Showing posts with label marine. Show all posts
Showing posts with label marine. Show all posts

Thursday, September 14, 2017

Offshore wind power cheaper than new nuclear

The cost of subsidies to the UK’s offshore wind farms in contracts awarded in auctions dropped more than 50 per cent and is now well below the price the government has guaranteed for energy from the planned Hinkley Point nuclear power plant
 
From BBC by Roger Harrabin

Energy from offshore wind in the UK will be cheaper than electricity from new nuclear power for the first time.

The cost of subsidies for new offshore wind farms has halved since the last 2015 auction for clean energy projects
Two firms said they were willing to build offshore wind farms for a guaranteed price of £57.50 per megawatt hour for 2022-23.
This compares with the new Hinkley Point C nuclear plant securing subsidies of £92.50 per megawatt hour.
Nuclear firms said the UK still needed a mix of low-carbon energy, especially for when wind power was not available.

 Wind farms offshore UK with the GeoGarage ENC platform (UKHO data)

'Truly astonishing'

The figures for offshore wind, from the Department for Business, Energy and Industrial Strategy, were revealed as the result of an auction for subsidies, in which the lowest bidder wins.
In the auction in 2015, offshore wind farm projects won subsidies between £114 and £120 per megawatt hour.

Emma Pinchbeck, from the wind energy trade body Renewable UK, told the BBC the latest figures were "truly astonishing".
"We still think nuclear can be part of the mix - but our industry has shown how to drive costs down, and now they need to do the same."

Bigger turbines, higher voltage cables and lower cost foundations, as well as growth in the UK supply chain and the downturn in the oil and gas industry have all contributed to falling prices.
The newest 8 megawatt offshore turbines stand almost 200 metres high, taller than London's Gherkin building.
But Ms Pinchbeck said the turbines would double in size in the 2020s.

 from NewScientist (July 2016)

Nuclear 'still needed'

However, the nuclear industry said that because wind power is intermittent, nuclear energy would still be needed.
Tom Greatrex, chief executive of the Nuclear Industry Association, said: "It doesn't matter how low the price of offshore wind is. On last year's figures it only produced electricity for 36% of the time."

EDF, which is building the Hinkley Point C nuclear plant, said the UK still needed a "diverse, well-balanced" mix of low-carbon energy.
"New nuclear remains competitive for consumers who face extra costs in providing back-up power when the wind doesn't blow or the sun doesn't shine," the French firm said.
"There are also costs of dealing with excess electricity when there is too much wind or sun."
EDF added that energy from new nuclear plants would become cheaper as the market matures, as has happened with offshore wind.

Eyes will be raised at this suggestion, as nuclear power has already received subsidies since the 1950s.
But storage of surplus energy from offshore wind is still a challenge.

World's first floating offshore wind farm in Scotland :
Each wind turbine is taller than Big Ben and the farm can power 20,000 homes.

'Energy revolution'

Onshore wind power and solar energy are already both cost-competitive with gas in some places in the UK.
And the price of energy subsidies for offshore wind has now halved in less than three years.

Energy analysts said UK government policy helped to lower the costs by nurturing the fledgling industry, then incentivising it to expand - and then demanding firms should bid in auction for their subsidies.

Minister for Energy and Industry Richard Harrington said: "We've placed clean growth at the heart of the Industrial Strategy to unlock opportunities across the country, while cutting carbon emissions.
"The offshore wind sector alone will invest £17.5bn in the UK up to 2021 and thousands of new jobs in British businesses will be created by the projects announced today."

Michael Grubb, professor of energy policy at University College London, called the cost reduction "a huge step forward in the energy revolution".
"It shows that Britain's biggest renewable resource - and least politically problematic - is available at reasonable cost.
"It'll be like the North Sea oil and gas industry: it started off expensive, then as the industry expanded, costs fell. We can expect offshore wind costs to fall more, too," he said.

The subsidies, paid from a levy on consumer bills, will run for 15 years - unlike nuclear subsidies for Hinkley C which run for 35 years.
This adds to the cost advantage offshore wind has now established over new nuclear.

 Wind farms offshore UK with the GeoGarage ENC platform (UKHO data)

Prof Grubb estimated the new offshore wind farms would supply about 2% of UK electricity demand, with a net cost to consumers of under £5 per year.

Caroline Lucas, co-leader of the Green Party, said: "This massive price drop for offshore wind is a huge boost for the renewables industry and should be the nail in the coffin for new nuclear.
"The government's undying commitment to new nuclear risks locking us into sky high prices for years to come. Put simply, this news should be the death knell for Hinkley C nuclear station."

Along with three offshore wind farm projects, biomass and energy from waste plants have secured subsidies for low-carbon energy, with a total of 11 successful schemes in the latest auction.

The £57.50 for new offshore wind power is not a true subsidy.
It is a "strike price" - a guaranteed price to the generating firm for power it supplies.

When the wholesale market price for electricity is below that price, payments to the firm are made up with a levy on consumers.
However, when the wholesale price is above the strike price, the generator pays the difference back. It is a way of providing a certain return on investment for large energy projects.
It is impossible to predict what the final additional cost to consumers will be because it depends on market conditions, but it will almost certainly be a fraction of the strike price itself.
Experts warn that in order to meet the UK's long term climate goals, additional sources of low-carbon energy will still be needed.

