465 boats... 66.5 Nm of course... peaks at 60 knots...
A Dantean edition of the Bol d'Or Mirabaud, the world's largest closed basin regatta
Links :
- Voiles et Voiliers : Images / Images2
- YouTube : Rafica monhull
Saturday, June 22, 2019
Mirabaud 2019 'Bol d'Or' sailing race : Morpho dismasting in a storm
Links :
Friday, June 21, 2019
AIS gets an upgrade
AIS data at work in a VTS center (file image courtesy Saab)
From Maritime Executive
AIS has made it far easier for navigators to identify vessel movements for collision avoidance, and it has made shipping far more transparent by enabling worldwide vessel tracking services.
The industry has grown since AIS rolled out in the early 2000s, and a much-needed update is on the way: VHF Data Exchange System, or VDES, which will incorporate AIS plus several valuable new functions.
VDE system concept and available communication links
VDES will operate in VHF frequencies adjacent to the existing AIS channel, and will use a different network protocol to increase its throughput capacity.
This will boost the system's capacity for ship-to-ship, ship-to-shore, ship-to-satellite and virtual ATON applications, eliminating the network limitations that affect high-traffic areas today.
It will have up to 30 times more bandwidth, which will also give it more capacity for sharing weather forecasts, alerts and other data packets that are a bit too large for AIS.
Vessel traffic along Western Europe given by ExactEarth.
a Expected
coverage for satellite VDE beyond the coverage of the coastal stations.
b
Expected traffic density overall
VDES is also expected to increase navigation data security by adding access control and authentication features for AIS radio traffic.
Since it is authenticated, it could be used to provide warning in the event of GNSS jamming and spoofing, according to Johan Lindborg, project manager for marine and defense tech company Saab.
Saab is already working on type approval for a VDES-capable AIS base station, with an upgrade path for full VDES available by 2021 - about the same time that the new protocol is expected to enter into operation.
VDES may also incorporate a dedicated channel for two-way VHF ship-to-satellite communications, which could be used to share ice routes, weather updates or GNSS status reports, among other uses.
The International Telecommunication Union will consider setting aside a channel for this purpose at a meeting in November.
The new protocol could also provide the backbone for a backup positioning system in the event of GNSS spoofing or jamming.
Researchers from the German Aerospace Center are now testing a new terrestrial navigation system, R-Mode, which leverages existing radionavigation transciever stations on shore (DGNSS reference stations and AIS base stations) to transmit timed positioning signals.
Since the cost of implementation is low relative to a full-fledged, purpose-built system like eLoran, R-Mode is a promising way to bring resiliency to e-navigation, according to IALA.
Links :
- Springer : VHF Data Exchange System (VDES): an enabling technology for maritime communications
- Maritime Executive : Time to Take Another Look at Satellite AIS Data / Buyer Beware: Hefty Fines for Noncompliant AIS Devices
- Workboat : FCC issues advisory on non-compliant AIS equipment
- Powerboat : Simrad announces the first VHF Radio with AIS transmit/receive capability
- Lloyds : ‘Dark ship’ detection exposes sanction-busting ships
Thursday, June 20, 2019
Massive 8,000-mile 'dead zone' could be one of the gulf's largest
Seen from above (Photograph by Phil Degginger, NASA Landsat ), the Mississippi River carries sediment into the Gulf of Mexico.
That sediment often contains pollutants from fertilizers that cause a spike in algal blooms.
From National GeoGraphic by Sarah Gibbons
Record-breaking Midwest rainfall washed tons of fertilizer and sewage water out to sea, contributing to a devastatingly large patch of polluted water, scientists say.
Just off the coast of Louisiana and Texas where the Mississippi River empties, the ocean is dying.
The cyclical event known as the dead zone occurs every year, but scientists predict that this year's could be one of the largest in recorded history.
A satellite image of the Gulf of Mexico showing sediment flowing into it from the Mississippi River.
NASA Earth Observatory
NASA Earth Observatory
Annual spring rains wash the nutrients used in fertilizers and sewage into the Mississippi.
That fresh water, less dense than ocean water, sits on top of the ocean, preventing oxygen from mixing through the water column.
Eventually those freshwater nutrients can spur a burst of algal growth, which consumes oxygen as the plants decompose.
The resulting patch of low-oxygen waters leads to a condition called hypoxia, where animals in the area suffocate and die.
Scientists estimate that this year the dead zone in the Gulf of Mexico will spread for just over or just under8,000 square miles across the continental shelf situated off the coast.
