall wave off the same coast.
Other surfers have said they broke that 2011 record, but Koxa’s wave was confirmed—experts can measure a wave from trough to crest by comparing it with the size of the people surfing it.
 

Surf’s Up

In the video, a jet ski drags Koxa up the wave.
In less extreme waters, surfers usually paddle up waves before standing up and riding them, but since Koxa’s 80-foot-tall roller is too fast, towing in on a jet ski allows him to get closer.
The jet ski releases him and in seconds, the powerful waters surge up to him.
Koxa barely manages to evade the wave as it rushes like an avalanche behind him.

Koxa is an experienced surfer and escaped unscathed—this time.
In 2014, he had a brush with death at the same beach.
The experience sent him into a four-month slump where he had nightmares, didn’t travel, and got scared easily.

It’s no coincidence that Koxa and Cotton both rode enormous waves at the same beach on the same day.
The beach’s location and geography make it prime territory and a magnet for intrepid surfers.
Although one surfer got away from the wave with a broken record, the other barely got away with a broken back.

Wicked Waves

The waves of Praia do Norte are famous for being among the largest in the world. 
The beach’s westerly location on the European coast allows it to catch wind, and thus ocean swells, from storms that sweep across the North Atlantic.
A deep canyon runs under the surf and points toward the town, which focuses the ocean swells directly toward the lighthouse at the edge of Nazaré. Nazaré Canyon, the underwater abyss, is 130 miles long and as deep as 16,000 feet below the ocean’s surface in some areas.

“The ocean swells get focused in this submarine canyon and have much more energy,” surfer and forecaster Micah Sklut told NPR in 2013.
“So, first you’ve got really deep water, and then as it approaches the shore it gets very shallow, and that enables the waves to climb really, really big all of a sudden.”

Nazaré’s undersea geography make it particularly unique, but it’s not the only place to catch a big wave.
Other popular surfing spots with towering waves are Teahupo’o in Tahiti, Oahu’s Banzai Pipeline, the Cortes Bank near Los Angeles, and Northern California’s Mavericks.

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Saturday, May 12, 2018

James Cook: The Voyages

A visualisation created with GoogleEarth, showing the track of the James Cook's Endeavour voyage of 1768-1771.
The pages from the Endeavour journal are also synchronised with the timeline.
(other view)

From Geographical by Katie Burton and Paul Presley

To reflect the 250th anniversary of James Cook’s first voyage in 1768, this exhibition at the British Library charts the discoveries made by the great explorer

A close look at world maps from the 15th to 18th centuries shows that some European cartographers got one thing very wrong.
A mysterious land mass at the bottom, surrounding what we now know to be Antarctica, reveals the long-held European belief in a ‘Great Southern Continent’.
Finding this land, and securing a friendly relationship with its people, was one of the secret goals of James Cook’s first voyage, in 1768, on the ship HMS Endeavour.

Cook’s chart of New Zealand shows the course of the Endeavour as the ship circumnavigated the North Island and then the South Island.

Over the course of his three voyages Cook was not only able to disprove the notion of the Great Southern Continent, but also to fill in other blank spaces on the map.
A new exhibition, curated by the British Library to coincide with the 250th anniversary of Cook’s first voyage, brings together a huge array of artwork, original maps and handwritten journals from each seminal expedition.

Laid out chronologically, the exhibition moves through each of the voyages, stopping off, as Cook and his crew did, at different islands and previously uncharted lands.
Each new room represents a stop on the first voyage, which began in the South Pacific, landing first at Tierra del Fuego and then Tahiti.
Between each such ‘voyage’ the exhibition’s path takes visitors ‘back to London’ to explore the after-effects, scientifically and politically, of each journey and to set the stage for Cook’s subsequent travels.

What those of us less familiar with Cook’s voyages may not know is that as well as the requisite sailors, he was joined by artists and botanists.
On the first voyage, this was largely down to Joseph Banks, a wealthy landowner and botanist who paid to join Cook on the Endeavour.
As a result, the exhibition is crammed with art that attempts to bring the people and places the crew encountered to life.

'Inhabitants of the Island of Terra del Fuego in their Hut' by Alexander Buchan 1769
(Image: British Library Board)

There are drawings of the Huash people, native to the island of Tierra del Fuego, by Scottish artist Alexander Buchan; depictions of the Maori by Sydney Parkinson, who died on the voyage back to Britain; huge Pacific panoramas and visions of Antarctic icebergs by William Hodges and engravings of tribal ceremonies by John Webber.
Intriguingly, there are also drawings presumed to be the work of Tupaia, a native high priest of Tahiti who joined Cook on the Endeavour as it continued to New Zealand.