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Wednesday, September 13, 2017

One of world's largest marine parks created off coast of Easter Island



Map of the planned marine park (source The Guardian)

From The Guardian by Arthur Neslen

Rapa Nui protection area, about same size as Chilean mainland, will protect up to 142 species, including 27 threatened with extinction

One of the world’s largest marine protection areas has been created off the coast of Easter Island.

 Rapa Nui with the GeoGarage platform (NGA chart)

The 740,000 sq km Rapa Nui marine park is roughly the size of the Chilean mainland and will protect at least 142 endemic marine species, including 27 threatened with extinction.

An astonishing 77% of the Pacific Ocean’s fish abundance occurs here and recent expeditions discovered several new species previously unknown to science.

Apex predators found in the conservation zone include scalloped hammerhead sharks, minke, humpback and blue whales, and four species of sea turtle.

Easter Island’s waters are teeming with sea life, including 142 species found nowhere else on the planet and 10 endangered species.
See the animals and other underwater wonders that make this area so unique.

Matt Rand, the director of the Pew Bertarelli ocean legacy project, which campaigned for the park, said: “This marine reserve will have a huge global significance for the conservation of oceans and of indigenous people’s ways of life.
“The Rapa Nui have long suffered from the loss of timber, declining ecosystems and declining populations. Now they are experiencing a resurgence based on ensuring the health of the oceans.”

Plans for the marine park were first announced at a conference in 2015, at which the former US president Barack Obama declared his “special love for the ocean” in a video message.
The plans were confirmed in a speech by Chilean president Michelle Bachelet on Saturday.

The marine park’s creation was enabled by a 73% vote in favour of the conservation zone from Easter Island’s 3,000 Rapa Nui population in a referendum on 3 September, after five years of consultations.

Extractive industries and industrial fishing will be banned inside the reserve, but the Rapa Nui will be allowed to continue their traditional artisanal fishing on small boats, using hand lines with rocks for weights.

The indigenous people of Easter Island, the Rapa Nui, are connected to the ocean.
Women and men fish for their families, and gather shells to craft traditional jewelry and artwork.
But what happens when fish stocks decline and plastic from other countries washes up on the Easter Island coast?
The Rapa Nui formed Te Mau O Te Vaikava O Rapa Nui -the Mesa del Mar- an effort made up of prominent fishing, tourism, environmental, and cultural leaders, to determine the best ways to protect their ocean waters for future generations.

Ludovic Burns Tuki, the director of the Mesa del mar coalition of more than 20 Rapa Nui groups, said: “This is a historic moment – a great and beautiful moment for the Rapa Nui, for the world and for our oceans.
“We think this process can be an example for the creation of other marine reserves that we need to protect our oceans – with a respect for the human dimension.”


After the creation of a comparable marine protection area around the nearby Pitcairn Islands last year, proposals for a reserve in the Austral Islands’ waters could soon create a protected area of more than 2m sq km
 This would have a unifying potential for the Polynesian people, according to Burns Tuki.
“The ocean is very important to us as a source of food, but the Polynesians were great navigators and the ocean also represents our mother,” he said.
“It enables us to move with a double canoe between the different islands. It gives us everything.”

As global warming takes hold, some scientific papers suggest that marine reserves may also help mitigate climate change and provide a vital carbon sink.
The deep, clear and cool waters around Easter Island are also a resilient area for coral reefs.

Marcelo Mena, Chile’s environment minister, said: “This marine protected area adds to the legacy of President Bachelet and the 1.5m sq km of protected areas created by this government.”

The International Union for Conservation of Nature has called for 30% of the world’s oceans to be protected, but only about 1.6% has so far been covered by marine protection areas.

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Tuesday, September 12, 2017

Ship exhaust makes oceanic thunderstorms more intense

Lightning behind an aircraft carrier in the Strait of Malacca.
New research finds lightning strokes occurred nearly twice as often directly above heavily-trafficked shipping lanes in the Indian Ocean and the South China Sea year-round from 2005 through 2016. Credit: public domain.

From Phys 

Thunderstorms directly above two of the world's busiest shipping lanes are significantly more powerful than storms in areas of the ocean where ships don't travel, according to new research.

A new study mapping lightning around the globe finds lightning strokes occur nearly twice as often directly above heavily-trafficked shipping lanes in the Indian Ocean and the South China Sea than they do in areas of the ocean adjacent to shipping lanes that have similar climates.

The difference in lightning activity can't be explained by changes in the weather, according to the study's authors, who conclude that aerosol particles emitted in ship exhaust are changing how storm clouds form over the ocean.

