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 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:

4. Contact Information: Maritime GPS disruptions or anomalies should be reported immediately to the NAVCEN at 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

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.

Links :

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.

Links :

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.

Links :

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.