Archive for September 2015

Oceanic introduces Veo-100-nx

Those looking for a full-featured entry level Air or Nitrox Dive Computer will love Oceanic’s new Veo 100 Nx, announced today.

Oceanic Introduces the Veo 100 Nx

image-124-Oceanic Veo 100 Nx 0

Those looking for a full-featured entry level Air or Nitrox Dive Computer will love Oceanic’s new Veo 100 Nx, announced today. The Veo 100 Nx is the next generation of the popular Veo 100. “The Veo 100 has been extremely successful as an entry level, back-up or rental computer due to competitive pricing, ease of use and reliability.” said Doug Krause, Marketing Manager for Oceanic Worldwide. “The addition of Nitrox with the launch of the Nx will no doubt further strengthen our dominant market share in this category.”

Key features of the new Veo 100 Nx include:

  • Air and Nitrox Operating Modes

  • Easy to learn and use

  • Customize the information displayed during a dive with a press of a button

  • “Hockey Puck” module is the same size as most depth gauges for easy and inexpensive console upgrades

  • Water activation

  • Reset feature for rental/charter applications

  • Diver-replaceable battery with Hot Swap memory allows battery change between dives

  • Automatic Safety Stop Prompt

  • 12 Dive Log Book

In addition, the Veo 100 Nx offers several user settings and options including Nitrox 21– 50%, Maximum PO2 (1.2 – 1.6), FO2 50% Default (ON / OFF), Water Activation (ON / OFF), Units of Measure (Imperial / Metric), Hour Format (12 / 24), and Time of Day.

Source: http://www.sportdiver.com/article/news/oceanic-introduces-veo-100-nx?src=related&con=outbrain&obref=obnetwork

Posted Wednesday, 30 September 2015 by Culebra Snorkeling and Dive Center in Culebra Posts & Reviews

Culebra Snorkel or Dive ?

 

Snorkeling is also known as free-diving: Strap on a mask, snorkel, and fins you’ll be ready to quite literally pass through the looking-glass into another world. The warm waters of Culebra will embraces your body and frees you from gravity, allowing you to fly among the parrots, butterflies, angels, damsels, and, turtles then dance with the hamlets and scarlet ladies, and bow to the barracuda and dolphin.

The tropical sea covers an unrestricted collection of life. And one of our greatest attractions is that you can wade into the water off any point of land and find yourself immersed in a universe of outrageous color and interesting characters. Of course it’s always better off a picture perfect gorgeous beach … or one with nothing but solitude and sand.

And whether you’re just looking for a calm swim with friendly fish or a synchronized float with your significant other, we will help you found your perfect Caribbean beach. A day of snorkeling or diving on Culebra that focuses first on safely reaching the best waters for the conditions in the Culebra area, will ensure splashing among thickets of Elkhorn, Staghorn, and Pillar coral, while poking into shallow caves and overhangs that dance with tropical fish of every color and persuasion.

The clear blue skies highlights Culebra’s bleach-white beaches, transparent turquoise water and luxuriant reefs, all of which are among the very best in the Caribbean. Flamenco Beach, on the north side, is the best stretch of sand on the island, which boasts some 2 miles of sink-to-your-ankles, soft-coral-sand beach.  Not to take away from the other snorkeling, diving, kayaking, and paddle boarding sites Culebra can offer (over 20) with proper directions are just a short walk, hike, or drive.

The west end of Culebra is protected from the Caribbean’s north eastern swells and has a shoreline reef system that opens to sandy encased shallow lagoons,  The shoreline reef system extends out from the beach to honeycombed depths of 10-60ft thick then drop off to sandy flats simply keeping the sea life close which is perfect for snorkeling. Just under the surface, hemostat-jawed needlefish, yellow tail snapper, spanish grunts, and various grouper stalk silvery blankets of minnows while cobalt clouds of blue tang swarm over boulders of brain coral, leisurely picking at tufts of algae. Fish, lobsters, stingrays, turtles, ells, and crabs fill every nook and cranny of the reef.

Source: Culebra Snorkel or Dive ?

Posted Saturday, 26 September 2015 by Culebra Snorkeling and Dive Center in Culebra Posts & Reviews

Gear / How to Maintain Your Snorkel / Dive Mask

Gear Basic – Mask Maintenance

Critical scuba diving gear requires annual inspection and service by a qualified technician, but even dive masks — your window to the underwater world — need some special TLC. Here’s our guide to keeping your mask in tiptop shape in 5 easy steps.

Predive
1. If you haven’t replaced your mask strap with a stretchy fabric one, stretch out the strap to look for fine cracks. If you do find any, immediately replace the strap.
2. Examine the silicone of your mask skirt. The most common failure area on a mask is the feather-edged seal on the skirt. This can become imperfect or irregular in shape with time and heavy use, and that irregularity can create leaks.
3. Check all the buckles, which can crack, split or become clogged with debris that can interfere with how they function. Then check the frame of your mask for cracking, chips or other obvious signs of wear, especially in the areas immediately adjacent to the glass lens.