The new study is the first to show ship exhaust can alter thunderstorm intensity.
The researchers conclude that particles from ship exhaust make cloud droplets smaller, lifting them higher in the atmosphere.
This creates more ice particles and leads to more lightning.

credit : NASA

The results provide some of the first evidence that humans are changing cloud formation on a nearly continual basis, rather than after a specific incident like a wildfire, according to the authors.
Cloud formation can affect rainfall patterns and alter climate by changing how much sunlight clouds reflect to space.
"It's one of the clearest examples of how humans are actually changing the intensity of storm processes on Earth through the emission of particulates from combustion," said Joel Thornton, an atmospheric scientist at the University of Washington in Seattle and lead author of the new study in Geophysical Research Letters, a journal of the American Geophysical Union.

"It is the first time we have, literally, a smoking gun, showing over pristine ocean areas that the lightning amount is more than doubling," said Daniel Rosenfeld, an atmospheric scientist at the Hebrew University of Jerusalem who was not connected to the study.
"The study shows, highly unambiguously, the relationship between anthropogenic emissions - in this case, from diesel engines - on deep convective clouds."

A map of ships crossing the Indian Ocean and surrounding seas during June 2012.
Most ships crossing the northern Indian Ocean follow a narrow, nearly straight track around 6 degrees North between Sri Lanka and the island of Sumatra.
East of Sumatra, ships travel southeast through the Strait of Malacca, rounding Singapore and extending northeast across the South China Sea.
Aerosol particle emissions in these shipping lanes are ten times or more greater than in other shipping lanes in the region, and are among the largest globally.
Credit: shipmap.org, an interactive map of commercial shipping movements, created by Kiln for University College London's Energy Institute.

All combustion engines emit exhaust, which contains microscopic particles of soot and compounds of nitrogen and sulfur.
These particles, known as aerosols, form the smog and haze typical of large cities.
They also act as cloud condensation nuclei - the seeds on which clouds form.
Water vapor condenses around aerosols in the atmosphere, creating droplets that make up clouds.

Cargo ships crossing oceans emit exhaust continuously and scientists can use ship exhaust to better understand how aerosols affect cloud formation.

In the new study, co-author Katrina Virts, an atmospheric scientist at NASA Marshall Space Flight Center in Huntsville, Alabama, was analyzing data from the World Wide Lightning Location Network, a network of sensors that locates lightning strokes all over the globe, when she noticed a nearly straight line of lightning strokes across the Indian Ocean.

Virts and her colleagues compared the lightning location data to maps of ships' exhaust plumes from a global database of ship emissions.
Looking at the locations of 1.5 billion lightning strokes from 2005 to 2016, the team found nearly twice as many lightning strokes on average over major routes ships take across the northern Indian Ocean, through the Strait of Malacca and into the South China Sea, compared to adjacent areas of the ocean that have similar climates.

More than $5 trillion of world trade passes through the South China Sea every year and nearly 100,000 ships pass through the Strait of Malacca alone.
Lightning is a measure of storm intensity, and the researchers detected the uptick in lightning at least as far back as 2005.

"All we had to do was make a map of where the lightning was enhanced and a map of where the ships are travelling and it was pretty obvious just from the co-location of both of those that the ships were somehow involved in enhancing lightning," Thornton said.

The top map shows annual average lightning density at a resolution of about 10 kilometers (6 miles), as recorded by the WWLLN, from 2005 to 2016.
The bottom map shows aerosol emissions from ships crossing routes in the Indian Ocean and South China sea from 2010.
Credit: Thornton et al/Geophysical Research Letters/AGU.

Forming cloud seeds

Water molecules need aerosols to condense into clouds.
Where the atmosphere has few aerosol particles - over the ocean, for instance - water molecules have fewer particles to condense around, so cloud droplets are large.

When more aerosols are added to the air, like from ship exhaust, water molecules have more particles to collect around.
More cloud droplets form, but they are smaller.
Being lighter, these smaller droplets travel higher into the atmosphere and more of them reach the freezing line, creating more ice, which creates more lightning.
Storm clouds become electrified when ice particles collide with each other and with unfrozen droplets in the cloud.
Lightning is the atmosphere's way of neutralizing that built-up electric charge.

Ships burn dirtier fuels in the open ocean away from port, spewing more aerosols and creating even more lightning, Thornton said.

"I think it's a really exciting study because it's the most solid evidence I've seen that aerosol emissions can affect deep convective clouds and intensify them and increase their electrification," said Steven Sherwood, an atmospheric scientist at the University of New South Wales in Sydney who was not connected to the study.
"We're emitting a lot of stuff into the atmosphere, including a lot of air pollution, particulate matter, and we don't know what it's doing to clouds," Sherwood said.
"That's been a huge uncertainty for a long time. This study doesn't resolve that, but it gives us a foot in the door to be able to test our understanding in a way that will move us a step closer to resolving some of those bigger questions about what some of the general impacts are of our emissions on clouds."

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Monday, September 11, 2017

Norway to spend $315M on world's first ship tunnel

The Norwegian Public Roads Administration believes floating underwater tunnels could be the key to shorter driving times in the country.
Norway is home to more than 1,100 fjords, the deep glacial water inlets that divide land masses. Getting over one means taking a ferry, and that can add hours to a car trip.
Because fjords can be up to a mile deep, building a bridge over the waterway or tunnel underneath is not very practical.
But Norwegian engineers think they can build a quicker way.
They want to float concrete tunnels up to 100 feet below the ocean’s surface.
This would allow ships to sail unobstructed by bridges.
Floating pontoons would hold the concrete tunnels in place.
Engineers hope the ambitious $25 billion project will be completed by 2035.

