Stress and effect on a vessel in severe weather conditions

Stress and effect on a vessel in severe weather conditions.

Recorded during passage from Suez Canal to Singapore, recorded in June 2008.

Big shore break

Gas Chambers is a fast, hollow and shallow point break type of wave.

Being that it is a high performance wave it is well suited for the average to pro level surfer.

Sandy's beach is the host of Gas Chambers, located on the North Shore of Oahu about a 1/4 of a mile north of Ehukai Beach Park and 1/2 a mile west of Sunset Beach Park.

Frigid Winter? Blame 4,000 years of wild Jet Streams

The polar jet stream can travel at speeds greater than 100 mph.

Here, the fastest winds are colored red; slower winds are blue.

From LivScience by Becky Oskin

This winter's wild weather got its start 4,000 years ago, a new study finds.
The roaring jet stream, whose swooping winds drove frigid cold in the East and record warmth in the West this winter, first started twisting and turning about 4,000 years ago, according to a new analysis of ancient rainfall records from North America.
Jet stream winds race from west to east, and kinks in the narrow atmospheric current can suck Arctic cold south or hold warm air in place.

The study shows the jet stream's plunging pattern is a long-standing natural phenomenon.
However, the findings also suggest that global warming may boost the frequency or intensity of the curves, which would mean more winter extremes in the United States and Canada, the researchers said.
The study was published today (April 16) in the journal Nature Communications.

"The pattern we've observed points to a strong potential for an increase in winter extremes in the future," said Gabe Bowen, a study co-author and paleoclimatologist at the University of Utah.
Bowen and his co-authors examined the 8,000-year history of a weather pattern called the Pacific-North America Teleconnection.
The teleconnection refers to blobs of high and low atmospheric pressure above the Pacific Ocean and North America that direct the jet stream's strength and location.

Lead study author Zhongfang Liu, now at the Tianjin Key Laboratory in China, tracked the jet stream's location for the past 8,000 years with oxygen isotopes (atoms of the same element with different numbers of neutrons) from caves and lake sediments.
The ratio of certain oxygen isotopes reveals the history of rainwater, such as how cold the air was when the water fell and where the water came from.
Looking at the rainwater's history helps trace the pattern of the jet stream, which drives storms across the continent.
The team also compared their rainfall records with tree ring records and more recent instrumental data.

What is the jet stream?

How does the jet stream affect our weather?

This animation explains how the jet stream works.

 The rainfall patterns reveal the jet stream was relatively "flat," moving straight and steady from about 8,000 to 4,000 years ago, the study reports.

Then, about 4,000 years ago, the amount of solar energy reaching the Northern Hemisphere dropped. (This drop was caused by Earth's 20,000-year precession, the slow change in its rotation axis.)

The change in the sun's energy altered worldwide climate, such as triggering a stronger El Niño/La Niña cycle and a shift in monsoonal rainfall over India and Pakistan.

The jet stream pattern also shifted 4,000 years ago, going from flat to curvy over a period of about 500 years, the researchers found.
For example, the isotopes show more Arctic air moving south in the East, and more tropical air heading north in the West, consistent with wrinkles in the jet stream.
The curves help explain why some parts of North America became colder or wetter, while others grew drier or warmer, Bowen said.
"We knew the changing seasonality of the climate in North America wasn't uniform, and we were able to link it to this change in the jet stream," Bowen said.

These maps show winter temperature patterns (top) and winter precipitation patterns (bottom) associated with a curvy jet stream.
Credit: Zhongfang Liu, Tianjin Normal University, China

Sun to blame?

So was this winter's bizarre weather the result of natural climate swings?
Not at all, Bowen said.
"All things being equal, with the solar forcing that kicked in 4,000 years ago, we'd actually expect to be heading the other way now and starting to decrease the jet stream curviness," Bowen told Live Science.

A short review of how the jetstream and Rossby waves work, and some emerging indications that the dynamics may be changing in a warming world.

Several recent studies have argued that the jet stream's twists and turns are being exacerbated by climate change.
That's because the jet stream's high-speed air current forms at the border between hot and cold air masses.
As global warming changes the distribution of hot and cold air on the planet, the location and pattern of the jet stream may change too.

