A new way to track bigeye tuna

Janet Lathrop at UMassAmherst News & Media Relations: A first-of-its-kind study of bigeye tuna movements in the northwestern Atlantic Ocean led by Molly Lutcavage, director of the Large Pelagics Research Center at the University of Massachusetts Amherst, found among other things that these fish cover a wide geographical range with pronounced north-south movements from Georges Bank to the Brazilian shelf, and they favor a high-use area off Cape Hatteras southwest of Bermuda for foraging.

This NOAA-funded research, which used a new approach to study one of the most important commercial tuna species in the Atlantic, provides the longest available fishery-independent record of bigeye tuna movements to date. Data should help researchers to further characterize habitat use and assess the need for more monitoring in high-catch areas.

...Fisheries oceanographer Lutcavage says, “Although Atlantic bigeye tuna are delivering high prices to the U.S. commercial fleet and are highly sought by recreational fishermen and fishing tournaments, there’s been a surprising lack of scientific research on this species. And in contrast to the Pacific, where tuna fisheries programs have deployed over 400,000 tags over 25 years, the Atlantic lacks the fisheries infrastructure that would increase the odds of reco
vering tags. We have to rely on popup satellite tags that are fishery independent to make sure we get information back from the tuna.”

...Working with pelagic longline vessel captains Scott Drabinowicz and John Caldwell of the FV Eagle Eye II out of Fairhaven, Mass., Lutcavage, with LPRC colleagues Tim Lam and doctoral candidate Ben Galuardi, deployed 21 pop-up satellite archival tags (PSAT) on adult bigeye tuna between 2008 and 2010 in the northwest Atlantic. The sea captains fit tags on fish in good condition and return them to the sea. The PSATs were programmed to record relative light level, temperature and pressure (depth) every two minutes for eight or 12 months.

...Lam explains, “Bigeye tuna dive deeply, like clockwork, at dusk and dawn, making it hard to use light-based geolocation methods to estimate their daily locations. Here, we showcase a new positioning technique to get around the problem of low light levels at depth by using temperature and the bigeyes’ spatial ecology and movements in the western Atlantic. But there’s much more to learn.”

The authors hope their results will inform the International Commission for the Conservation of Atlantic Tuna’s upcoming tagging effort and assist ICCAT scientists as they plan new research to better understand the population....

Pelagic longline vessel Captain Scott Drabinowicz and crew preparing to deploy a tag from the deck of the FV Eagle Eye II. From the UMass Amherst website

Scientists discover link between climate change and ocean currents during the last six million years

AlphaGalileo via Royal Hollaway, University of London: Scientists have discovered a relationship between climate change and ocean currents over the past six million years after analysing an area of the Atlantic near the Strait of Gibraltar, according to research published today (Friday, 13 June) in the journal Science.

An expedition of scientists, jointly led by Dr Javier Hernandez-Molina, from the Department of Earth Sciences at Royal Holloway, University of London, examined core samples from the seabed off the coast of Spain and Portugal which provided proof of shifts of climate change over millions of years.

The team also discovered new evidence of a deep-earth tectonic pulse in the region, as well as thick layers of sand within mountains of mud in a vast sheet, spreading out nearly 100km into the Atlantic from the Gibraltar gateway. The quantity of sand is far more than was expected and has been caused by the strength, speed and long duration of bottom currents flowing through the Strait of Gibraltar from the Mediterranean.

“The sediments we examined show various shifts of climate change over millions of years”, Dr Hernandez-Molina said. “In addition, our findings could herald a significant shift in future targets for oil and gas exploration in deep-water settings. The thickness, extent and properties of these sands make them an ideal target in places where they are buried deep enough to allow for the trapping of hydrocarbons. The sand is especially clean and well sorted and therefore very porous and permeable.”

The expedition, carrying an international team of 35 scientists from 14 countries, recovered 5km of core samples from an area along the Gulf of Cadiz and west of Portugal.

The research found that a powerful cascade of Mediterranean water spilling into the Atlantic was scouring the rocky seafloor, carving deep-sea channels and building up mountains of mud. This is due to Mediterranean water being saltier than the Atlantic and therefore denser, causing it to plunge downwards.

