Trouble brewing in the Atlantic

Hurricane Earl, now a Category 4 storm with sustained winds of 135 miles per hour, continues on a course that is projected to take it up along the Atlantic seaboard. Meanwhile, Tropical Storm Fiona threatens to overtake Earl and perhaps the two storms will merge.

Fiona's track is nearly the same as Earl's. Earl is moving at 13 miles per hour west-northwest. Fiona is moving at 24 miles per hour, also west-northwest. Both storms are skirting the Leeward Islands.

A large area of high pressure had settled over the eastern states and will dominate weather until later in the week. This will keep the storms out to sea, but their effects are likely to be felt along the coast. Earl is expected to reach the Outer Banks Thursday night and pass off the Jersey Coast on Friday.

Meanwhile, a new disturbance formed in the Eastern Atlantic late Monday.

Hurricane Earl headed up the coast

Forecasters at the National Hurricane Center project that Earl, a Category 4 hurricane with 135 mile-per-hour sustained winds as it brushed past Puerto Rico on Monday, will head up the Atlantic Coast later this week. It is projected to be off the Outer Banks by Thursday evening and off the Jersey Coast on Friday. Unlike Danielle, now downgraded to a tropical storm as it heads northeastward across the North Atlantic, Earl is tracking farther westward.

Meanwhile, another tropical storm was spawned Monday by a tropical wave that passed from the West Coast of Africa last Thursday and intensified late Monday into a tropical storm. Named Fiona, it was poorly organized Monday and following pretty much in Earl's wake across the tropical Atlantic.

Anyone planning coastal vacations beginning later this week should keep an eye on developments from Earl, and possibly Fiona.

Creating a haven

Adventures on Earth for September 1 edition of The Review
By George E. Beetham Jr.
The Earth formed some 4.6 billion years ago as material came together to form the planet. For another billion years, the planet would consist of rock and sea.
The seas were not the oceans of today. They were a primordial mix of chemicals that are toxic to life as we know it.
While there may have been some form of life present in those toxic seas, it would take the emergence of one life form that would transform the planet and open it up to life.
Cyanobacteria, or blue-green algae, synthesized sunlight to create energy, taking in carbon dioxide and giving off oxygen.
The cyanobacteria clumped together in mats on the floor of warm, very shallow seas. The organisms trapped sediments that cemented together, forming dome-shaped structures.
As the structures grew, the cyanobacteria moved up, reaching for the sun, staying above the now hardened structure below.
The structures are known as stromatolites. Stromatolites are among the planet’s earlies life forms, forming some 3.5 billion years ago.
Throughout the history of the Earth, stromatolites have ebbed and flowed. After their formation, living creatures grazed the algae at the top of the structure. When grazing creatures thrived, stromatolites began to disappear, emerging again when mass extinctions wiped out the grazers, and then waning as new grazers arose in the wake of the extinctions.
Today stromatolites are found at about a half dozen to a dozen known sites, some in oceans and some in lakes and inland seas.
They have been found in two locations in Western Australia and in the Bahamas.
Some were found in Yellowstone National Park.
Stromatolites are abundant in the fossil record. In particular, the Keyser Formation at the Silurian-Devonian boundary is noted for vast reefs of stromatolites.
A cliff in western Virginia shows stromatolites crowded together, one layer on top of another.
Stromatolites begin as small structures, growing outward as sediments get cemented. The layers are not unlike a cabbage or onion. Cross section of fossil stromatolites show this layering very well.
Because cyanobacteria have an unpleasant odor, biologists dubbed them “stinking cabbages.”
Unlike cabbage, stromatolites are hard rock in their interior. It is only on the upper outer surface that the cyanobacteria form.
Stromatolites are likely to endure as long as conditions are favorable on the planet. They will almost certainly outlive humans.
As living things go, stromatolites are less than spectacular. There is no colorful flower, no bright plumage, no luxuriant fur. There is just the cabbage-like head with perhaps a stalk below. They can surface at low tide and be submerged at high tide.
Yet they have endured through thick and thin for 3.5 billion years and will likely be around for another 3 billion or so years.
They gave us oxygen and made the planet a haven for life.

