A green flash from the sun

Credit & Copyright: Andrew Penketh
(Eva Cassidy singing Ain't No Sunshine)

From NASA (Astronomy Picture Of the Day) & Cornell University

Green flash : many think it is just a myth.
Others think it is true but its cause isn't known.
Adventurers pride themselves on having seen it.

It's a green flash from the Sun.
The truth is the green flash does exist and its cause is well understood.
Just as the setting Sun disappears completely from view, a last glimmer appears startlingly green.
The effect is typically visible only from locations with a low, distant horizon, and lasts just a few seconds.
A green flash is also visible for a rising Sun, but takes better timing to spot.

Credit & Copyright: Juan José Manzano (Grupo de Observadores Astronómicos de Tenerife)

A dramatic green flash, as well as an even more rare blue flash, was caught in the above photograph recently observed during a sunset visible from Teide Observatory at Tenerife, Canary Islands, Spain.

Credit & Copyright: Pekka Parviainen (Polar Image, 1992)

The Sun itself does not turn partly green or blue -- the effect is caused by layers of the Earth's atmosphere acting like a prism.
The green flash is real but it is rarely seen, since it requires special conditions to be observed. The green flash is usually a band or vertical ray of green light just above the setting or rising sun, and can be green, violet, or blue.
To see it, you need a clear, flat horizon and a haze free sky.
An ocean works well - so do deserts.

"Rayon vert" Côte des Basques, Biarritz ©Sylvain Cazenave

The green flash is caused by rays of sunlight refracting (bending) in the atmosphere.
Because refraction depends on the wavelength (color) of the light, blue, violet and green light are refracted more than yellow, orange, and red light.
So at sunset, when the light has the most atmosphere to be bent by, the sun is surrounded by "shadows" of different colors, with the blue/violet/green shadows farther out.
The red, orange, and yellow shadows are abosrbed by the atmosphere, and the blue and violet shadows are scattered by the atmosphere, so the strongest shadow left is usually the green one.
This effect is only strong enough to see for a few seconds during sunrise and sunset, hence the "green flash."

To see the green flash again, you'll probably need to watch a lot of sunsets on clear days over the ocean.
It really is mostly just a matter of being in the right place at the right time.

Links :

• SanDiegoStateUniversity : an introduction to green flashes

IceDream: the Iceberg project

Turning icebergs into drinking water?

From DassaultSystems

Water is a vital resource in danger.
As the world starts to question the future of our blue gold, some sharp minds have come up with a slightly crazy idea: what if icebergs, gigantic freshwater reservoirs that they are, became the solution to the drinking-water shortage problem?
Using its advanced technology, Dassault Systèmes leads the investigation and simulates the feasibility of this unconventional project.

Freshwater Mountains

Potable water is a rare resource in many countries.
In the 21st century, nearly a billion people in the world still do not have access to clean water, while more than 2.5 billion have no water treatment system.
In light of these facts, researchers right across world are searching for solutions to produce potable water.
However, there are gigantic reservoirs of fresh water that have not been exploited: icebergs.

Unlike floe ice, which consists of frozen sea-water and is populated by wild animals, icebergs are drifting mountains of fresh water.
Calved from polar glaciers and continental icecaps, icebergs drift naturally in the ocean until they melt.
Each year, tens of thousands of icebergs are produced this way from glaciers, all destined to melt and be lost in the oceans’ salt waters.
And each year, the equivalent of a year’s consumption of potable water melts and disappears!

A Lifetime’s Dream

The idea of exploiting icebergs to produce fresh water is not new, and goes back to the 1950s with research projects by the US Army.
It gained momentum in the 1970s, notably under the influence of the famous French polar explorer Paul-Emile Victor, his friend and Arts et Métiers Engineer, Georges Mougin, and their meeting with the Saudi prince, Mohamed al-Faisal.
The first international convention on the use of icebergs was organized in Iowa in 1977, attended by 200 renowned participants, including engineers, scientists, military personnel, officials and journalists (see proceedings).

But the technical obstacles are complex; experimentation required astronomical budgets and the technology did not yet exist.
In the following years, the excitement died down and the scientists turned towards other, more realistic, less controversial and less costly projects.

A New Breath of Life

At the time, the idea of towing an iceberg seemed unrealistic.
But in the last 40 years, there has been considerable technical progress and our knowledge of icebergs has greatly improved.
Could Georges Mougin’s project be reborn?

His whole life, Georges Mougin has honed his theory of towing icebergs and has thought about capturing a tabular iceberg.
He then studied the best way to slow its melting and he imagined an unheard-of invention, a skirt made from non-woven geotextile strips.
Finally, he had to come up with the best solution for towing the iceberg with a single, high-powered tugboat, while using as little energy as possible: using following currents.

In 2009, he decided to knock at the door of Dassault Systèmes.
Indeed, he had just watched a showing of the 3D interactive documentary “Khufu Revealed” (a VirTools project) at the Geode.
Then, Georges Mougin thought of all this technology for his project: virtual worlds and 3D simulations would allow his various theories on iceberg-towing to be tested virtually to see whether his idea would be feasible.