Dr Hernandez-Molina added: “We set out to understand how the Strait of Gibraltar acted first as a barrier and then a gateway over the past six million years. The fascinating results we came back with have hugely increased our understanding of the Mediterranean Outflow Water (MOW) that flows through the Gibraltar gateway and have led to some key discoveries about the relationship between climatic shifts, deep-water circulation and plate tectonic events over a huge timescale.”...

NASA image of the Straits of Gibraltar

Unstable Atlantic deep ocean circulation under future climate conditions

AlphaGalileo via University of Bergen: A new study looking at past climate change, asks if these changes in the future will be spasmodic and abrupt rather than a more gradual increase in the temperature.

Today, deep waters formed in the northern North Atlantic fill approximately half of the deep ocean globally. In the process, this impacts on the circum-Atlantic climate, regional sea level, and soak up much of the excess atmospheric carbon dioxide from industrialisation — helping to moderate the effects of global warming. Changes in this circulation mode are considered a potential tipping point in future climate change that could have widespread and long-lasting impacts including on regional sea level, the intensity and pacing of Sahel droughts, and the pattern and rate of ocean acidification and CO2 sequestration.

Until now, this pattern of circulation has been considered relatively stable during warm climate states such as those projected for the end of the century. A new study led by researchers from the Bjerknes Centre of Climate Research at the University of Bergen (UiB) and Uni Research in Norway, suggests that Atlantic deep water formation may be much more fragile than previously realised.

...“Our study demonstrates that deep water formation can be disrupted by the freshening of the regional surface water, which might happen due to enhanced precipitation and glacier melting under future climate change scenarios,” says Yair Rosenthal, a co-author on the paper.

...Many models have actually predicted a slow and gradual decline in North Atlantic circulation over the next century. However, different models offer widely different scenarios for what will happen in the future. While the climate of the last interglacial is not exactly what will be the case in a future greenhouse world, it does share some features, including being fresher and warmer by a few degrees Celsius in the northern Atlantic....

Ocean Circulation Conveyor Belt. The ocean plays a major role in the distribution of the planet's heat through deep sea circulation. This simplified illustration shows this "conveyor belt" circulation which is driven by the difference in heat and salinity. Records of past climate suggest that there is some chance that this circulation could be altered by the changes projected in many climate models.  US federal government image

North and tropical Atlantic Ocean bringing climate change to Antarctica

Newswise via New York University: The gradual warming of the North and Tropical Atlantic Ocean is contributing to climate change in Antarctica, a team of New York University scientists has concluded. The findings, which rely on more than three decades of atmospheric data and appear in the journal Nature, show new ways in which distant regional conditions are contributing to Antarctic climate change.

“Our findings reveal a previously unknown—and surprising—force behind climate change that is occurring deep in our southern hemisphere: the Atlantic Ocean,” says Xichen Li, a doctoral student in NYU’s Courant Institute of Mathematical Sciences and the study’s lead author. “Moreover, the study offers further confirmation that warming in one region can have far-reaching effects in another.”

...Using a time-series analysis, in which the scientists matched changes in the North and Tropical Atlantic’s SST with subsequent changes in Antarctic climate, the researchers found strong correlations. Specifically, they observed that warming Atlantic waters were followed by changes in sea-level pressure in the Antarctic’s Amundsen Sea. In addition, these warming patterns also preceded redistribution of sea ice between the Antarctic’s Ross and Amundsen-Bellingshausen-Weddell Seas.

...The first part of the study, using the observational data, found a link, or correlation, between the Atlantic and Antarctic data sets. But a correlation means simply that two things appear to happen in conjunction and does not explain what may be causing a phenomenon. The second used a global atmospheric model, which allowed the researchers to create a simulated warming of the North Atlantic. The model responded, as the researchers had suspected, by "changing" the climate in Antarctica.

"While our data analysis showed a correlation, it was the use of a state-of-the-art computer model that allowed us to see that North Atlantic warming was causing Antarctic climate change and not vice versa," he said.

The study’s findings raise a number of deeper questions, such as, is Antarctic sea-ice change fundamentally different from the well-reported changes in the Arctic? In contrast to the sea-ice decline over the Arctic, Antarctic sea ice has not diminished. Rather, it has redistributed itself in ways that have perplexed scientists, with declines in some areas and increases in others....