And now there are three

Tropical storm season kicked into high gear this week as Hurricane Danielle continues to track southeast of Bermuda, Tropical Storm Earl is heading toward the Windward Islands, and a new disturbance that came off the coast of Africa on Thursday is being watched by forecasters for possible development.
Danielle is expected to turn north, and then northeast, passing east of Bermuda on Saturday. Dangerous surf conditions will prevail in Bermuda and swells from Danielle will reach the US Coast on Saturday, creating dangerous rip currents.
Danielle is a Category IV hurricane with sustained winds of 135 miles per hour. The storm developed an eyewall on Thursday.

Earl is still a few days from making any landfall, but is slowly gaining strenth. It's sustained winds are at 45, but barometric pressure is slowly dropping.

The new disturbance was south of the Cape Verde Islands on Friday. Winds increased from 20 to 25 miles per hour from Thursday into Friday.

Now there are two named storms in the Atlantic

Hurricane Danielle strengthened today and has charted a course toward Bermuda. As of 5 p.m. Thursday, Danielle packed sustained winds of 110 miles per hour and was moving northwest at 14 miles per hour. The National Hurricane Center placed Danielle at 25.2 North, 57.0 West.

Tropical Depression 7 became Tropical Storm Earl on Wednesday afternoon. At 11 a.m. Thursday, Earl was at 14.9 North, 37.1 West, with sustained winds at 45 and moving west at 17 miles per hour. That location is at the middle of the Atlantic with a course toward the Windward Islands.

Sea surface temperatures and weather conditions are favorable for storm development.

Storm season picking up

A storm that emerged off the coast of Africa last Friday grew into Hurricane Danielle on Monday. On Tuesday the storm had reached the Mid-Atlantic between the Windward Islands and Cape Verde Islands and grew briefly to Category 2. By mid-day Tuesday Danielle encountered wind shear and dropped back to Category 1. The storm is expected to curve more to the north and pass east of Bermuda later in the week.

Meanwhile, another tropical wave passed off the coast of Africa on Monday and is expected to become Tropical Depression 7 later Tuesday and Hurricane Earl either late Tuesday or early Wednesday. This storm is expected to track in Danielle's wake.

Conditions in the tropical Atlantic remain favorable for hurricane development. Sea surface temperatures are well above 80 degrees, the temperature necessary for storm development. The heaviest part of tropical storm season continues into mid-September, with activity now picking up.

News from the Arctic

Adventures on Earth column for August 25, 2010
By George E. Beetham Jr.
Arctic sea ice has been melting during the summer of 2010 at near the record rate set in 2007. With about a month left in summer, this year could still set a new record.
Scientists have discovered that Arctic sea ice melts not from the top down, but from the bottom up. This means the temperature of the water is a larger factor than the temperature of the air above.
It also means the Arctic Ocean as a whole is quickly becoming warmer, and that spells trouble for species that depend on sea ice for their existence.
And that list of creatures is a lot larger than just polar bears and seals.
Indeed, creatures at the very base of the food chain will be affected as sea ice melts. Tiny crustaceans feed on algae under the sea ice. These creatures in turn feed larger predators, all the way up to seals, whales, and polar bears.
This alarming news is contained on a Planet Green Channel documentary, “Oceans Blue – Arctic Ocean,” that aired over the weekend. The cable network will rebroadcast the show at 5 p.m. Friday, 5 p.m,. Saturday, and 8 p.m. Sunday.
The Oceans Blue series is hosted by Philippe and Alexandra Cousteau.
Their work simply adds to alarming news about the Arctic this summer.
● Oceanographers have found that the thickest sea ice, which formerly formed the core around which sea ice reformed during autumn in the Arctic, is floating into warmer waters and it, too, is melting.
● The near record melting this summer follows a late-winter freeze that scientists thought would presage a cooler summer. Instead, it is warmer.
● Forest fires in Russia are affecting ice melt, adding to greenhouse gases and giving off smoke and soot that darken ice.
● Methane hydrates are melting more rapidly than predicted, releasing methane into the atmosphere where it acts as a greenhouse gas.
Sea ice, according to the Oceans Blue documentary, forms at a lower temperature than fresh water ice. As it freezes, it gives off salt, which increases the salinity of the unfrozen water.
Saltier water sinks, helping to drive the ocean currents that carry cold water southward and warm, less saline water northward.
It is this flow of water that helps regulate temperatures around the planet.
When it melts, sea ice is less saline than the ocean water below, so it does not sink. This, some oceanographers fear, could shut down the ocean currents.
If that happens, the Polar Regions would become much colder and a new ice age could set in.
But that would not take effect anytime soon. The immediate reality is that polar ice is melting faster than predicted, and this will affect not just Arctic wildlife, but life around the world.
Ocean levels are rising. They will rise faster as ice continues to melt. This, in turn, will inundate coastal areas that are now dry land.
During the Miocene, ocean levels were higher than they are today. Vast areas of New Jersey, the Delmarva Peninsula, and lands around the Chesapeake and Delaware Bays were under water.
The alarming news from the Arctic means those conditions are likely to return, perhaps within this century.