Postdive
1. To avoid mildew growth, rinse your mask in warm, fresh water and allow it to drip dry completely before packing it away.
2. Pack the mask loosely, so nothing distorts the mask skirt. Leaving it squashed into a weird position for a long period of time will cause it to take on an unnatural shape.

Source: Gear / Masks | Sport Diver

15 Tips for Avoiding Seasickness | Sport Diver

Why do scuba divers get motion sickness? It’s because your feet are telling your brain that you’re on solid ground, but you’re really rocking and rolling on the high seas. Your brain gets confused; you get sick.

Anyone who’s ever tried to keep their cookies settled while riding on a turbulent sea knows Kermit speaks the truth: It’s not easy being green. But it’s the rare ocean traveler who’s never turned the sickly shade. Nearly 100 percent of boat passengers will experience some level of seasickness on rough waters, says the Centers for Disease Control, and some of us seem to get green around the gills 100 percent of the time, regardless of the motion of the ocean.

If you’re one of the unlucky 100 percent, you can blame your parents, as it’s likely genetic. Fortunately, you don’t have to abandon ship. Motion sickness and the many factors that affect it can be largely controlled. Here’s how:

• Look up and out. At the most basic level, seasickness is a matter of sensory mismatch. When you’re sitting on a boat that’s rolling on the water, the body, inner ear and eyes all send different signals to the brain. Your brain gets confused and you get queasy. Stop tinkering with your computer and equipment and look out on the horizon, which usually appears very stable. Your peripheral vision will see the ocean swells that you feel. The whole picture will make more sense to your brain. Likewise brace yourself at the center of the boat where the rocking and rolling is less amplified.

• Tame your tummy. Have a Coke. It contains phosphoric acid and sugars, the same ingredients you’ll find in Emetrol, an over-the-counter anti-nausea drug.

• Apply some pressure. For centuries, traditional Chinese medicine has included acupuncture or acupressure on the inside of the wrist, at a spot called P6, as a way to suppress the nausea associated with motion sickness. You can find simple pressure bands like Sea-Band and Acuband at your local drug store. More sophisticated, battery-operated bands like Reliefband, which delivers an electrical pulse instead of pressure, are out there as well.

• Pop a pill. Meds like Dramamine, Bonine and even antihistamines like Benadryl can help quell motion sickness by blocking sensory-nerve transmission, which is a fancy way of saying they interrupt the flow of information from various places like the middle ear (involved in balance) to the brain. They can cause drowsiness and fuzzy thinking, however, so definitely take them for a test drive before diving on them. All the pills are about the same in effectiveness and side effects. But if one of them—Dramamine, Bonine, Marazine, etc.—seems to work better for you than the others, stick with it. The placebo effect is very strong with seasickness. And start taking the medication early: Pills are better prevention than treatment. After you feel queasy, it may be too late for pills to help, so start 12 to 24 hours before going to sea. This builds up a level of the drug in your body.

• Try wearing an anti-nausea band. Some people like “Sea Bands.” They are bracelets with dots that purportedly touch acupressure points on your wrist. They have never been proven effective, but some people swear by them.

• Wear a patch. Scopolamine, a drug that reduces the activity of nerve fibers in your inner ear, is hands down the most successful commercial seasickness medication on the market. You get a steady dose by wearing a medicated patch like the Transderm Scop patch behind your ear. Just be mindful of following directions and watching for side effects like dry mouth and blurred vision.

• Don’t try to read. Focusing your eyes on an apparently stationary target makes them even more convinced that your middle ears are wrong.

• Close your eyes. You may have to go below or find a place to stretch out and lie down, in which case you should close your eyes so they aren’t giving a no-motion message to your brain.

• Be clean and sober. Even a mild hangover can easily degenerate into seasickness, besides increasing various diving risks. Likewise, fatigue predisposes you to seasickness.

• Eat something. Opinions vary on this one, but most people feel better with a little bland food on their stomachs. Bread, bagels, pancakes, etc. are better than eggs and bacon. Coffee and orange juice are acidic and may irritate your stomach. Eat a little, not a lot.

• Relax. Anxiety contributes to seasickness. Those who are frightened by the ocean and the movement of the boat, or anxious about the diving later in the day, are more likely to become seasick.

• Watch for symptoms. Early signs include chills, headache and frequent burping. Now is the time to go on deck, or move to the lee rail if you’re already there.

• Plan ahead. All of these techniques work best if you apply them before you need them — to prevent getting motion sick in the first place. So take precautions early.

I’M SEASICK: NOW WHAT?

• If you feel the urge, let it rip. You’ll feel better almost immediately. Prolonging the inevitable only prolongs the pain.

• Don’t use a toilet. Or, God help us, a trash can. Go to the rail on the lee (downwind) side or use a bucket if one is designated. If you feel the urge coming, ask a crew member where to go. He or she will know the best place. Don’t be embarrassed; you’re not the first.

After a few hours, most people feel better. For some it takes a day or two. Almost everyone gets over seasickness within three days.