The first flight of Operation Ice Bridge’s Antarctic campaign flew Oct. 16, 2009, along the Amundsen Coast. The aircraft’s downward-looking Digital Mapping System camera captured images of sea ice from an altitude of at least 20,000 feet.

Insight into Saharan dust migration

Terra Daily via SPX:  Satellite pictures of Saharan dust clouds have been in the news all summer, but to Shankar Chellam, they have just raised more questions. How much impact did the Saharan dust have on Houston's air? Is it more toxic than our home-grown dust?

...Clouds of African dust often migrate across the Atlantic Ocean during summer months, affecting Houston's air quality from mid-June through mid-September. Chellam said it's especially prevalent in late August and early September. The dust, whipped up by sandstorms in northwest Africa and carried by trade winds across the Atlantic Ocean, takes about 10 days to two weeks to reach the United States and, ultimately, Houston.

...Chellam became interested after he noticed "the most curious coincidence" as he was collecting data on industrial air pollution outside plants along the Houston Ship Channel in 2008. He began the project expecting that the plants would emit a constant amount of pollution, as measured from just beyond their property lines. But he discovered that on some days they emitted relatively little, while emissions were much higher on other days.

"What we quickly realized was that the impact of the refineries varied with time," he said. "We naively had gone into our research expecting that if we took three months of data, we would get an average." A five-day period in July and August 2008 showed a large variation. That coincided with an influx of Saharan dust, Chellam said.

To determine the actual impact of the Saharan dust required scientific detective work. Chellam and his team determined the "fingerprint" of the African dust, allowing them to differentiate it from other types of pollutants in their samples: industrial dust, vehicle pollutants and smoke from wildfires, among other things....

Dust from the Sahara blowing over the Atlantic Ocean. Image from NASA

Tropical Depression 5 becomes Tropical Storm Erin over Atlantic

NBC Miami: Tropical Depression 5 became Tropical Storm Erin early Thursday after forming over the far east Atlantic Ocean late Wednesday, the National Hurricane Center in Miami said.

As of 8 a.m., the storm had maximum sustained winds of 40 mph as it moved west-northwest at 16 mph about 65 miles west-southwest of Brava in the Cape Verde Islands, according to the NHC.

A tropical storm warning was issued for the southern Cape Verde Islands of Maio, Santiago, Fogo and Brava.

Erin is expected to strengthen during the next couple days and will decrease in speed, the NHC said.

The storms will move away from the Cape Verde Islands later Thursday and is expected to keep moving to the west-northwest….

NOAA graphic of TS Erin's predicted track

Atlantic hurricane season may spark to life next week

Brian K. Sullivan: The Atlantic hurricane season is about to enter its most active phase as conditions for the powerful storms improve across the basin.

Wind shear that can tear budding storms apart has been decreasing, said Dan Kottlowski, an expert senior meteorologist at AccuWeather Inc. in State College, Pennsylvania. At the same time, the potential for more robust tropical waves, the seeds for hurricanes, is increasing.

The U.S. National Hurricane Center is currently tracking such a wave just off the coast of Africa. It has a 20 percent chance of becoming a tropical system in the next five days.

“There are six or seven blobs of thunderstorms marching across Africa right now, some of these will be tropical waves,” Kottlowski said by telephone. “Next week looks very promising for development over the eastern Atlantic.”

The Atlantic season begins on June 1 and the most active portion falls between Aug. 20 and October. Sept. 10 is the statistical peak of the period, according to the center in Miami.

The storms are followed closely by energy companies and commodities traders because they can destroy crops and disrupt natural gas and oil production and processing…

The eyewall of Hurricane Isabel in 2003, from NOAA

Atlantic warming points to malaria risk... in India

Terra Daily via (AFP): Health watchdogs monitoring the risk of malaria in India should keep a close eye on what's happening thousands of kilometres (miles) away in the Atlantic, an unusual study published on Sunday suggests. The temperature of the sea surface in the tropical South Atlantic is a big determinant for levels of monsoon rain, which in turn is the big factor for malarial mosquitoes, it says.