Relief from the heat

Late August is when the first cold front worthy of the name rolls through, bringing temporary relief from summer heat. One front passed through earlier in the week and another today (Friday). While temperatures have not dropped a lot, they have receded from the upper 90s and lower 100s from just a few weeks ago. The fronts also tell us that autumn, and somewhat cooler temperatures, are coming. It will still get warm, but not oppressively hot for a prolonged period.

The outlook for autumn is for warmer than normal temperatures to continue as the La Nina pattern in the equatorial Pacific continues into winter.

The flipping polarity

Adventures on Earth for August 18, 2010 edition
The latest issue of Earth Magazine examines the issue of the Earth’s magnetic field reversing. The magnetic field has been weakening, a possible indicator that a change is coming.
The questions for which we have no finite answer are when it will occur and what effects it will have.
The Earth’s magnetic field is caused by differential rotation of the solid iron inner core and the molten iron outer core.
There are four zones in our home planet, the solid iron inner core, the molten iron outer core, the viscous rock mantle, and the crustal surface.
The differential rotation of the two inner iron cores acts like a dynamo, putting out a magnetic field that envelops the planet.
The interaction of solar wind with the magnetic field is responsible for the aurorae that dance over polar skies.
Over time the polarity of the magnetic field has changed. The periods between changes vary, so there is no certain time measure.
The polarity flips were revealed when scientists began exploring the issue of plate tectonics, the movement of solid continents on a bed of viscous rock of the mantle.
On either side of the Mid-Atlantic Ridge, where new seabed oozes out, the polarity flips show up as bands.
When molten rock comes to the surface (or to the seafloor), the polarity in effect at that time locks the magnetism of the rock in place. To sort out when flips have occurred, scientists measure the alternating bands and date the rock.
The last reversal took place some 780,000 years ago, a time before humans arrived on the scene. So we don’t know exactly what takes place during the reversal process.
What we do know is that the process can play out over thousands of years in some cases, or in much shorter periods.
In the past, reversals have occurred in relatively rapid bursts, alternating with long periods of quiescence when nothing happens. The current period is apparently one of those long periods of quiescence.
Still, the polarity varies within that long period. We know that magnetic north moves across northern Canada. The movement of the pole requires those navigating by compass to adjust their compasses to magnetic north accordingly. The difference between magnetic north and true north is known as declination.
The magnetic field protects the planet from solar wind. As the magnetic field weakens preceding a polarity flip, there is concern that the loss or weakening of the magnetic will allow solar wind to reach the surface of the planet.
In the past, however, we do not see negative effects on life because of polarity flips. But we live in a highly technical world that can be affected by solar wind. Solar flares can disrupt radio communications, satellites, and shut down power grids.
What will happen and when it will happen remain unknown, but the reversal will happen. Until then, there is time for engineers to study ways to protect against solar wind effects on our technology.

The busiest part of tropical storm season

We enter the busiest time of tropical storm season this weekend. To date there have been three named storms: Hurricane Alex, Tropical Storm Bonnie, and Tropical Storm Colin.

Alex and Bonnie formed in the Gulf of Mexico. Colin formed south of the Cape Verde Islands off the coast of Africa and curled northward. It dissipated near Bermuda.

Sea surface temperatures in the tropical Atlantic and the Gulf of Mexico are warm enough for tropical storm formation as we head into the busy season of what forecasters say will be a heavy year for Atlantic storms.

