Sunday, February 10, 2019

Fake or not

Photographer Tom Peschak was down to the last frames on his roll of film when he captured the photo he'd been waiting for: a great white surfacing behind researcher Trey Snow's kayak.
"Instead of the scientist tracking the shark the shark is tracking the scientist," Peschak says.

From Thomas Peschak website

When I began work ten years ago on a book about white sharks, I had no idea that this project would yield my most well-known image to date.
For more than ten months I worked together with Michael Scholl and scientists at the White Shark Trust to create novel images of white sharks in South Africa that would illustrate current scientific research.
The team observed large numbers of white sharks venturing into extremely shallow water during the summer months.
In order to figure out why, the researchers tracked and observed the sharks’ movements, but were regularly thwarted for two reasons.
First, the inshore realm was treacherous, humped by rocky reefs and sandbanks, which heaved the research boat precariously during an onslaught of large swells.
Secondly, the boat engine's electrical field seemed to affect the sharks' behavior.

I suggested using a kayak as less obtrusive photographic platform to track white sharks.
I was met withcautious enthusiasm, so I was voted to be the one to test the waters.
Even though we repeatedly tested the sharks’ reactions to an empty kayak, the first few attempts at a manned kayak were nerve-wracking.
As I sat in the “yum-yum” yellow sea kayak, a 15-foot (4.5m) great white shark ambled towards me.
However, white sharks are much more cautious and inquisitive than aggressive and unpredictable.
And this proved true with our experiment; at no time did the sharks show any aggression toward us or our little yellow craft.

The story of this particular photograph began on a perfectly calm and glassy sea.
I tied myself to the tower of the White Shark Trust research boat and leaned into the void, precariously hanging over the ocean while waiting patiently.
The first shark came across our sea kayak, dove to the seabed, and inspected it from below.
I trained my camera on the nebulous shadow as it slowly transformed into the sleek silhouette of a large great white.
When the shark’s dorsal fin emerged, I thought I had the shot but hesitated a fraction of a second.
In that moment, the research assistant in the kayak, Trey Snow, turned to look behind him, and I took the shot.
Throughout the day I shot many more similar images, but all lacked the connection of first image.

A developed roll of slide film shows the moments leading up to the picture photographer Tom Peschak refers to as "the ultimate shark scientist picture."

I knew the image was iconic, but I was not prepared for the public response.
When the photograph was first published, it attracted more than 100,000 visitors to my website in 24 hours.
Many thought the photo was a digital fake, and to date there are still hundreds of websites that debate its authenticity.
Not only is the image real, it was one of the last images I took using slide film before transitioning to digital.
All magazines and prints were taken from a high-resolution scan of the slide with no post-production work.
Over the years the image continued to sell and just when I thought it had run its course, the image resurfaced on April 1, 2006.

The French magazine, Le Magazine des Voyages de Peche (The Magazine of Fishing Voyages) published an April Fool’s Day article that told the story of professional fishermen Arnold Pointer from south Australia who accidentally caught a large female white shark in one of his fishing nets.
Instead of killing her, he set her free and named her Cindy.
From that day forward, the shark followed Arnold every time he set out to sea.
In the article, he states, “It’s been two years and she doesn’t leave me alone. She follows me everywhere I go, and her presence scares all the fishes.”
Two years later this hoax was immortalized in a YouTube slideshow, which used my photograph, purportedly showing Cindy the white shark following Arnold in his yellow kayak.
The video received nearly 1.6 million hits and introduced the white shark kayak to a new audience, albeit in an inaccurate if humorous context.

On August 21, 2011, Hurricane Irene battered the Caribbean island of Puerto Rico and flooded many streets.
I could never have imagined that my photograph would make an appearance in this context, except this time it was only the shark, minus the kayak.
On August 24 the shark appeared on a social news website in the form of a photograph taken from the open window of a car driving along a flooded street.
Next to the car was “my” white shark swimming through the flooded streets of Puerto Rico.
The image was then picked up and used in a TV bulletin on Channel 7 News Miami.
A closer examination of the shark revealed that it was identical to the shark following the kayak in my photograph.
It appears that a crafty Photoshop artist superimposed the shark into a scene of a flooded street.
The composite resurfaced again in June of 2012, when a shark tank supposedly burst in a popular mall in Kuwait.
The photo depicted two sharks (one of which was mine) swimming at the bottom of a submerged escalator.
The most recent incarnation appeared in the wake of Hurricane Sandy, which devastated the eastern coast of the U.S.
This time, the shark made the same appearance outside a car window in the flooded streets of New Jersey.
I always look forward to receiving e-mails from friends and family who have spotted the same white shark in a different context.
While I will probably never become a legend in my own right, at least my white shark is well on her way.