Researchers led by Mercedes Pascual at the University of Michigan compared maps of monsoon rainfall and malaria epidemics in the desert fringe of northwestern India with a global map of sea-surface temperatures.

What struck them was a clear link between abnormally cold temperatures in the tropical South Atlantic in July and a regional increase in malaria in the ensuing September-December period. Previous research has suggested that the vast body of water in the Atlantic has a much bigger impact on the global climate system than thought.

When this volume of ocean warms or cools, it has a knock-on effect on adjoining seas. The transfer of heat has an impact on ocean circulation and rainfall, affecting for instance the relationship between the monsoon of the Indian Ocean and El Nino, the pendulum weather swing in the Pacific....

Histopathology of malaria exoerythrocytic forms in liver. Histopathology of malaria exoerythrocytic forms in liver. Parasite. Content Providers(s): CDC/Dr. Melvin Creation Date: 1973

Warm North Atlantic ocean causing UK's wet summers, study shows

Damian Carrington in the Guardian (UK): The UK's dismal recent summers can be blamed on a substantial warming of the North Atlantic ocean in the late 1990s, according to new scientific research. The shift has resulted in rain-soaked weather systems being driven into northern Europe, increasing summer rainfall by about a third.

The pattern is likely to revert to drier summers and may do so suddenly, according to Professor Rowan Sutton, at the University of Reading, who led the work. "I can't guarantee it but it is likely," he said. "However we are not sure of the timing, which is what every one wants to know – but we are working on this now." Sutton added that when the switch occurs, it could happen as rapidly as over two to three years.

The summer of 2012 was the wettest in a century and follows a series of above average years for summer rainfall. Sutton's team, who published their study in Nature Geoscience, examined over a century of data and found that the temperature of the North Atlantic remains above or below the long term average for decades at a time. The periods of warmer temperature, the latest of which started in the late 1990s, were found to correlate with wet summers in Northern Europe and hotter, drier summers in the Mediterranean. The team used existing detailed climate simulations to demonstrate a causal link between the warmer oceans and the change in the weather.

Sutton said these shifts have been occurring for many hundreds of years, but that global warming was also having an impact. "It is not now purely natural or purely a manifestation of human-induced climate change," he said. "There is lot of evidence to show that climate change is changing the timing and amplitude of the temperature changes." For example, he said, the cooler period from the 1960s to the 1980s occurred when soot and other pollution from dirty power stations cooled the planet....

A rain in 2008, ruining a silage crop in Devon, shot by paul dickson, Wikimedia Commons via Geograph UK, under the Creative Commons Attribution-Share Alike 2.0 Generic license

Warming Atlantic primes the Amazon for fire

Barbara Fraser for The Daily Climate: ...Scientists used to think the rainforest, especially in the western Amazon, was too wet to burn. But major fire seasons in 2005 and 2010 made them reconsider.

Fires are a major source of carbon emissions in the Amazon, and scientists are beginning to worry that the region could become a net emitter, instead of a carbon sink. New findings link rising ocean temperatures off the northern coast of Brazil to changing weather patterns: As the Atlantic warms, it draws moisture away from the forest, priming the region for bigger fires.

"We are reaching a tipping point in terms of drought, beyond which these forests can catch fire," says Daniel Nepstad, international program director at the Amazon Environmental Research Institute in Brasília, Brazil.

The 2005 drought – considered a once-in-a-century event – resulted in unprecedented wildfires in Acre, the western Brazilian state bordering Peru. Flames scorched the tree canopy, and at one point the front face of the fire stretched nearly seven miles. As many as 1.2 million acres of forests were affected in Acre and the neighboring regions of Pando in Bolivia and Madre de Dios in Peru. Officials estimated upwards of $100 million in economic damages...

NASA image of fire and deforestation near Rondonia, Brazil

Katia ramps up power, but seen missing US east coast

Pascal Fletcher in Reuters: Hurricane Katia powered up to a major Category 4 storm on Monday, but was expected to veer away from the U.S. East Coast later this week, avoiding a direct hit on a seaboard already battered by Hurricane Irene. The U.S. National Hurricane Center warned, however, that U.S. East Coast beaches should still watch out in the coming week for large swells generated by Katia that could cause life-threatening coastal surf and rip currents.

