Hurricanes on the move! Tropical storms shift toward poles

Tropical storm tracks between 1985 and 2005. (NASA)
More hurricanes moving to populated places, say scientists

From LiveScience by Becky Oskin

Hurricanes and typhoons are migrating from the tropics toward the North and South poles, a new study finds.

In the past 30 years, the total number of storms has remained about the same in the tropics, said lead study author Jim Kossin, a climate scientist with the National Oceanic and Atmospheric Administration's National Climatic Data Center.

What are hurricanes, typhoons and tropical cyclones? How do they form?

(MetOffice)

What has changed, however, is the number of successful storm births.
The new study found that tropical storms don't peak in the tropics as often as they did 30 years ago. Instead, more and more storms are reaching their maximum strength at higher latitudes, according to the report, published May 14th, in the journal Nature.

"The tropics are becoming less hospitable for tropical cyclones, and the higher latitudes are becoming less hostile," Kossin told Live Science's Our Amazing Planet.
Tropical cyclones (the broad name for hurricanes, typhoons and tropical storms) spin up over and over in the same regions — a group of storm nurseries ringing the tropics — because of favorable wind patterns and ocean temperatures.

 Typhoon Francisco and Super Typhoon Lekima on October 23, 2013

as they tracked northwestward toward China and Japan.

(Credit: Tim Olander and Rick Kohrs, SSEC/CIMSS/UW-Madison,

based on Japan Meteorological Agency data.)

Storm nurseries stir

Kossin and his co-authors think a simultaneous expansion in the planet's tropical belts underlies the overall change in storm intensity.
The tropics have widened by about a degree in latitude each decade since 1979, according to separate studies by other research groups.
The expansion also could have pushed the ideal storm-forming regions toward the North and South poles.

 Diagram of tropical air circulation, including the Hadley Cell.

"There is certainly compelling evidence the two are linked, but we're not sure exactly how — that's what we want to find out," Kossin said.
"This is a link that needs to be examined."
The expansion of the tropics has been linked to global warming and ozone loss.
But scientists still hotly debate the impact of global warming on hurricanes.
Storms could become more or less frequent, more intense or a combination of these changes, researchers say.
"This study establishes another link between global climate change and global tropical cyclone activity," said Hamish Ramsay, a climate scientist at Monash University in Australia who was not involved in the research.
"It also raises a number of new questions, though."
The poleward trek doesn't necessarily mean that ferocious storms will be hitting the Atlantic coastline more often.
As climate changes, fluctuating wind patterns could cause tropical storms to move toward or away from coastlines, for instance.
And the study didn't examine landfall, where storms do the most damage.
Another confounding factor: The Atlantic Ocean storm nursery did not move north in the past 30 years, the researchers reported.
Kossin said he suspects that regional effects in the Atlantic, such as aerosol pollution (tiny airborne particles), could be offsetting the overall tropical widening.

 Color-enhanced infrared satellite image of Typhoon Usagi as it moved northwestward toward Hong Kong while explosively intensifying to a Category-5 storm.

Image: NOAA/Cooperative Institute for meteorological satellite studies, University of Wisconsin-Madison

Heading north

By tracking where tropical cyclones hit at their strongest point, called peak intensity, the scientists discovered that storms are heading north and south.
This method avoids problems with comparing storms between different oceans, Kossin said. Determining peak intensity is relatively consistent among different storm-tracking centers, he said. Other criteria, such as when a tropical storm tips into hurricane strength, can vary from center to center, making comparisons difficult.

The push poleward averaged about 33 miles (53 kilometers) per decade in the Northern Hemisphere and 38 miles (61 km) per decade in the Southern Hemisphere — a total shift of about 1 degree latitude per decade.
But some oceans saw a greater change than others.
The biggest moves occurred in the Pacific Ocean and South Indian Ocean, but the peak intensity of Atlantic hurricanes and storms in the North Indian Ocean showed almost no change.

Kossin said the researchers don't yet know why some oceans nurtured higher-latitude storms and others saw little change.