Choking an ecosystem
“When the oxygen is below two parts per million, any shrimp, crabs, and fish that can swim away, will swim away,” says Louisiana State University ocean ecologist Nancy Rabalais.
“The animals in the sediment [that can't swim away] can be close to annihilated.”
Animals like shrimp will often search for more oxygen in shallower waters closer to the shore.
Shrimp subjected to hypoxic waters are smaller, their growth stunted by pollution.
One study published in 2017 noted how the dead zone affects Gulf Coast shrimpers by driving down the price of shrimp and reducing profit for local businesses.
Dead zones are not unique to the Gulf of the Mexico, though the gulf's is estimated to be the world's second largest.
In the world's largest dead zone, in the Baltic Sea, low oxygen devastated fisheries, and most marine animals can no longer survive there.
Off the West Coast of the United States, California and Oregon crab and oyster industries have reported profit losses since the early 21st century, saying the annual wave of low oxygen ocean water has destroyed many of the animals they normally fish from the sediment.
Hypoxic zones are areas in the ocean of such low oxygen concentration that animal life suffocates and dies, and as a result are sometimes called "dead zones."
One of the largest dead zones forms in the Gulf of Mexico every spring.
This data visualization discusses the causes of hypoxia in the Gulf of Mexico.
Credit: National Oceanic and Atmospheric Administration (NOAA) 2009
Dead zone causes
Rabalais says she's not surprised that this year's dead zone will be particularly large.
Much of the Midwest saw unprecedented rainfall this spring, leading to a large increase in the amount of runoff washing into the sea.
Many farmers were so affected by the intense rains that they were unable to plant crops like corn and soybean, meaning all the nitrogen and phosphorus-rich fertilizer they had spread washed into the Mississippi.
Scientists are predicting that a warming climate could lead to more extreme rainfall in the region and ultimately make it more difficult to control fertilizer runoff.
“The best way to solve the issue is to limit the nutrients at their source,” says Rabalais.
“Once they're in the river, there's no good way to reduce them.”
Eugene Turner, also from Louisiana State University, worked with Rabalais on predicting the size of the dead zone.
He says better management practices could reduce the size, and suggested maintaining soil health by rotating crops, using less fertilizer, and using crop covers to keep soil in place.
David Scheurer is a scientist from the National Oceanic and Atmospheric Administration who studies dead zones.
He notes that it's difficult to attribute a larger dead zone to just one practice like agricultural runoff, but notes that it plays a significant role in the zone’s formation.
Sewage water and weather also impact the size of the dead zone.
Senior director of congressional relations at the American Farm Bureau Federation Don Parrish says farmers are already adopting practices to reduce nutrient runoff.
Precision farming and artificial intelligence are both helping farmers reduce the amount of fertilizer they need to use on crops.
High costs and a steep learning curve are making it difficult for the sustainable technologies to be adopted by all farmers, Parrish adds.
“Scientifically we can reduce the size, but whether you can get there politically, that's still a work in progress,” he says.
Climate change and dead zones
Scientists are now worried that warming waters in the Gulf of Mexico could increase rates of hypoxia.
“That is a long-term concern,” says Scheurer.
“If the climate does change in that region, there is a fair amount of evidence suggesting you would expect things to get worse.”
Simply put, warm water is less capable of carrying oxygen, and a study published last year noted stretches of low-oxygen water thousands of miles across the ocean.
Climate change is also expected to cause more intense precipitation and flooding in the Midwest, which will contribute to the amount of chemical fertilizer washed into the ocean.
Both Scheurer and Rabalais, however, say it's too early to say that the gulf's dead zone is already being made worse by climate change.
Rabalais says she expects the dead zone to worsen in the future, further harming the ecosystem.
“You of course remember the BP oil spill?” she asks.
“This is a slow drip kind of change in the system thats been happening over decades, but it's just as consequential.”
Links :
- Phys : There's a giant dead zone in the Gulf of Mexico thanks in large part to ...
- NPR : The Gulf Of Mexico's Expanding Dead Zone
- Gizmodo : The Gulf of Mexico's 'Dead Zone' Could Balloon to Over 8000 Square ..
- TED : The "dead zone" of the Gulf of Mexico
- NASA video : The Ocean's Green Machines
- GIS user : Very large dead zone forecast for the Gulf of Mexico
- The National : World's largest marine dead zone may reach UAE's shores
- GeoGarage blog : Bigger dead zone ever forecast in Gulf of Mexico / Oxygen-starved 'dead zones' with no marine life up ... / Oceans suffocating as huge dead zones quadruple ... / Artificial ocean dead zones help predict real thing / More progress in reopening of Gulf waters for fishing
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