Born in St Malo, Georges Mougin grew up in cod-fishing world of Newfoundland.
His father ran a local workshop that maintained the fishing boats.
In 1947, a few years after leaving Arts et Métiers, with the help of a Danish naval architect, he coordinated the work of transforming a US surplus ship into a polar vessel that became the “Commandant Charcot”.
This was when he met Paul-Emile Victor, and was the start of a 50-year friendship and of his fascination with the Antarctic.
Together with the Saudi prince Mohammed al-Faisal, he founded the ITI Company (Iceberg Transport International), which from 1975 to 1981 established the conditions of feasibility of transferring and exploiting tabular icebergs from the Antarctic, but had to give up the project in the face of numerous obstacles.
Since 2003, taking account of the creation of oceanic forecasting services, and the availability of maritime resources developed for off-shore oil drilling, Georges Mougin endeavored to reactivate this project to exploit icebergs.

Links :

• TheGuardian : The iceman cometh
• IceDream FAQ
• Time : Towing iceberg (1977) / NewScientist (1977)
  
• ISOPE 2009 : Iceberg Freshwater Sustainable Transportation, a New Approach
• YouTube : MD Group AS, Ice Management operations in the northern areas.
  

FAA approves iPads for pilots' electronic charts

The Federal Aviation Administration is allowing a private-jet company
to use iPads as an approved alternative to paper charts

From Wired

From the earliest days of aviation, pilots have relied upon paper maps to help find their way.
Even in an era of GPS and advanced avionics, you still see pilots lugging around 20 pounds or more of charts.
But those days are numbered, because maps are giving way to iPads.

The Federal Aviation Administration is allowing charter company Executive Jet Management to use Apple's tablet as an approved alternative to paper charts.
The authorization follows three months of rigorous testing and evaluation of the iPad and Mobile TC, a map app developed by aviation chartmaker Jeppesen (a Boeing company).

The latest decision applies only to Executive Jet Management, but it has implications for all of aviation.
By allowing the company's pilots to use the Apple iPad as a primary source of information, the FAA is acknowledging the potential for consumer tablets to become avionics instruments.


The iPad has been popular with pilots of all types since its introduction last year.
But until now, it could not be used in place of traditional paper charts or FAA-approved devices such as more expensive, purpose-built electronic flight bags.
The iPad was OK for reference, but not as a pilot's sole source of information.
The new FAA authorization changes all that.

To receive FAA authorization, Jeppesen and Executive Jet Management went through a rigorous approval process.
It included rapid-decompression testing from a simulated altitude of 51,000 feet and ensuring the tablet will not interfere with critical navigation or electronic equipment.
Executive Jet tested the iPad and Mobile TC in 10 aircraft flown by 55 pilots during 250 flights.
The first thought many pilots, not to mention passengers, may have is: What happens if the iPad or the app crashes?

Jeff Buhl, Jeppesen's product manager for the Mobile TC app, says the Apple iOS operating system and the app proved "extremely stable" during testing.
In the "unlikely" event of a software crash, he says, it takes but a moment to get them running again.
"The recovery time for an application crashing or the OS crashing is extremely rapid," Buhl says.
During the evaluation period with the FAA, the production app did not crash.
But even if it did, Buhl says it's ready to go again "in 4-6 seconds from re-launch to previous state."

The FAA says each individual operator -- in this case Executive Jet Management -- must develop specific procedures for dealing with system or software crashes and other issues.
Under the authorization, Executive Jet Management will require a second approved electronic device, which most likely will be another iPad, in the cockpit.

Although this authorization applies to just one company, it is a milestone for all operators, including major airlines, because it opens the door for them to embrace the iPad.
Though any company wishing to follow Executive Jet's lead will have to endure equally rigorous scrutiny by the FAA.

Agency spokesman Les Dorr says the process is no different from what is required for any other electronic device used to display navigation information.
"As far as the iPad is concerned, we do that on a case-by-case basis when an airline applies to be able to use it," Dorr says.

The FAA is already seeing more requests to use the iPad in the cockpit.
Alaska Airlines began testing the iPad back in November and there are about 100 pilots currently evaluating the device according to spokeswoman Marianne Lindsey.
She says in addition to the convenience, there is a practical weight-saving aspect to using the iPad as well, "it's replaced about 25 pounds of manuals and charts."

Jeppesen's director of portfolio management, Tim Huegel, says several carriers are looking into using the iPad and TC Mobile, and with the FAA granting one approval, it should become increasingly easy for others to follow Executive Jet's lead.
"We'll be able to reuse a lot of the documentation and the lessons learned working with Executive Jet Management to help our commercial customers as they now begin to pursue FAA authorization," he says.

The charts available with Mobile TC include charts for visual flight rules and for instrument flight rules, which are more commonly used by commercial operators.
The app only shows an electronic version of the paper charts Jeppesen has been producing for years, but Huegel says future versions could incorporate the iPad's GPS capability.