From CNN by Juliet Perry

Norway has unveiled plans to build the world's first ship tunnel by smashing through a solid rock peninsula.

The mile-long, 118-feet-wide tunnel will pass through the narrowest part of the Stad peninsula in western Norway, allowing freight and passenger ships to bypass the stormy, exposed Stadhavet Sea and avoid a highly treacherous part of the Scandinavian nation's coastline.
Norway has unveiled plans to build the world's first ship tunnel by smashing through a solid rock peninsula.



The mile-long, 118-feet-wide tunnel will pass through the narrowest part of the Stad peninsula in western Norway, allowing freight and passenger ships to bypass the stormy, exposed Stadhavet Sea and avoid a highly treacherous part of the Scandinavian nation's coastline.

The 118 feet wide, mile-long tunnel will carve through the Stad peninsula in western Norway
views from the GeoGarage platform (NHS charts)

"The Kråkenes lighthouse, just south of Stad, is the meteorological weather station with the most stormy days, which can be anything from 45 to 106 days per year," says the Norwegian Coastal Administration, which announced the project.

The very high waves coming from different directions create complex and perilous sailing conditions, even after the wind has died down.
"The combination of wind, currents and waves around this part of the coastline make this section a particularly demanding part of the Norwegian coast," the administration says.
It says it hopes the tunnel will improve safety and stop ships from having to wait for bad weather to pass.

Moldefjorden in Norway, where the southern tunnel entrance is planned.

The team anticipates it will take three to four years to build the tunnel and cost an estimated $315 million.
To create it engineers will have to blast out a huge eight million tons of rock.
Passages and canals for boats have been built elsewhere in the world, but this will be the first tunnel allowing cruise and freight ships that weigh up to 16,000 tons to pass through solid rock.

The team anticipates that up to five ships will be able to pass through the tunnel every hour.
If you're wondering what might happen if two ships come nose-to-nose, it's unlikely, because there will be traffic lights.
"We are going to follow the usual standard with red and white lights to show when it is safe to pass," the team says.
The tunnel is due to open in 2023.

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Norway NHS, a new layer in the GeoGarage platform

A new layer in the GeoGarage platform
© Kartverket / © Norwegian Mapping Authority 
see GeoGarage news

 Norwegian waters (Exclusive Economic Zone)
EEZs extend 200 kms from shore (unless it clashes with another EEZ).
Norway has the Svalbard Archipelago and Jan Mayen in the Arctic and Bouvet Island in the Arctic.
All their claims on them are due to their remote nature meaning that all it took was a few decades of Norwegian whalers spending time on those islands for much of the world too think: 'they can have those remote islands'.
As this map shows, that ownership does come with its perks. 

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Sunday, September 10, 2017

Water II

Water II from Morgan Maassen
An ode to the sea, which i revere most… Morgan Maassen
Water II is another fine example of his capacity to find a unique perspective of life at sea. 
Filmed in Hawaii, Tahiti, Maldives, Barbados, Indonesia, Mexico and California.

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Saturday, September 9, 2017

Comparing forecast models for Irma

courtesy of Google Crisis

From WeatherNation by Meteorologist Jeremy LaGoo

There’s a lot of talk of the uncertainty of exact track of Hurricane Irma as it nears a potential U.S.
landfall.
While we do our best as meteorologists to forecast an exact path of a given storm, there are countless factors that go into determining a given path.

NASA image of Irma's Towering Clouds
The MISR instrument on NASA’s Aqua satellite is comprised of nine cameras that view Earth at different angles. By combining two of MISR’s images of Hurricane Irma, you can get a 3-D look at the storm. You’ll need red-blue glasses to see the full effect.

The best forecasters of a potential path are at the National Hurricane Center.
Forecasting tropical systems is what these men and women do, so it only makes sense that they do it well.
This is where we get our forecast cone, and if you’re looking for a potential path– this is what you should trust

Keep in mind the cone is the possible path track.
It could still stray to the far eastern or western side of the forecast cone, drastically changing the impacts of the storm on the southeastern U.S.

The Models

For those that want something more, we can take a look at the individual models that go into the complete forecast.
  • GFS: Global Forecast System. 13 kilometer grid covering the entire planet factoring in numerous variables to predict weather out to 16 days.
  • NAM: North American Mesoscale Forecast System. 12 kilometer grid covering the North American continent, with the ability to run high-resolution forecasts.
  • EURO (ECMWF) European Center for Medium-Range Weather Forecasts. 9 kilometer grid and historically one of the most accurate models in tropical forecasting.
  • BAMS: Baron Services proprietary model used by WeatherNation. 15 kilometer forecast grid used in this model run.
 ECMWF model forecasts (courtesy of NYTimes)
often considered as more accurate than GFS model

Through Saturday morning these 4 models are less than 40 miles apart.
Sitting between Cuba and the Bahamas.