Links :

• BBC : Tropical storms migrate toward poles

NZ Linz update in the Marine GeoGarage

As our public viewer is not yet available
(currently under construction, upgrading to Google Maps API v3 as v2 is officially no more supported),
this info is primarily intended to our iPhone/iPad universal mobile application users
(Marine NZ on the App Store) 
and our B2B customers which use our nautical charts layers
in their own webmapping applications through our GeoGarage API.  

3 charts have been updated in the Marine GeoGarage

(Linz April update published May 2, 2014) 

• NZ56 Table Cape to Blackhead Point
• NZ561 Approaches to Napier
• NZ4315 Approaches to Onehunga

Today NZ Linz charts (180 charts / 313 including sub-charts) are displayed in the Marine GeoGarage.

Note :  LINZ produces official nautical charts to aid safe navigation in New Zealand waters and certain areas of Antarctica and the South-West Pacific.

Using charts safely involves keeping them up-to-date using Notices to Mariners
Reporting a Hazard to Navigation - H Note :
Mariners are requested to advise the New Zealand Hydrographic Authority at LINZ of the discovery of new or suspected dangers to navigation, or shortcomings in charts or publications.

Could this shipwreck be Christopher Columbus' Santa Maria?

This image of a Santa Maria replica was taken around 1904.
Detroit Publishing Co./Library of Congress

From CNET by Amanda Kooser

A wreck off the coast of Haiti has been tentatively identified by underwater explorer Barry Clifford as the remains of one of Columbus' long-lost vessels.

It's a mystery over 500 years in the making.
We've all heard the poetic phrase, "In 1492, Columbus sailed the ocean blue."
He traveled with three ships, the Niña, the Pinta, and the Santa Maria.
The third may have finally been found on the ocean floor off the coast of Haiti.
If the discovery is confirmed, it could be a major archeological event.

A hand-drawn map by Christopher Columbus shows the northern coast of Española (Hispaniola), where his flagship, the Santa Maria, sank in 1492.
Columbus wrote that the wreck was 1½ leagues from La Navidad, the fortified encampment he founded in what is now Haiti after the loss of the Santa Maria, Clifford said.
The wreck sits the equivalent of 1½ leagues from the site suspected to be La Navidad.


The wreck's resting place lies near breaking waves, as Columbus reported.
It was in a sandy spot, as implied in Columbus' journal.
At the site, the team found a field of stones 40 feet long and 20 feet wide.
That corresponds to the likely dimensions of the Santa Maria, which would've carried ballast stones in her hold.

Barry Clifford is an ocean explorer especially known for his discovery of the pirate shipwreck Wydah.
He has been on the hunt for the Santa Maria for years.
The shipwreck he believes to be that long-lost vessel was actually first found and photographed back in 2003.

A diver measures a cannon during a 2003 expedition off Haiti.
At the time of the discovery, archaeologists ruled out a connection to Christopher Columbus's ship, the Santa Maria.
It wasn't until 2012, after extensive research, that an investigator realized it could be connected.
“All the geographical, underwater topography and archaeological evidence strongly suggests that this wreck is Columbus’ famous flagship, the Santa Maria,” said the leader of a recent reconnaissance expedition to the site, one of America’s top underwater archaeological investigators, Barry Clifford.
(see video on History website)

A fresh look at the photos and the site led Clifford to the new conclusion.

Shipwreck found at 4.7 Nm offshore from Cap Haïtien in only about 10 feet of water depth

(NGA chart in the B2B GeoGarage viewer)

Clifford has quite a few reasons to believe he's found the right ship.
Columbus left details in his diary about the location of the sinking, which happened near Haiti on Christmas Day in 1492.

 Extract from Colombus journal

That description matches the shipwreck's whereabouts.
The size of the shipwreck is also consistent with the dimensions of the Santa Maria.
A cannon discovered with the wreck in 2003 was recently reevaluated and identified as matching one that would have been on board.
Unfortunately, that cannon was plundered from the site in the intervening years.
The photographic evidence is all that remains.
One reason why the ship was not identified as possibly being the Santa Maria back in 2003 has to do with the cannon.
Clifford told CNN the weapon was originally "misdiagnosed" by archeologists at the time.
Further research led him to an epiphany that the cannon could indeed be correct for the Santa Maria.