He sees a day when tablets provide "door-to-door management" of a pilot's information, from crew scheduling to weather information to navigation charts.

Links :

• Flightglobal : FAA approval of iPad EFB for Executive Jet paves way for industry
• AOPA : How will the iPad change the GA cockpit?
  

Scripps mapping subsea mountains taller than Mt. Whitney

Seafloor in the South Atlantic Ocean.
The low resolution map is derived from satellite altimetry while the high resolution swath was collected by Melville
during their transit across the South Atlantic from Cape Town, South Africa to Punta Arenas, Chile.

From SignonSanDiego

Mount Whitney rises 14,494 feet high in California’s majestic Sierra Nevada, making it the highest summit in the lower 48 states.
It also means Whitney is shorter than some of the undersea mountains — or seamounts — that are now being charted by the Melville, a research vessel out of the Scripps Institution of Oceanography.

SIO officials say scientists aboard the Melville are finding seamounts as tall as 14,700 feet on a mapping mission underway in the South Atlantic.
One of the seamounts has a diameter of 87 miles, roughly the distance between San Diego and Long Beach.

“Only about seven percent of the seafloor has been mapped by ship, so there are a lot of uncharted seamounts around the world,” said David Sandwell, an SIO geophysicist who is helping guide scientists aboard the Melville from his office in La Jolla.

“It’s important to study them. We need to understand the geology of the ocean floor.”

Sandwell says some of the seamounts are inactive volcanoes that can affect the path of ocean currents which, in turn, can affect weather and climate.
The seamounts also are gathering spots for a diverse collection of marine species, including some types of commercially harvested fish.

Locating and charting the seamounts is tricky business.
Scientists use satellite radar to study the ocean’s surface.
Those images reveal the rough location of subsea volcanoes and seamounts.
But then scientists have to go to sea and use sophisticated sonar to map the upper reaches of the mountains -- which is what researchers on Melville have been doing as they’ve explored a region 1,200 miles southwest of Cape Town, South Africa.

Sandwell said that the captain of the Melville, Chris Curl, has to approach the seamounts carefully because the peaks can rise close to the surface, posing a hazard to navigation.
In 2005, the nuclear-powered submarine USS San Francisco struck an uncharted seamount while operating 500 feet deep off Guam (see article).
The collision killed one crew member and injured 23 others.

J.J. Becker, a geophysicst aboard Melville, said in a statement, “These particular seamounts are so steep that it was nerve-wracking to go from 9,840 feet of water to less than 1,640 feet in 15 or 20 minutes!”

Scientists said charting the seamonts won’t be completed any time soon.

“There are many areas the size of New Jersey for which we have no information,” Sandwell said.
“That’s worse than the coverage we have for Venus and the far side of our own moon.”

The public can follow the movement and work activity on R/V Melville online.

Links :

• SCRIPPS : Scripps research vessel discovering mammoth undersea mountains / Scripps Dives into the Ocean with Google Earth
• Seamounts online / Global seamounts database
• MGDS : Global Multi-Resolution Topography data portal
  

Cargill to start flying kites across the ocean: SkySails will reduce carbon emissions of shipping vessels

From Treehugger

Food and agriculture giant Cargill will soon start using giant kites on its shipping vessels to generate propulsion—and reduce fuel consumption by up to 35 percent.

The kites, a product of Germany-based SkySails GmbH & Co., are 320 square meters in size, fly ahead of the vessels at a height of 100 to 420 meters, and are computer-controlled by an automatic pod to maximize wind benefits.
The kites will save up to ten tons of fuel a day.

Not that the kites themselves are new: we already knew they outperform regular sailboats and that they've been successful on trans-Atlantic freight trips.
And of course, the one positive move doesn't undo some of the more questionable, if not downright evil, practices we've known Cargill for in the past.

But it's worth recognizing nonetheless.
Cargill doesn't own or operate ships, but has identified a company that will test the technology, which will be installed in December.
Cargill and SkySails are planning to have it fully operational in early 2012.

According to Cargill, its ocean transportation business ships more than 185 million tons of agricultural, energy, and industrial commodities annually.
Cargill's G.J. van den Akker said, "As one of the world's largest charterers of dry bulk freight, we take this commitment extremely seriously. In addition to lowering greenhouse gas emissions, the SkySails technology aims to significantly reduce fuel consumption and costs."

"We are delighted that Cargill is the first company to embrace our technology on a vessel this large as part of its commitment to help reduce greenhouse gas emissions in the shipping industry," said Stephan Wrage, managing director of SkySails.
"We are excited that our technology will shortly be used on a handysize vessel for the first time and see great potential to incorporate it on larger ships in the future."

According to a UN study, up to 100 million tons of carbon dioxide emissions could be eliminated every year if the SkySails technology were adopted by the world merchant fleet on a large scale.

Links :

• GEreports : Go fly a kite! GE teams with shipper to cut fuel costs
• ForumfortheFuture : Sustainable Shipping Initiative (SSI)
• YouTube : SkySails bring windpower to container ships / Beluga SkySail