By Sunday morning the different forecast movements start to become more prominent.
Still no more than 100 miles apart, there is agreement on path– speed becomes the separator.


By Sunday afternoon both the EURO and the NAM make a southern Florida landfall while the GFS and BAMS stay off the east coast of Florida.


Sunday evening both the NAM and EURO move inland while the BAMS nears the Miami coastline.
The GFS remains offshore and speeds up with no land interaction.


Monday morning the models start spreading out.
Tens of miles turn to hundreds of miles as land makes its mark on the storm’s speed.
To be perfectly honest, the faster and farther offshore the better.


By Monday evening even more so.


 Your Best Bet

Prepare for the worst and hope for the best.
The most accurate forecast at any time will be the National Hurricane Center’s forecast cone.



It is updated every few hours throughout the day alone with advisories from around the region.

Hurricane Irma questions to National Hurricane Center acting Director Ed Rappaport

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Friday, September 8, 2017

The coral reef loss data hidden in old navigational charts



Example of nearshore coral loss near Key West, Florida.
(A) Excerpt of Guald’s 1774 nautical chart, with locations of coral indicated with black rectangles. The inset shows an enlarged image of two adjacent historical coral references. (B) Same area today, represented by Google Earth imagery overlaid on the compiled modern benthic habitat map. Black rectangles indicate areas of coral persistence; gray rectangles indicate coral loss.
Credit: Loren McClenachan

From AtlasObscura by Cara Giaimo

In the Florida Keys, researchers have found an important new way to estimate what’s been lost.

In 1774 and 1775, as the upper part of North America girded for war, a British surveyor named George Gauld was sailing around the Florida Keys, putting together maps.
The British Admiralty had sent him, and he made a point of marking, directly on his charts, wherever the natural landscape could affect naval movement.
“The Bank is full of Coral Patches and no Vessel ought to venture into less than 3 fathoms,” he wrote along the coast of one island in the South Keys.
He captioned blocks of water, carefully noting where “Coral” gave way to “Large Rocks,” or “Fine white Sand & Clay.”


Sepia tone: Gauld (1775), Upper Keys

Nearly two and a half centuries later, a different group of people are eager to know what he found. For a recent paper in Science Advances, a group of environmental scientists and historians teamed up to compare Gauld’s detailed maps to contemporary satellite surveys of coral reefs, in order to calculate how much reef cover has diminished over the past 250 years.
This long view, they think, could provide a more nuanced look at where coral is, was, and could be.

A detail of Gauld’s 1774 map, demonstrating his precise coral recording.
Loren McClenachan

Scientists hoping to get a handle on historic species populations have long turned to creative sources, many repurposed from more commercial endeavors.
Researchers working on the Census of Marine Life’s History of Marine Animal Populations project, for example, have looked at whaling records, fishery statistics, and even restaurant menus to estimate species counts.
Oyster fisheries have mapped out their beds since the late 19th century, and the same era’s nautical charts can help current geographers keep track of shoreline changes.

 Historical coral maps and zones and all historical coral observations
Color map: Gauld (1774), Lower Keys.

When Loren McClenachan came across Gauld’s maps nearly 10 years ago, in the archives of the United Kingdom Hydrographic Office, she knew they’d prove similarly useful.
“There was a lot of ecological information in them,” McClenachan, the study’s lead author and an environmental studies professor at Colby College, says.
“He wrote down where the turtles nested, and he described the mangroves.”
It did take her a while to figure out exactly how best to make use of them, though.
“I actually printed out a life-size replica and put it on my wall of my graduate student apartment at the time, and just sort of looked at it for a while.”

 Coral (Co nautical chart symbol) area in the Florida Keys
with the GeoGarage platform (NOAA chart)

Eventually, it clicked.
Gauld had been particularly careful about coral in the Keys, noting exactly where and how deep down the reefs were—the 18th century version of high-resolution data.
Meanwhile, a number of recent surveys, including the National Oceanic and Atmospheric Administration’s Unified Florida Coral Reef Tract Map and the United Nations’ Millennium Coral Reef Mapping Project, had done satellite sweeps of that same area.
“We figured out that we could compare [Gauld’s observations] to the satellite data,” McClenachan says.

 George Gauld's Plan of Part of the Florida Keys,
from Bahia Honda to Cayo Largo,
 courtesy of Heritage Charts

To do this, the researchers first translated Gauld’s various notes and markings into 143 geographically discrete “coral observations,” basically dots on a map that meant “coral was here.”
They then used a composite of three modern satellite surveys to check whether it was still present in that spot.
For over half the space surveyed, the answer was a resounding “no.”
“We estimate a 52 percent loss in the occurrence of corals in the Florida Keys over 240 years,” the researchers write.
“That is, just more than half of the historical coral observations are in locations where coral habitat does not exist today… Our analysis demonstrates that entire sections of the reef that were present before European settlement are now largely gone.”
They call these sections “ghost reefs.”
"An accurate chart of the Tortugas & Florida Keys or Martyrs surveyed..."
(scale : 1:135,000), bathymetrics shown by shading and soundings
published by William Faden (1790), and based on surveys conducted by George Gauld in the area from 1773-1775, who had been assigned by the British Admiralty to chart the waters off West Florida, where he was taken prisoner by Spanish forces during the siege of Pensacola, in 1781.
source : State Library of Florida, Florida Map Collection

When the researchers examined their results more closely, they also found that the coral vanished asymmetrically: the areas that lost the most reef cover tended to be closer to the shore.
Meanwhile, the farther out you went, the more coral stuck around.
In fact, “the alignment of historical and modern coral is nearly exact in some locations,” the researchers write, “suggesting little change to the overall reef structure.”