By late Monday evening, Katia's winds had strengthened to 135 miles per hour, making it a Category 4 hurricane on the five-step Saffir-Simpson intensity scale as it tracked northwestward on a path over the ocean between Bermuda and the Caribbean, the Miami-based center said. The storm was moving toward the northwest at about 10 mph and the hurricane center said it was expected to continue in this general direction through Wednesday.

The center said some fluctuations in strength were possible during the next 24 hours, followed by a slow weakening. NHC hurricane specialist Robbie Berg told Reuters the greatest threat from Katia for the U.S. eastern seaboard was likely to be the large swells and resulting dangerous coastal surf and currents the storm generated on its path...

Katia was a tropical storm gathering energy over the Atlantic Ocean when one of the Expedition 28 crew took this photo on Aug. 31, 2011, from aboard the International Space Station. The picture, taken with a 12-mm focal length, was captured at 14:09:01 GMT. Later in the day Katia was upgraded to hurricane status. Two Russian spacecraft -- a Progress and a Soyuz --can be seen parked at the orbital outpost on the left side of the frame. From NASA

Katia expected to become hurricane

Brian K. Sullivan in Bloomberg News: Tropical Storm Katia may grow into a hurricane in the next two days as it moves west-northwest through the mid-Atlantic Ocean, according to the National Hurricane Center in Miami.

The storm’s winds increased to 45 miles (72 kilometers) per hour from 40 mph earlier today as it churned across the Atlantic about 630 miles west-southwest of Cape Verde, according to a center advisory issued at about 11 a.m. New York time.

“Continued gradual strengthening is forecast and Katia is expected to become a hurricane by late Wednesday or early Thursday,” the center said. Its current track and intensity forecasts have the storm growing into a Category 3 hurricane on the Saffir-Simpson five-step scale.

Computer forecast models suggest Katia will turn into the Northern Atlantic, a maneuver meteorologists refer to as recurving. The move would mean Katia would miss the U.S., which was struck last weekend by Hurricane Irene, a storm that killed at least 40, cut power to 8 million homes and businesses and caused an estimated $2.6 billion in damage.

...Katia is the 11th named storm of this Atlantic hurricane season, which runs from June 1 to Nov. 30. The average hurricane season usually produces that total, according to the hurricane center....

A predicted track for Tropical Storm Katia from the National Hurricane Center, as of August 30, 2011, at 5:00 pm EST

Officials eye Irene, begin preparations

Ray Gronberg in the Herald-Sun (North Carolina): Local officials have begun preparing for the arrival of Hurricane Irene, even as they hope weather patterns push the storm far enough to the east for the Triangle to miss its worst effects. Projections at 5 p.m. on Tuesday were calling for Irene to pass along the North Carolina coast on Saturday.

Federal officials, though, cautioned that the season’s ninth named hurricane is a big storm that will make itself felt up and down the county’s eastern seaboard. “Just about everyone who lives on the East Coast needs to be prepared for it,” National Hurricane Center Director Bill Read told reporters during a Tuesday morning conference call.

To Federal Emergency Management Director Craig Fugate, Irene’s predicted track at that time was looking like those of Hurricanes Bertha and Floyd, 1996 and 1999 storms, respectively, that caused significant destruction in eastern North Carolina. A subsequent update of the projected track moved it a bit more to the east. But state and local officials are taking no chances.

In Durham, Emergency Management Director Jeff Batten asked police, fire and other officials to review their emergency plans, to ensure that each of their departments “understand what their role and responsibilities are” if Irene causes trouble here....

Irene became the first hurricane of the 2011 Atlantic season this weekend. The storm, with 80 mph sustained winds, passed over Puerto Rico on Sunday, and is now on a path towards the Bahamas and Florida coastline. A ridge of high pressure to the north of the storm, around Bermuda, should stay in place over the next few days, forcing the storm along a west-northwest path. Irene is expected to strengthen over the next 48 hours, potentially into a Category 2 hurricane. This image from the GOES-East satellite shows the storm on August 22, 2011 at 1345z.