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Saturday, February 9, 2019

One breath around the world

Knowing how incredible our deep seas are, famous French freediver Guillaume Nery is showcasing not one but three Philippine dive sites in a 12-minute video that compiles the most jaw-dropping underwater locations around the world.
Some of the most amazing parts of the video include the limestone formations under Barracuda Lake in Coron, Palawan (2:16), an underwater shot in Coron filmed using an upside-down camera trick (5:50), and shots of Davao del Norte’s Sama-Bajau people, who can hunt underwater for as long as 13 minutes at depths of around 200 feet (6:14 mark).
Filming started in April 2017 when Nery, along with his wife-slash-videographer Julie Gautier and photographer Franck Seguin, flew to some of the world’s under-the-radar dive spots.
They also filmed the Yonaguni Monument off the coast of Japan (0:44); the frozen Sonnanen Lake in Finland (3:59); and Cenote Angelita in Yucatán, Mexico (4:41).
Freedivers hold their breath and go underwater for as long as they can without equipment.
Nery, who has broken the freediving world record four times, can dive to 125 meters (410 feet) below sea level.

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Friday, February 8, 2019

Met Office: global warming could exceed 1.5C within five years

2018 was the fourth hottest year in the modern record, part of a decades-long trend of warming.
The record dates back to 1880, when it became possible to collect consistent, reliable temperatures around the planet.
NASA and NOAA work together to track the temperatures, part of ongoing research into our warming planet.

From The Guardian by Jonathan Watts

Lowest Paris agreement target may temporarily be surpassed for first time between now and 2023

Global warming could temporarily hit 1.5C above pre-industrial levels for the first time between now and 2023, according to a long-term forecast by the Met Office.

Meteorologists said there was a 10% chance of a year in which the average temperature rise exceeds 1.5C, which is the lowest of the two Paris agreement targets set for the end of the century.

Until now, the hottest year on record was 2016, when the planet warmed 1.11C above pre-industrial levels, but the long-term trend is upward.

Man-made greenhouse gases in the atmosphere are adding 0.2C of warming each decade but the incline of temperature charts is jagged due to natural variation: hotter El Niño years zig above the average, while cooler La Ninã years zag below.

In the five-year forecast released on Wednesday, the Met Office highlights the first possibility of a natural El Niño combining with global warming to exceed the 1.5C mark.

Dr Doug Smith, Met Office research fellow, said: “A run of temperatures of 1C or above would increase the risk of a temporary excursion above the threshold of 1.5C above pre-industrial levels.
Predictions now suggest around a 10% chance of at least one year between 2019 and 2023 temporarily exceeding 1.5C.”

Climatologists stressed this did not mean the world had broken the Paris agreement 80 years ahead of schedule because international temperature targets are based on 30-year averages.
“Exceeding 1.5C in one given year does not mean that the 1.5C goal has been breached and can be redirected towards the bin,” said Joeri Rogelj, a lecturer at the Grantham Institute.
“The noise in the annual temperatures should not distract from the long-term trend.”

Although it would be an outlier, scientists said the first appearance in their long-term forecasts of such a “temporary excursion” was worrying, particularly for regions that are usually hard hit by extreme weather related to El Niño.
This includes western Australia, South America, south and west Africa, and the Indian monsoon belt.


NASA: the Global temperature anomalies from 1880 to 2017

They also noted that the probability of 1.5C years would steadily increase unless emissions were rapidly scaled back.

“It’s a warning that we’re getting close to that level,” Prof Adam Scaife, the head of long-range prediction at the Met Office, told the Guardian.
“We’re not saying there is a current risk of breaching the Paris agreement.
What we are saying is that for the first time, we are seeing a chance of a temporary rise of 1.5C due to a combination of global warming and natural climate variation.”

The Met Office said previous results had demonstrated the accuracy of such “decadal reports”, which cover the ground between short-term weather forecasts and long-range climate models.

Since 2014, the world has experienced the four hottest years since records began in 1850, but these highs are likely to be exceeded soon.
From now until 2023, the Met has 90% confidence that mean annual temperatures will range between 1.03C and 1.57C above pre-industrial levels.