This also posits a diagnosis for the disappearance.
“We can’t pinpoint the reasons for decline—we just have these snapshots of then and now,” says McClenachan.
“But other lines of evidence make it seem likely that those [inshore corals] were lost due to human impacts,” such as dredging, shoreline hardening, and the rechanneling of the Everglades, which changed the salinity of Florida Bay.



A strong spatial gradient to coral loss in the Florida Keys.
(A) Study area.
(B). Modern and historical coral occurrences in the Florida Keys. The color of dots corresponds with the five delineated coral zones.
(C) Enlarged area demonstrates the loss of coral from Florida Bay (red).
(D) Enlarged area (Bahia Honda) demonstrates the loss of the nearshore patch reef (yellow) and the persistence of coral in the reef crest zone (blue).
For (C) and (D), corals that no longer remain are indicated with an X.
(E) Percent loss by zone. Bars represent the mean estimate of loss derived from three distance thresholds diameters (0.25, 0.5, and 0.75 km).
Error bars represent the SEs across those three estimates.

Coral today also live precarious lives: pollution is choking them out, careless boating is breaking them up, and climate change is warming and acidifying their habitats, killing off the algae that bring them to life.
(Hurricanes, like the one currently barreling toward the Keys, also don’t tend to do them any favors.)
If you’re used to reading coral studies, which regularly describe 75 percent declines in live coral over mere decades, a 52 percent loss over centuries might not seem so bad.

But McClenachan is quick to point out that this study is diagnosing a completely different category of disappearance: this 52 percent loss happened so completely, we no longer even look for coral in those places, because we don’t remember that it was ever there.
“It’s not a decline in live coral,” says McClenachan.
“It’s the entire loss of those reefs.”

To McClenachan, this recontextualization is part of what makes historical studies meaningful.
“If you don’t know about change, you’re not going to recognize it,” she says.
“When that happens over time, we have these lowered expectations for nature generally.”
It’s not just that we have a better idea of the destruction we’ve caused: expanding our historic imagination allows us to improve research in the present, and to think bigger for the future.

Currently, the Florida Keys are very invested in restoring coral reefs, re-seeding baby corals on existing reef sites and researching ways to make species more resilient as oceans change.
Knowing where the coral used to be could influence these plans.
“If you don’t know that it’s there it doesn’t make sense to look for it,” McClenachan says.
But if you know that George Gauld once kept his eyes peeled, you might start, too.

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Thursday, September 7, 2017

Hurricane Irma’s epic size is being fuelled by global warming

The map above shows sea surface temperatures in the Atlantic Ocean, Caribbean Sea, and Gulf of Mexico on September 5, 2017.
The data were compiled by Coral Reef Watch, which blends observations from the Suomi NPP, MTSAT, Meteosat, and GOES satellites and computer models.
The mid-point of the color scale is 27.8°C, a threshold that scientists generally believe to be warm enough to fuel a hurricane.
The yellow-to-red line on the map represents Irma’s track from September 3–6.

From New Scientist by Michael Le Page

It’s a monster.
As the eye of Hurricane Irma approached the tiny island of Barbuda this morning, wind speeds soared to 250 kph before the instrument broke.

On September 6, 2017, Hurricane Irma slammed into the Leeward Islands on its way toward Puerto Rico, Cuba, and the U.S. mainland.
As the category 5 storm approaches the Bahamas and Florida in the coming days, it will be passing over waters that are warmer than 30 degrees Celsius (86 degrees Fahrenheit)—hot enough to sustain a category 5 storm.
Warm oceans, along with low wind shear, are two key ingredients that fuel and sustain hurricanes.
The Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi NPP satellite captured a nighttime view of the storm at 1:35 a.m. local time (05:35 Universal Time) on September 6 as the eye was over the island of Barbuda.
The image was acquired by the VIIRS “day-night band,” which detects light in a range of wavelengths from green to near-infrared and uses filtering techniques to observe signals such as city lights, auroras, wildfires, and reflected moonlight.
In this case, the clouds were lit by the full Moon.
The image is a composite, showing storm imagery combined with VIIRS imagery of city lights.

At the time of writing, all contact with the island had been lost and it is unclear how the 1600 inhabitants have fared.
But already reports of severe destruction are coming in from other islands in Irma’s path.

The destruction could be extreme.
Hurricane Irma has the strongest winds of any hurricane to form in the open Atlantic, with sustained wind speeds of 295 kph.

The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite acquired the third image at 10:35 a.m. local time (14:35 Universal Time) on September 6, 2017.
By then, the storm had also hit Anguilla and was poised to strike the Virgin Islands.