 This map shows Christopher Colombus route around the West Indies.

Remains which are though to belong to the Santa Maria were found off the Haiti's northern coast

"I am confident that a full excavation of the wreck will yield the first ever detailed marine archaeological evidence of Columbus' discovery of America," Clifford told The Independent.
He hopes the wreck will be at least partially recoverable so it could go on exhibit in Haiti.
Clifford's explorations have been aided by technology.
Besides underwater photography, his team uses sonar equipment and marine magnetometers to scour the ocean bottom in search of historically important shipwrecks.
The magnetometer is a device that measures changes in the magnetic field along the seabed.
It can help detect submerged materials, like iron used in ships and cannons.

If the ship is the Santa Maria, it would be the oldest known European shipwreck in the so-called New World and a find of major archaeological significance.

But scientists say it's far too early to make any such declaration especially since there is likely to be very little left of the vessel.
"The evidence, as you can imagine, after more than 500 years is not going to be very much because of time and the environment that the site is in," said Roger C. Smith, the State Underwater Archaeologist for Florida.

"It's going to require some careful archaeology."
Smith, who has searched for wrecks of Columbus' ships in Haiti, the Dominican Republic, Jamaica and Panama, said it's possible the ship found by Clifford is the Santa Maria, but he noted that there was at least one wreck in that area that was once mistakenly thought to be the ship but turned out to be a much later vessel.
Kevin Crisman, director of the Center for Maritime Archaeology and Conservation at Texas A&M University, said many Spanish ships sank off Haiti and the Dominican Republic, and it will be difficult to confirm that this is the Santa Maria.
"Anything is possible in this world, but I would like to see all the evidence, and so far this is not too promising," Crisman said.

The rest of Columbus' famous trio of ships also met mysterious fates.
The Pinta and Niña both made it back to Spain after Columbus' original transatlantic voyage, but what became of the Pinta after that is not known.
The Niña was last noted to have been traveling along the Pearl Coast near Venezuela in 1501 on a trading voyage.

Whatever your thoughts on Columbus and his mixed legacy, the discovery of one of his ships would be a huge historical find that could shed more light on a fascinating era of exploration.

Links :

• History : 10 Things You May Not Know About Christopher Columbus
• YouTube : Discovery Channel,  Barry Clifford - La búsqueda de la Santa María de Cristobal Colon I / II / III / IV
• The lost of Santa Maria by Arthur Davies (Discovery of America) / Colombus Journal
• Journal de bord de Christophe Colomb (in French)

Nereus deep sea sub 'implodes' 10km-down

HROV Nereus Animation from Woods Hole Oceanographic Inst.

From a functional point of view, Nereus kind of operates in two different modes.

It can operate as an autonomous vehicle, which means it is able to survey the sea floor with very little direct human control.

The unique characteristic that the vehicle has is that it can actually convert from this autonomous vehicle into one that is tethered to the surface vessel.
The Nereus tether is quite unique.

We actually dangle a reinforced cable over the side of the ship down to a point where the ocean is quite quiet. And from that point to the bottom, we actually tether the vehicle with this tiny slender fiber, something that's approximately the size of a human hair.

In ROV mode, that cable allows us to have direct control over the vehicle's actions because there are certain functions that the vehicle has to perform that require human ability to adapt to situations and to actually guide the manipulator arm.

So images come back on the fiber and we send commands down to the vehicle over that same fiber.

Nereus represented sort of a step change, in an evolutionary sense, to improving our ability to understand the oceans through the use of technology.  

 From BBC by Jonathan Amos

One of the world's most capable deep-sea research subs has been lost.

The robotic vehicle Nereus went missing while exploring one of the ocean's deepest spots: the Kermadec Trench, which lies north east of New Zealand.

Mapping with Multibeam from Woods Hole Oceanographic Inst.

Deep unknown. The Kermadec trench off New Zealand

Using one of the most advanced robotic submersibles in the world, scientists have just plunged to one of the deepest points on Earth.