Scientists find 'drastic' weather-related Atlantic shifts

Terra Daily via AFP: Scientists have found evidence of a "drastic" shift since the 1970s in north Atlantic Ocean currents that usually influence weather in the northern hemisphere, Swiss researchers said on Tuesday. The team of biochemists and oceanographers from Switzerland, Canada and the United States detected changes in deep sea Atlantic corals that indicated the declining influence of the cold northern Labrador Current.

They said in the US National Academy of Science journal PNAS that the change "since the early 1970s is largely unique in the context of the last approximately 1,800 years," and raised the prospect of a direct link with global warming.

The Labrador Current interacts with the warmer Gulfstream from the south. They in turn have a complex interaction with a climate pattern, the North Atlantic Oscillation, which has a dominant impact on weather in Europe and North America. Scientists have pointed to a disruption or shifts in the oscillation as an explanation for moist or harsh winters in Europe, or severe summer droughts such as in Russia, in recent years.

One of the five scientists, Carsten Schubert, of the Swiss Federal Institute of Acquatic Sciences and Technology (EAWAG), underlined that for nearly 2,000 years the sub polar Labrador current off northern Canada and Newfoundland was the dominant force. However that pattern appeared to have only been repeated occasionally in recent decades. "Now the southern current has taken over, it's really a drastic change," Schubert told AFP, pointing to the evidence of the shift towards warmer water in the northwest Atlantic….

A US Coast Guard map of the Labrador Current

Trio of storms swirls in Atlantic and Caribbean

Reuters: A trio of potentially dangerous storms swirled over the Atlantic Ocean on Tuesday, as Tropical Storm Karl formed in the Caribbean on a path that could take it over oil-production facilities in Mexico's Bay of Campeche. The threat posed by Karl, which forecasters say will enter the oil-rich Gulf of Mexico, came as Tropical Storm Julia grew in the far eastern Atlantic into the fifth hurricane of the Atlantic storm season and Hurricane Igor remained a dangerous Category 4 storm.

Neither hurricane posed an immediate threat to land or energy interests, but Igor could threaten Bermuda by the weekend. Karl, located about 230 miles east of Chetumal, Mexico, had maximum sustained winds of about 45 miles per hour on Tuesday afternoon, the U.S. National Hurricane Center said.

The 11th named storm of the Atlantic hurricane season was expected to churn west-northwest across Mexico's Yucatan Peninsula on Wednesday and then plow into the Bay of Campeche in the southwest Gulf of Mexico before moving inland in central Mexico.

The system was expected to miss key U.S. oil and natural gas rigs in the northern part of the Gulf of Mexico. But forecasters said the storm, which some computer models showed becoming a Category 1 hurricane, could hit Mexican oil interests….

Tropical Storm Karl yesterday

Hurricane Igor strengthens rapidly

Reuters: Hurricane Igor strengthened rapidly over the Atlantic Ocean on Sunday, becoming a large and dangerous Category 4 storm as it spun menacingly westward. Igor, capable of causing catastrophic damage, posed no imminent threat to land or energy interests.

But the U.S. National Hurricane Center said Igor was packing top sustained winds of 140 miles per hour, making it a "major" Category 4 storm on the five-step Saffir-Simpson scale of hurricane intensity. "Igor continues to intensify at a rapid pace," the Miami-based hurricane center said.

…Some additional strengthening of Igor was expected over the next three days but it was expected to fall short of becoming a Category 5 storm before it begins to weaken gradually on Thursday. Computer models project Igor, which became the fourth hurricane of the 2010 Atlantic season late on Saturday, would stay in the Atlantic for the coming days and not enter the Gulf of Mexico, where U.S. oil and gas operations are clustered….

Hurricane Igor yesterday

Hurricane Igor picks up strength in Atlantic Ocean

Reuters: Hurricane Igor gathered strength as it churned westward in the Atlantic Ocean on Sunday and appeared poised to gain even more intensity in the coming days but posed no imminent threat to land or energy interests. The U.S. National Hurricane Center said Igor, the fourth hurricane of the 2010 Atlantic season, had maximum sustained winds of about 80 miles per hour, making it a Category 1 hurricane on the five-step Saffir-Simpson scale.