It is also huge.
The strongest winds are limited to a relatively small area around its centre, but hurricane-force winds of 118 kph or more extend out 85 kilometres from its eye.

Irma could yet grow stronger and is going to graze or directly hit many densely-populated islands in the Caribbean before possibly making landfall in Florida on Sunday – but there is still a lot of uncertainty about its path and intensity this far ahead.

 NASA SPoRT Sea Surface Temperature product shows warm water along projected path of Hurricane Irma, favorable for maintaining strength.

Warmer waters

So why did Irma grow so strong?
Most likely because climate change is making Atlantic waters ever warmer.

Tropical cyclones are fuelled by warm surface waters of around 26°C or more.
They draw in moist air from all around them, and as it rises, the water vapour condenses out and releases latent heat, which drives further uplift. Irma’s clouds are 20 kilometres high.


However, as tropical cyclones grow stronger they churn up the ocean and bring deeper water to the surface.
Usually this deeper water is cooler, and cuts off the energy supply.

The strongest hurricanes, then, can only grow if warm waters extend down to depth of 50 or 100 metres – conditions normally only found in the Gulf or Caribbean.

In 1990, Hurricane Allen reached 305 kph winds, fuelled by these warmer waters.
In 2017’s warmer world, Irma began growing way out in the Atlantic, thanks to sea surface temperatures that were more than 1°C above average.

Bars depict number of named systems (yellow), hurricanes (red), and category 3 or greater (purple), 1850-2014

Stronger storms

Hurricane intensity depends on many other factors, too, though.
For instance, winds high in the atmosphere are often faster than those lower down, blowing away rising air and preventing hurricanes from forming, or growing very strong.
Low wind shear helped Irma grow into a perfect storm.

Computer models suggest global warming is likely to increase wind shear over the Atlantic, meaning there could no more or fewer hurricanes overall, but that storms grow stronger when they do form.

While tropical cyclones are currently ranked according to their wind speed, storm surges and flooding from high rainfall typically cause most of the damage, as we saw with Harvey.

The height of a storm surge depends not just on the strength of winds, but on their extent.
Hurricane Sandy’s winds were not that strong but the size of the storm piled up the huge storm surge that caused most of the damage in New York and elsewhere.

So strong winds don’t necessarily mean big damage.
The record is held by Hurricane Patricia in the eastern Pacific in 2015, with sustained winds of 345 kph.
Fortunately Patricia was small, weakened dramatically before landfall and struck a sparsely populated area.


Irma, ominously, is both big and intense, and could cause big storm surges in highly populated places. Barbuda recorded a storm surge of 2.4 metres.

The amount of rainfall dumped by hurricanes can also vary widely depending both on a storm’s intensity, local factor and how fast it moves.
Harvey produced huge amounts of rain because it barely moved for days.

Irma, thankfully, is moving faster – but its behaviour more than two or three days ahead remains highly uncertain.

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Wednesday, September 6, 2017

Irma: Atlantic's most powerful hurricane ever makes landfall in Caribbean

 This animation of NOAA's GOES East satellite imagery from Sept. 2 at 7:45 a.m. EDT (1145 UTC) to Sept. 5 ending at 7:15 a.m. CDT (1115 UTC) shows Hurricane Irma move west toward the Leeward Islands and strengthen to a Category 5 storm on Sept. 5.
Credit: NASA-NOAA GOES Project


Eye of hurricane passes over Barbuda, bringing down phone lines, as heavy rain and howling winds hit neighbouring island of Antigua

The most powerful Atlantic Ocean hurricane in recorded history has made its first landfall in the islands of the north-east Caribbean, following a path predicted to then rake Puerto Rico, the Dominican Republic, Haiti and Cuba before possibly heading for Florida over the weekend.

How strong is Hurricane Irma?
It’s registering on earthquake-detecting seismometers
 courtesy of NOAA

The eye of Hurricane Irma passed over Barbuda at about 1.47 am local time, the National Weather Service said.
Residents said over local radio that phone lines went down.
Heavy rain and howling winds hit the neighbouring island of Antigua, sending debris flying as people huddled in their homes or government shelters.

GOES-16 captured this infrared imagery of category 5 hurricane Irma bearing down on the Leeward Islands on September 5, 2017.
Note the gravity wave pattern emanating outward.
Irma was centered at 2 p.m. EDT on September 5, 2017, about 180 miles east of the Antigua, moving toward the west near 14 mph.
Reports from an Air Force Hurricane Hunter aircraft indicate that the maximum sustained winds have increased to near 185 mph with higher gusts.
On the forecast track, the extremely dangerous core of Irma is forecast to move over portions of the northern Leeward Islands tonight and early Wednesday.

Officials warned people to seek protection from Irma’s “onslaught” in a statement that closed with: “May God protect us all.”

In Barbuda, the storm ripped off the roof of the island’s police station, forcing officers to seek refuge in the nearby fire station and at the community centre that served as an official shelter.
The Category 5 storm also knocked out communication between islands.

The category 5 storm had maximum sustained winds of 185mph (295kph) by early Tuesday evening, according to the US National Hurricane Center (NHC) in Miami.