Warming or cooling

Adventures on Earth for August 11, 2010
By George E. Beetham Jr.
Climate change has been in the news now for several decades. It has been an issue on the planet for roughly 4.6 billion years.
At various times in Earth’s past, the climate has ranged from glacial to tropical. In addition, as continental land masses move around the globe their path takes them through a range of climatic conditions.
As they say, the one constant in the history of Earth has been change.
Change can occur over hundreds of millions of years or it can occur in an instant. The building and erosion of mountains is a slow process that transcends the lives of humans. In contrast, a flood can scour a valley in a matter of hours or an explosive eruption can blow the top off a volcano is mere minutes.
Climate change occurs for many reasons, not all of which are understood. Areas that were once tropical rain forest have become desert and vice-versa. Old seafloor was lifted to form the backbone of Antarctica.
In decades, ocean currents can shut down and plunge a continent into an ice age. In mere seconds, an asteroid can impact Earth and cause widespread extinction.
Recent climate change, though, can be traced to us – humans. Investigators noticed that warming began to increase about the time the industrial revolution and burning fossil fuels began.
As time went by burning of fossil fuels increased. So did planetary warming.
Scientists singled out fossil fuels because the process gives off what are known as greenhouse gases: carbon dioxide, water vapor, nitrous oxide, methane, and ozone are the best known.
These gases tend to seal in heat that otherwise would escape into space, making the Earth warmer just as the glass of a greenhouse seals in heat and creates a rainforest atmosphere in the depth of winter.
At the same time, emission of greenhouse gases under natural conditions, notably volcanic eruptions, has remained fairly constant.
So, while the planet has been in a warming phase since the retreat of the last glaciation some 11,000 years ago, the warming trend made an upward curve in the past 200 years. And remarkably, it was about 200 years ago that anthracite became the fuel of choice in American industry.
Then came the discovery of oil and the dawn of the automotive and air age. Internal combustion engines brought another jump in global warming.
The question we face now is whether we have already reached a tipping point where rapid warming is inevitable or whether there is still time to slow it down.
Regardless of what we do, the fact is that warming will continue. Whether we can rein in warming in time for our children to enjoy the lifestyle we now have is the question.
On the other hand, warming melts glaciers, injecting fresh water into the saline sea. Scientists think that could shut down the ocean currents that now moderate temperatures and bring on a new ice age.
And that change, should it come, could come rapidly.

Auroras and blackouts

Adventures on Earth for August 4, 2010
By George E. Beetham Jr.

A solar flare was expected to reach Earth on Tuesday of this week, perhaps interrupting radio communications and communications satellites and providing spectacular auroral displays at the poles.


The immediate reaction to internet users to the report was concern that the solar flare might pose a danger to life on Earth.

The answer to that question is that solar flares have been erupting in our sun and flying to Earth for the 4.6 billion years our planet has existed.

The only danger, so far as we can tell, would be shortwave radio users bruising their fists pounding on their radios or people in the Arctic and Antarctic straining necks watching the aurora.

How widespread the aurora would be was anybody’s guess when the story broke on Monday. The Geophysical Institute at the University of Alaska Fairbanks forecasts aurora activity, but no report was available for the first three days of August.

There was a slight chance that aurora would be visible in this region, but cloudy skies likely prevented that.

In any event, city lights would have blacked out any aurora that might have been visible from this latitude.

When the sun gives off energy in flares or other ejections, the energy flows outward from the sun. When it reaches Earth, the energy interacts with the planet’s magnetic field.

The aurora is the magnetic field after it is excited by the solar wind.

What we learn from the aurora is that the magnetic field is not static. It ebbs and flows, like ocean waves or wind. The curtains of light shimmer and pulse, sometimes slowly, sometimes more rapidly.

Depending on what matter is carried to Earth from the sun, the aurora can take on colors. Often the aurora is a whitish haze, perhaps with a tint of green.

The aurora are one of nature’s most spectacular displays, particularly when they are more active. As far as the planet is concerned, it is just another day. It has been going on for a long, long time, and it is likely to continue for another long, long time.

Wherever aurora are visible, city lights likely prevent in-town viewing. One has to travel to a dark, rural area to see aurora. Mountaintops are another good place.

Radio communications often black out during solar activity. The ejections excite the radio spectrum, particularly the part of the spectrum used for long-range radio (shortwaves and VHF frequencies).

Often, east-west communications are completely blocked while north-south communications continue unaffected. It’s another geophysical mystery why this is so.

The blockage usually lasts for 24 hours or less and the airwaves return to normal after everything settles down. Blockages can be a minor annoyance or a major problem, depending on how much of the spectrum is affected and what services use those frequencies.

Ham radio operators may want to take a night off, perhaps drive out of town to see if they can catch a view of the aurora.

If you miss it, there are videos of aurora displays all over the internet.