The recent United Nations Intergovernmental Panel on Climate Change report on warming of 1.5C, highlighted the calamitous difference even a fraction of a degree above could make to coral reefs, Arctic ecosystems and hundreds of millions of lives.
Starting now, the report said emissions would have to be cut by 45% by 2030 to have any chance of holding to that level.

“Breaching 1.5C of global warming does indeed mean that we failed to limit warming to that ‘safe’ level, but not that our understanding of a safe level of climate change has suddenly changed and climate change should go unchecked,” said Rogelj, who was was a coordinating lead author on the UN report.
“Every tenth of a degree matters. So if 1.5C of global warming would be exceeded for whatever reason, this would be a call for steeper emissions reductions.”

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Thursday, February 7, 2019

NOAA announces change in channel depths on raster nautical chart products


From NOAA

NOAA’s Office of Coast Survey recently announced plans to change the U.S.
Army Corps of Engineers (USACE) maintained channel depth values on raster nautical chart products, which include paper nautical charts and the corresponding digital raster navigational charts (NOAA RNC®).
Minimum depths (also called controlling depths) are collected during periodic USACE sonar surveys of channels.
In the past, these depths were provided on raster charts, but controlling depths will now be replaced with the original channel design dredging depths used by the USACE (called project depths).
Standardizing depth presentation on these products will improve data consistency and overall safety.
Implementation begins in early 2019.

NOAA’s suite of electronic navigational charts (NOAA ENC®) are not affected by these changes.
Mariners are encouraged to use NOAA ENCs for critical safety information as these products are typically updated up to one month ahead of raster products.

Why the change?

The USACE makes the depth information from recent surveys publicly available on their website before NOAA nautical products are updated and published.
NOAA prioritizes making updates to ENC over RNC products.
This often results in RNC products not accurately reflecting the most current controlling depth values (as represented on NOAA ENC and the USACE website).
To eliminate inconsistencies among controlling depths, NOAA will only show project depths on raster chart products in the future.
The Initial implementation of this change will focus on deep draft shipping channels where the primary product used for navigation is the ENC.

How will mariners be notified?

NOAA first publicized the concept of charting project depths in the National Charting Plan released in February 2017.
As the changes are made on individual charts, NOAA will include a note on each chart directing mariners to review the USACE website and use NOAA ENC to access the latest controlling depths.
Additionally, a statement drafted jointly by Coast Survey and the U.S.
Coast Guard (shown below) is being published weekly in the Coast Guard’s Local Notice to Mariners

NOAA recommends that mariners take advantage of the most recent chart updates by using the NOAA Electronic Navigational Chart (ENC) for navigation in U.S. waters.
ENCs provide the most up to date information, whereas paper and raster nautical chart updates may
be up to one month behind the corresponding ENC coverage.
Over the next few years, mariners will see continued improvement in the extent and detail of ENC coverage, while there will be a reduction in RNC and paper chart coverage and service.
ENCs will include routine changes between editions that are not published through
notices to mariners.
One significant change to the RNC and paper charts will be the removal of controlling (minimum) depth information from many maintained channels.
Controlling channel depths will still be provided on ENCs. Comments or concerns can be addressed through ASSIST, NOAA’s
Nautical Inquiry and Comment System.
https://www.nauticalcharts.noaa.gov/customer-service/assist/
Project depths and controlling depths defined

Federally maintained channels are broken into a series of individually named sections called “reaches.” There are two different depths associated with each reach that are reported by the USACE, the project depth and the controlling depth.
Project depths are the original design dredging depths of a channel reach constructed by the USACE.
They may or may not be maintained by dredging after completion of the channel.
In other words, the actual depth of the channel may be shoaler than the project depth (for example, Reach B in image below).
Controlling depths, or minimum depths, are the least depths within the limits of a channel reach.
These depths are updated with each new USACE survey.
Minimum depths restrict the safe use of a channel to ships with drafts less than the minimum.

Example of a federally maintained channel with a project depth of 30 feet.
Reach A has a controlling depth of 32 feet and Reach B has a controlling depth of 28 feet.