Surface debris was found, suggesting the vessel suffered a catastrophic implosion as a result of the immense pressures where it was operating some 10km (6.2 miles) down.

Nereus was a flagship ocean explorer for the US science community.
"Nereus helped us explore places we've never seen before and ask questions we never thought to ask," said Timothy Shank, from the Woods Hole Oceanographic Institution (WHOI), which managed the sub's activities.
"It was a one-of-a-kind vehicle that even during its brief life brought us amazing insights into the unexplored deep ocean, addressing some of the most fundamental scientific problems of our time about life on Earth."

 Nereus was a new class of robotic vehicle, capable of descending into parts of the ocean that have previously been unexplored, and I think it's fair to say, that will result in new discoveries about our ocean environment.

The $8m (£4.7m) robot was built in 2008 and could operate in an autonomous mode or remotely controlled via a tether to a support ship to explore the Earth's deepest oceanic trenches.
It used a lot of innovative technologies that allowed it to do things and go places that were off-limits to other research submersibles.
These technologies included rechargeable lithium-ion batteries, similar to those used in laptop computers, for extended power, and single-hair's-width fibre-optic cables - borrowed from torpedoes - for control and telemetry.

Leading British oceanographer Jonathan Copley, from the University of Southampton, said the loss of an underwater vehicle was an ever-present risk.
"To obtain some kinds of knowledge - particularly when physical samples are required for analysis - there is no alternative to sending equipment into the deep ocean, because the ocean's watery veil masks its depths from many forms of 'remote sensing'", he wrote on a University of Southampton blog this weekend.
"And although we have learned a lot from a century or so of largely 'blind sampling' by equipment such as trawls and seabed corers (which are still fine for answering some questions in some areas), we now often require more detailed sampling and surveying, using deep-sea vehicles, to answer further questions."

Links :

• WHOI : A sad day

West Antarctic glacier loss appears unstoppable

A new study by researchers at NASA and the University of California, Irvine, finds a rapidly melting section of the West Antarctic Ice Sheet appears to be in an irreversible
state of decline, with nothing to stop the glaciers in this area from melting into the sea.

From NASA

A new study by researchers at NASA and the University of California, Irvine, finds a rapidly melting section of the West Antarctic Ice Sheet appears to be in an irreversible state of decline, with nothing to stop the glaciers in this area from melting into the sea.

A new study by researchers at NASA's Jet Propulsion Laboratory and the University of California, Irvine, finds that a rapidly melting section of the West Antarctic Ice Sheet appears to be in an irreversible state of decline, with nothing to stop the entire glacial basin from melting into the sea.
Three major lines of evidence point to the glaciers' eventual demise: their flow speeds and how they change with time, how much each glacier is floating on seawater rather than lying on land, and the slope of the terrain they are flowing over and its depth below sea level.
These glaciers already contribute significantly to sea level rise, releasing as much ice into the ocean each year as the entire Greenland Ice Sheet does.

The study presents multiple lines of evidence, incorporating 40 years of observations that indicate the glaciers in the Amundsen Sea sector of West Antarctica "have passed the point of no return," according to glaciologist and lead author Eric Rignot, of UC Irvine and NASA's Jet Propulsion Laboratory in Pasadena, California.
The new study has been accepted for publication in the journal Geophysical Research Letters.

These glaciers already contribute significantly to sea level rise, releasing almost as much ice into the ocean annually as the entire Greenland Ice Sheet.
They contain enough ice to raise global sea level by 4 feet (1.2 meters) and are melting faster than most scientists had expected.
Rignot said these findings will require an upward revision to current predictions of sea level rise.
"This sector will be a major contributor to sea level rise in the decades and centuries to come," Rignot said. "A conservative estimate is it could take several centuries for all of the ice to flow into the sea."

Three major lines of evidence point to the glaciers' eventual demise: the changes in their flow speeds, how much of each glacier floats on seawater, and the slope of the terrain they are flowing over and its depth below sea level.
In a paper in April, Rignot's research group discussed the steadily increasing flow speeds of these glaciers over the past 40 years.
This new study examines the other two lines of evidence.