Irma strengthens into a category 5 hurricane with winds reaching up to 180 MPH and moving west at 14 MPH. It is the most powerful storm in 10 years.
Keep an eye on the forecast and hope for the best.
Category 5 hurricanes are rare and are capable of inflicting life-threatening winds, storm surges and rainfall.
Hurricane Harvey, which last week devastated Houston, was category 4.

Other islands in the path of the storm included the US and British Virgin Islands and Anguilla, a small, low-lying British island territory of about 15,000 people.

US president Donald Trump declared emergencies in Florida, Puerto Rico and the US Virgin Islands.

Warm water is fuel for hurricanes and Irma is over water that is one degree celsius (1.8F) warmer than normal.
The 26C (79F) water that hurricanes need goes about 250 feet deep (80m), said Jeff Masters, meteorology director of the private forecasting service Weather Underground.

Four other storms have had winds as strong in the overall Atlantic region but they were in the Caribbean Sea or the Gulf of Mexico, which are usually home to warmer waters that fuel cyclones. Hurricane Allen hit 190mph in 1980, while 2005’s Wilma, 1988’s Gilbert and a 1935 great Florida Key storm all had 185mph winds.

The storm’s eye was expected to pass about 50 miles (80km) from Puerto Rico late on Wednesday. Hurricane-force winds extended outward up to 60 miles (95km) from Irma’s centre and tropical storm-force winds extended outward up to 175 miles (280km).

credit : EarthNull

with tropical storm José close behind Irma
credit : Meteo France

The northern Leeward Islands were expected to see waves as high as 11 feet (3.3 metres), while the Turks and Caicos Islands and south-eastern Bahamas could see towering 20-foot (six-metre) waves later in the week, forecasters said.

Irma is expected to dump up to 18 inches (45cm) of rain in some areas when it hits land.
“These rainfall amounts may cause life-threatening flash floods and mudslides,” the NHC warned, calling the storm “potentially catastrophic” and urging that “preparations should be rushed to completion” in the region.

Schools and government offices in French overseas territory Guadeloupe have been ordered shut, while hospitals are stocking up on medicines, food and drinking water.
People living on shorelines will be moved to safety, authorities said.

The popular holiday destinations of Saint Barthelemy and St Maarten – a French territory and a French-Dutch split island respectively – are expected to be especially hard hit.
The Dutch defense minister said soldiers arrived in the Dutch part of St Maarten on Monday and two vessels, including one equipped with a helicopter, were in place to help.

Officials had on Monday ordered the evacuation of 11,000 people living in affected areas on both islands, which began in many neighbourhoods on Tuesday.
 
Winds and waves on W4D 2.0 mobile app

“This is not an opportunity to go outside and try to have fun with a hurricane,” US Virgin Islands governor Kenneth Mapp warned.
“It’s not time to get on a surfboard.”

The National Weather Service said Puerto Rico had not seen a hurricane of Irma’s magnitude since Hurricane San Felipe in 1928, which killed a total of 2,748 people in Guadeloupe, Puerto Rico and Florida.
“The dangerousness of this event is like nothing we’ve ever seen,” Puerto Rico governor Ricardo Rossello said.
“A lot of infrastructure won’t be able to withstand this kind of force.”
The director of the island’s power company has warned that storm damage could leave some areas without electricity for about a week and others for four to six months.
The utility’s infrastructure has deteriorated greatly during a decade-long recession, and Puerto Ricans experienced an island-wide outage last year.

 Irma view from the ISS

Government officials began evacuations and urged people to finalize all preparations as store shelves emptied out around Puerto Rico.
“The decisions that we make in the next couple of hours can make the difference between life and death,” Rossello said.
“This is an extremely dangerous storm.”
No directly storm-related deaths were reported by Tuesday evening but a 75-year-old man died in the central Puerto Rico mountain town of Orocovis after he fell from a ladder while preparing for the hurricane, police said.
The eye of the storm was expected to roar westward on a path taking it north of millions of people in Puerto Rico, the Dominican Republic, Haiti and Cuba, but meteorologists warned that it could still cause life-threatening storm surges, rains and mudslides.

The northern parts of the Dominican Republic and Haiti could see 10 inches (25cm) of rain, with as much as 20 inches in the south-east Bahamas and Turks and Caicos.

The storm seemed almost certain to hit the United States by early next week.
“You’d be hard pressed to find any model that doesn’t have some impact on Florida,” said University of Miami senior hurricane researcher Brian McNoldy.
In Florida, people also stocked up on drinking water and other supplies.
Governor Rick Scott activated 100 members of the Florida National Guard to be deployed across the state, and 7,000 National Guard members were to report for duty on Friday when the storm could be approaching the area.
On Monday, Scott declared a state of emergency in all of Florida’s 67 counties.
Officials in the Florida Keys geared up to get tourists and residents out of Irma’s path, and the mayor of Miami-Dade county said people should be prepared to evacuate Miami Beach and most of the county’s coastal areas.
Mayor Carlos Giménez said the voluntary evacuations could begin as soon as Wednesday evening. He activated the emergency operation centre and urged residents to have three days’ worth of food and water.

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