Tahitian Scene by Tupaia
(Image: British Library Board)

Natural history also features heavily.
In the New Zealand room we find a depiction of a kangaroo by Sydney Parkinson – the first European to capture the iconic animal.
The accompanying plaque details the party’s discovery of an animal ‘as large as a greyhound, of a mouse colour and very swift’.

There are a small number of specimens on display.
Highlights include a necklace from Tierra del Fuego, a reindeer-skin quiver from the Chukotsky Peninsula, and the mouthparts of a squid, collected by Joseph Banks once he’d disposed of the body in a delicious soup.
Details such as this serve to make the exhibition particularly memorable.

'Entertainments at Lifuka on the reception of Captain Cook' by John Webber 1777

Interspersed among the historic artefacts are videos, specially produced for the exhibition and including the nation’s favourite documentarian, Sir David Attenborough.
It is here that the curators attempt to tackle the troubling side of Cook’s legacy, from imperialism in Australia and violent encounters with the Maori in New Zealand to the beginnings of a devastating fur trade.
In the final such piece, Nick Tupara, an artist of the Ngāti Oneone tribe in New Zealand, speaks directly to camera: ‘I think our people still feel a tension about the whole Cook story, the way it’s told here and the lack of ability to have their say.’

To help provide this necessary context to the subject, the British Library is commissioning a series of accompanying photography exhibits by Pacific groups consulted throughout the curation of the main gallery – the idea being to form a ‘response’ to the main exhibit by those that most felt the eventual ramifications of Cook’s voyages.

This illustration shows Captain James Cook's portrait with his ships.
It is taken from a 19th-centry book about Arctic expeditions.
"Do just once what others say you can't do,
and you will never pay attention to their limitations again."
James R. Cook

It’s certainly to the curators’ credit that they haven’t shied away from the more controversial aspects of Cook’s voyages.
Confronting entrenched viewpoints is very much at the forefront of modern society and to have turned a blind eye to the more worrisome actions of the past would have done the subject a disservice.

That said, despite a conviction at the beginning of the exhibit (in which the introductory video warns that some of what follows may be troubling), there is a sense throughout that the potential for controversy has imbued the entire exhibition with a feeling of reservation.
Aside from the opulent ‘London’ rooms, there’s very little ‘decoration’ in the voyage areas, a surprising sparsity of framing information which can leave those not already possessing a good degree of knowledge of Cook and his journeys feeling somewhat lost as to the context behind many of the exhibits.
Small globes adorn the start of each area purportedly showing the routes, but they’re fiddly to use and can easily be overlooked during busier times, ultimately leaving visitors sometimes feeling a touch lost as to where they currently are along the path of each voyage.
Large wall maps might have served better along with a greater visualisation of background information.

Strangely, the impression is almost as if by wanting to address the more controversial aspects of Cook’s legacy, a potential to offend has held the exhibition designers back.
That not shouting too loudly about Cook’s endeavours is what’s needed when instead a more bold addressing of the issues would have served everyone better.

Nevertheless, the exhibition skilfully interweaves this complex legacy with the wealth of materials on display and the knowledge that Cook unearthed.
The take-home message is that Cook was important, but not without controversy.

 Third voyage

COOK’S THREE VOYAGES

First voyage (1768-1771): The official mission of Cook’s first voyage was to track the planet Venus from Tahiti. Cook travelled first to Tierra del Fuego, an archipelago off the southernmost tip of South America, then on to Tahiti. He then ventured west to New Zealand where he spent six months charting the coast, proving as he went that the land was not a northern extension of the Great Southern Continent, as many had believed. One of the jewels of the exhibition is Cook’s remarkably accurate map of New Zealand. He finished the voyage charting the unexplored eastern parts of ‘New Holland’ (the name given by the Dutch to Australia in the 17th century).

Second voyage (1772-75): Cook was ordered by the Admiralty to sail south from the tip of Africa, once again on the hunt for the missing southern continent. In disproving the existence of the continent once and for all, Cook led the first expedition to ever cross the Antarctic circle.

 Exploration of the South Pole, 1899
showing Cook voyage

Third voyage (1776-80): The third voyage was to be Cook’s last. It was on this trip that he met his end in ambiguous circumstances on the island of Hawaii (indeed, a display of reports written by eyewitnesses to Cook’s demise makes for gruesome reading). The goal of the expedition was to explore the North Pacific and search for a sea passage to the Atlantic – a passage which, like the southern continent, did not exist.

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Friday, May 11, 2018

Canada CHS layer update in the GeoGarage platform

60 nautical raster charts updated
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