 Thwaites Glacier. 

Image credit: NASA

The glaciers flow out from land to the ocean, with their leading edges afloat on the seawater.
The point on a glacier where it first loses contact with land is called the grounding line.
Nearly all glacier melt occurs on the underside of the glacier beyond the grounding line, on the section floating on seawater.

Just as a grounded boat can float again on shallow water if it is made lighter, a glacier can float over an area where it used to be grounded if it becomes lighter, which it does by melting or by the thinning effects of the glacier stretching out. The Antarctic glaciers studied by Rignot's group have thinned so much they are now floating above places where they used to sit solidly on land, which means their grounding lines are retreating inland.

"The grounding line is buried under a thousand or more meters of ice, so it is incredibly challenging for a human observer on the ice sheet surface to figure out exactly where the transition is," Rignot said.
"This analysis is best done using satellite techniques."

Grouunding Line retreat

The team used radar observations captured between 1992 and 2011 by the European Earth Remote Sensing (ERS-1 and -2) satellites to map the grounding lines' retreat inland.
The satellites use a technique called radar interferometry, which enables scientists to measure very precisely -- within less than a quarter of an inch -- how much Earth's surface is moving.
Glaciers move horizontally as they flow downstream, but their floating portions also rise and fall vertically with changes in the tides.
Rignot and his team mapped how far inland these vertical motions extend to locate the grounding lines.

The accelerating flow speeds and retreating grounding lines reinforce each other.
As glaciers flow faster, they stretch out and thin, which reduces their weight and lifts them farther off the bedrock.
As the grounding line retreats and more of the glacier becomes waterborne, there's less resistance underneath, so the flow accelerates.

  Greenland and Antarctic ice sheets

Slowing or stopping these changes requires pinning points -- bumps or hills rising from the glacier bed that snag the ice from underneath.
To locate these points, researchers produced a more accurate map of bed elevation that combines ice velocity data from ERS-1 and -2 and ice thickness data from NASA's Operation IceBridge mission and other airborne campaigns.
The results confirm no pinning points are present upstream of the present grounding lines in five of the six glaciers.
Only Haynes Glacier has major bedrock obstructions upstream, but it drains a small sector and is retreating as rapidly as the other glaciers.

 West Antarctica bed topography. Areas colored brown are below sea level. Sea level itself is colored yellow, and green areas are above sea level. Image credit: NASA/GSFC/SVS

The bedrock topography is another key to the fate of the ice in this basin.
All the glacier beds slope deeper below sea level as they extend farther inland.
As the glaciers retreat, they cannot escape the reach of the ocean, and the warm water will keep melting them even more rapidly.

 The glaciers studied by Rignot's research team.

Red indicates areas where flow speeds have increased over the past 40 years.

The darker the color, the greater the increase.

The increases in flow speeds extend hundreds of miles inland.

Image credit: Eric Rignot

The accelerating flow rates, lack of pinning points and sloping bedrock all point to one conclusion, Rignot said.
"The collapse of this sector of West Antarctica appears to be unstoppable," he said.
"The fact that the retreat is happening simultaneously over a large sector suggests it was triggered by a common cause, such as an increase in the amount of ocean heat beneath the floating sections of the glaciers. At this point, the end of this sector appears to be inevitable."

 The Amundsen Sea glacier beds are below sea level and slope deeper as they continue inland.

This image shows the beds of Thwaites and Haynes glaciers, with colors indicating depth.

The blue area under Thwaites Glacier is almost three-quarters of a mile below sea level.

Image credit: Eric Rignot

Because of the importance of this part of West Antarctica, NASA's Operation IceBridge will continue to monitor its evolution closely during this year's Antarctica deployment, which begins in October.
IceBridge uses a specialized fleet of research aircraft carrying the most sophisticated suite of science instruments ever assembled to characterize changes in thickness of glaciers, ice sheets and sea ice.

Links :

• NYT : Scientists warn of rising oceans from Polar Melt