"Whether the Pacific-North America Teleconnection will continue to vary in the future as it has for the past few thousand years will have important implications in terms of water availability and climate in the western United States," said Max Berkelhammer, a hydrologist at the University of Illinois, Chicago, who was not involved in the study

But until now, only a century of instrumental records have been available to model the jet stream's response to global warming.
The new study "gives us a good look at natural variability so that we can gain a better understanding about how the jet stream has responded to past changes," said Lesleigh Anderson, a research geologist with the U.S. Geological Survey who was not involved in the study
"This is what we need to know to better understand what could happen in the future with rising carbon dioxide."

Theories on how a South Korean passenger ferry suddenly sank

The vessel was travelling from Incheon port, in the north-west, to the southern resort island of Jeju.

Most of the people on board were high school students.

  

From CNN

As divers searched frigid waters off South Korea in low visibility, hoping to save hundreds of passengers, a dominant theory began to emerge about how the ferry sank.

Area of the sinking on the GeoGarage nautical chart viewer

It most likely struck something in the water, said Peter Boynton, a retired U.S. Coast Guard captain.
"The speed with which this ferry began to list and then roll over on its side suggests significant damage, most likely causing major flooding that would cause a vessel of this size -- almost 500 feet long -- to quickly roll onto its side. That's very likely the result of significant damage," he said.
Some passengers reported hearing a loud bang before the ship began sinking.
That could be from cargo shifting or "some other internal damage," Boynton told CNN's "New Day." "But it does sound, from initial reports, it was more likely that something was struck."

 Sewol route on MarineTraffic

When the ship left Seoul, it traveled through fog, which may have put it off course, said Mary Schiavo, former inspector general for the Department of Transportation.
"So if they hit something, that would have meant they were out of the channel, which is quite easy to do," Schiavo said.
But the South Korean Oceans and Fisheries Ministry said Thursday that the ferry did not deviate significantly from its intended route.
The agency approved the ferry's intended route, and "there was no huge difference between their plan and the actual track chart," spokesman Nam Jae Heon said.

 Rescue crews attempt to save passengers from the ferry.

Schiavo said other possibilities include engine failure or an explosion, particularly in the engine room.
"But that probably alone wouldn't account for the sinking this quickly. It probably was something else that happened," she said.
Making matters worse, the ferry carried dozens of vehicles. Once an auto deck is breached, "it's typically open to very significant flooding," Boynton said.
That could explain "why the ferry in just a matter of hours began to roll onto its side so quickly."
Coast guard and navy ships, as well as fishing boats, rushed into the area.

 Rescue teams and fishing boats try to rescue passengers on April 16.

For rescue divers, a combination of factors makes saving people especially difficult: very cold waters, strong currents and low visibility, made worse by nightfall.
"The underwater challenges are very, very significant and pose, I would think, tremendous risk for the people who I'm sure are doing their best to help," Boynton said.
For the passengers, the most immediate danger is the cold.
"Pretty much everyone we saw was wearing a life jacket," journalist Andrew Salmon reported on CNN International.
"So the concern is hypothermia. If you're not picked up within two hours, you're in significant danger -- your body core goes cold."

 Military and civilian ships and helicopters have been searching for survivors

Some of the rescued passengers report that when the ship began to sink, they were told to jump into the water immediately -- and not to take time to get into life boats.
Sometimes after a breach, as the water begins gushing in, "there's a sucking, there's a motion, that just makes it impossible to fight," Schiavo said.
"So the order to abandon ship might have indicated that. ... It's almost like a suction that occurs when the water starts coming on, and you can't fight it."
But other passengers said they were told to stay on the ship. Sometimes, "conflicting commands" are given, Schiavo said.
"There can be a lot of confusion in an event like this."

Links :

• BBC : South Korea ferry: Hundreds missing as ship sinks

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.  

8 charts have been updated in the Marine GeoGarage

(Linz March update published March 21, 2014) 

• NZ 48 Western Approaches to Cook Strait
• NZ 61 Karamea River to Stephens Island
• NZ 5322 Auckland Harbour East
• NZ 5323 Auckland Harbour West
• NZ 6154 Tory Channel Entrance and Picton Harbour
• NZ 7142 Greymouth Harbour and Approaches
• NZ 7654 Chalky and Preservation Inlets
• NZ 9558 Rarotonga

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.