Igor reached hurricane status late on Saturday. At 5 a.m. EDT (0900 GMT), the hurricane was located about 1,230 miles east of the Leeward Islands, and was moving westward at 18 miles per hour, the hurricane center said. "Additional strengthening is forecast and Igor could reach major hurricane strength by Monday night," the Miami-based center added….

September 10, 2010, when Igor was a tropical storm

Cape Verde on alert as Tropical Storm Igor forms

Terra Daily via AFP: Tropical Storm Igor formed Wednesday in the eastern Atlantic and took aim for the Caribbean, prompting the government of Cape Verde to place its citizens on alert. A bulletin from the Miami-based National Hurricane Center said the government of Cape Verde had issued a tropical storm watch for southern islands in the group, including Maio, Sao Tiago, Fogo and Brava.

As of 1500 GMT, Igor was about 95 miles (155 kilometers) southeast of the southernmost Cape Verde Islands, packing sustained winds of 40 miles per hour (65 kilometers per hour) and moving slowly west. "On the forecast track, the center of Igor should pass south of the Cape Verde Islands by tomorrow," the NHC report said, adding that "slow strengthening" would occur in the coming days….

Locator map of Cape Verde by that indefatigable cartographer, Rei-artur, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 2.5 Generic

Storms ramp up in Atlantic

Sydney Morning Herald: Hurricane Danielle, the strongest storm of the Atlantic season, surged to a Category Four intensity Friday followed close behind by Earl, a tropical storm that could hit the Caribbean within days, US forecasters said. "Danielle is a Category Four hurricane on the Saffir-Simpson (five-step) scale," with sustained winds of 135 miles (215 kilometers) per hour, the Miami-based National Hurricane Center said in a bulletin just before 0900 GMT. "Some additional strengthening is possible in the next 24 hours."

Danielle -- the second and strongest to date of the 2010 Atlantic hurricanes -- is forecast to track well east of Bermuda and then curl to the northeast and out to sea. But the hurricane will likely drench the island chain with rain and the NHC said "interests in Bermuda should monitor the progress of Danielle."

…Danielle surged in strength in just a few hours from Category Two to Category Four, the second highest level on the NHC's scale. Category Four storms cause "catastrophic damage" when they make landfall, with "a very high risk of injury or death to people, livestock, and pets due to flying and falling debris," according to the NHC. Shortly before 0900 GMT the hurricane was 875 kilometers southeast of Bermuda and moving to the northwest at 19 kilometers per hour, but there were no coastal watches or warnings in effect, the center said.

Of greater concern out in the Atlantic was Tropical Storm Earl, which forecasters expect to reach hurricane status by late Saturday and then threaten the eastern Caribbean, including Puerto Rico, by late Monday or early Tuesday….

On August 22, Danielle was still a Tropical Depression

Sea level rise quickening along US Atlantic coast

Scientific Blogging: An international team of environmental scientists says that sea-level rise along the Atlantic Coast of the United States in the 20th century was 2 millimeters faster than at any point in the last 4,000 years. Sea-level rise prior to the 20th century is generally attributed to coastal subsidence. This occurs as land is lost to subsidence as the earth continues to rise in response to the removal of the huge weight of ice sheets during the last glacial period.

Using sediment cores from the U.S. Atlantic coast, researchers found significant spatial variations in land movement, with the mid-Atlantic coastlines of New Jersey, Delaware and Maryland subsiding twice as much as areas to the north and south. Coastal subsidence enhances sea-level rise, which leads to shoreline erosion and loss of wetlands and threatens coastal populations.

The researchers corrected relative sea-level data from tide gauges using the coastal-subsidence values. Results clearly show that the 20th-century rate of sea-level rise is 2 millimeters higher than the background rate of the past 4,000 years. Furthermore, the magnitude of the sea-level rise increases in a southerly direction from Maine to South Carolina. This is the first demonstrated evidence of this phenomenon from observational data alone. The team believes this may be related to the melting of the Greenland Ice Sheet and ocean thermal expansion.

The authors claim their study provides the first accurate dataset for sea-level rise for the U.S. Atlantic coast, identifying regional differences that arise from variations in subsidence and demonstrate the possible effects of ice-sheet melting and thermal expansion for sea level rise….

A barrier island in the Outer Banks, North Carolina. Shot by NOAA