Displaying project depths on raster charts

Controlling depths are depicted on raster chart products by channel tabulations, depth legends, and hydrography (individual depth soundings).
Here are a few examples of how depiction of channel depths will change on raster charts:

Channel tabulation to project depth legend:


Depth legend to project depth legend:


Hydrography to project depth legend:


Controlling depth channel tabulation to project tabulation:

Project Depth Note:

The following note will be added to raster charts as controlling depths are replaced with project depths:
PROJECT DEPTHS

Channel legends and tabulations, where indicated, reflect the U.S. Army Corps of Engineers (USACE) project depths.
The channel may be significantly shoaler, particularly at the edges.
For detailed channel information and minimum depths as reported by USACE, use NOAA Electronic Navigational Charts.
USACE surveys and channel condition reports are available at
http://navigation.usace.army.mil/Survey/Hydro.
The change from showing – often outdated – controlling depths to showing channel project depths on raster nautical chart products, such as paper nautical charts and RNCs, will provide greater clarity and safety for mariners.
The project depths shown on raster charts will give users an idea of the original channel design dimensions.
The up-to-date controlling (minimum) depths provided on NOAA ENCs and on the USACE website (referenced on raster chart products) will give users the latest information on the safe depth in which ships may transit through federally maintained channels.
Comments or concerns about these changes can be addressed through NOAA ASSIST.

Diagramming the deep: Navy-sponsored scientist awarded for sea-floor mapping

Publicly available multibeam data included in the Global Multi-Resolution Topography Synthesis covers only about 8 percent of the seafloor, (unshaded areas), although coverage is higher over continental margins and plate boundaries.
Credit: image from the Global Multi-Resolution Topography Synthesis,
hosted by the IEDA Marine Geoscience Data System.

From Eurekalert by ONR

For creating the most comprehensive global map of the ocean floor, Dr.David Sandwell received the Charles A. Whitten Medal, sponsored by the American Geophysical Union (AGU).

Sandwell, a geophysicist at Scripps Institution of Oceanography, accepted the award at the AGU Fall Meeting in December 2018.
Named after scientist Charles A. Whitten, the medal is given to honor "outstanding achievement in research on the form and dynamics of the Earth and planets."

Since the 1990s, sponsored by the Office of Naval Research (ONR), Sandwell has combined satellite data with acoustic depth measurements to develop a detailed, accurate map of the sea floor--painting a vivid tapestry of the deepest, least explored parts of the ocean.
The map catalogues thousands of previously unidentified underwater mountains, trenches, physical undersea connections between South America and Africa, and extinct ridges that spread the sea floor in the Gulf of Mexico.

"Dr. Sandwell's groundbreaking work provides the first high-resolution map of the ocean floor," said Dr. Tom Drake, head of ONR's Ocean Battlespace and Expeditionary Access Department.
"This has opened new research areas for oceanography, marine geology and geophysics--critical topics for the U.S. Navy."

 About 8 percent of the seafloor has been mapped to 100-meter resolution like this.
Source: GeoMapApp

Sandwell's work relies on satellite altimetry (radar) to measure small bumps and dips on the ocean surface, which point to large-scale features on the ocean floor.
For example, undersea mountains are huge enough to exert gravitational pulls that gather water in a bump on the sea surface.
In contrast, massive cracks and rifts on the ocean floor have less gravitational attraction, resulting in a dip on the surface.

For utmost accuracy, Sandwell blends satellite measurements with traditional sonar soundings from manned research ships.
This enables him to compare the topography of the sea surface with that of the sea floor and form a complete map of the bottom.

Sandwell created multiple versions of his map over the last two decades.
He unveiled the first in 1997, based on marine gravitational data gathered by the Navy's GEOSAT Earth-observation satellite.
In 2014, he improved the original map by adding data from additional satellites operated by the National Aeronautics and Space Administration (NASA) and the European Space Agency.

"Dr. Sandwell's map is like a smart phone that improves with each new model," said Dr.
Reginald Beach, who sponsors Sandwell's work for ONR's Ocean Battlespace and Expeditionary Access Department.
"Each version teaches us more about the topography of the ocean bottom, which is crucial to safe navigation for the Navy."


Sandwell is now updating the 2014 map with information gathered by another pair of satellites run by NASA and the French space agency, CNES.

Other data comes from sonar soundings compiled by Australia, during that nation's participation in an international effort to scour the southern Indian Ocean in search of the wreckage of Malaysian Airways Flight 370--which disappeared in 2014.
Australia made the sonar data publicly available in 2017.

In the search for MH370, Geoscience Australia applied a GIS solution to support the world’s largest marine survey, mapping the seafloor in greater detail than ever to provide scientific insights.

"Thanks to this new data, our map can provide greater information about the world's oceans," said Sandwell, "particularly the Southern Hemisphere, which includes the Indian Ocean and south Atlantic Ocean.
I'm grateful to ONR for its valuable support over the years, which has been crucial to creating the most accurate sea floor map possible."

AGU is a not-for-profit, scientific organization with nearly 60,000 members in 139 countries.

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