Source: 15 Tips for Avoiding Seasickness | Sport Diver

Underwater Photo Tips: Capturing People

People can be among the trickiest subjects for underwater photography. Learn from the pros with these simple tips, and bring out the best from your dive photos.

Few underwater photographers start out wanting to photograph people. Our first shots are usually to record all the fish and marine life that got us diving in the first place. We might take the occasional snaps of our buddies, but new photographers are rarely motivated to take people pics.

That all changes when you start showing your images, wanting to tell stories with them, and trying to get them published. In these cases, people shots are invaluable. In short, if you want your photos to sell, the most important subject that you can point your camera toward is another diver.

Magazines love people pictures because a model adds human interest, helps tell a story and endows an image with the sense of “that could be me.” Pho- tographically, a model provides a sense of scale, which can balance a wide-angle composition, creating a point of interest in otherwise open water, and by looking at the main subject of the photo, can reinforce the viewer’s interest, helping your composition work.

In theory, people should be one of the easiest underwater subjects. They are big, won’t run away and will even pose on demand. However, there are a few small details to help ensure that your model shots stand out.

Model Behavior

The first challenge of people photography is finding someone willing to pose. Distant compositions can be made with passing divers, also known as models of opportunity, but most people pictures require planned posing. Many photog- raphers dive together and take turns modeling for each other.

The best divers are usually the best models, because they look the most relaxed in the water and can most easily hold an elegant pose. Dive guides are ideal, but their time is not only yours, and they will have more-important responsibilities to tend to.

I often ask staff on their days off, who will usually be happy to have some photos to share with their family and friends. (It doesn’t hurt that they are usually better proportioned than your average vacationer — or underwater photographer for that matter!)

People work best in underwater pictures when they are either near or far. Middle distance is rarely effective because the model is too far away to be lit effectively and still too large in the frame to balance the composition in the way that a distant silhouette does.

Keep Your Distance

Before diving, I discuss my plans and show the models how wide a view my fisheye lens sees, so they understand how they will appear. When working with new models, I’ll start off framing them as a silhouette, which makes them less self-conscious and more relaxed. And since their eyes are not visible, they can look right at me and judge their position from the reflection in my dome port. As a silhouette, the diver’s shape is critical to an engaging composition. Even small in the frame and clad in neoprene, viewers will still pick up on body language.

The best pose might take a few shots to perfect, so make sure you’ve got the rest of the picture right before calling in a model. It is also easier for a model to swim than to hover, so advise your model to fin across your picture, parallel to the camera. If he swims straight at you, his silhouette will be a messy blob. What also looks bad: perfect tec-diver trim, with knees bent up, frog kicks and hands thrust out in front. Neat arms and long, straight legs look much more elegant — better still if one leg is slightly bent, so the diver looks like he is swimming.

Look in the Eye

When a diver is close and lit well, his eyes will dominate the composition. Glance across the page, and you’ll find that the model’s eyes grab your attention, despite being small. Getting the eyes right becomes critical to the success or failure of the image.

Lighting a diver’s eyes is much easier with a clear-skirted mask because clear silicone lets in the light from your strobes, while a black-skirted mask is more likely to cast shadows. Most flattering is a 1960s oval mask, which shows the entire face. But, of course, nobody uses these masks anymore, and many editors will instantly reject your photos as dated.

The best directions to give a model are to face toward the camera but not to look straight into the lens in a “Hi, Mom!” pose. If there is subject matter between you and the model, you can direct the model to look at that subject. If not, ask him to look at your hand, and hold it above and slightly to the side of the camera. But the best advice is to always be patient and encouraging. Modeling is much harder than it looks, so always be grateful to anyone willing to give his or her dive time for your photos.

Pro Tip
A wide-angle lens is a necessity when photographing people, but these types of lenses tend to distort the scene, especially fisheye lenses. Unlike distorted fish photos, photos of misshapen divers can be distracting. Try to avoid placing people close to the corners or edges of the frame so that there are no unwanted bulges. If necessary, use processing software to correct any fisheye distortion.

image-spd0615 images raj13 am-10439

Source: Underwater Photo Tips: Capturing People | Scuba Diving Photography | Sport Diver

Posted Saturday, 26 September 2015 by Culebra Snorkeling and Dive Center in Culebra Posts & Reviews

Storm Surge–Plain and Simple (Part 1)

Source: Storm Surge–Plain and Simple (Part 1)

Storm Surge–Plain and Simple (Part 1)

POSTED ON JUNE 17, 2014

lake2

You may have heard that NHC is unveiling an experimental storm surge graphic this hurricane season.  We mentioned in our first blog post on May 29 that we would be discussing the background and interpretation of this graphic.  There’s a lot to cover, so instead of throwing it all at you in one shot, we are going to do a three-part series on the new graphic and communication on storm surge in general.  Here’s what we plan on covering:

Part 1:  Why do we need a storm surge graphic?

Part 2:  How is the storm surge graphic created?

Part 3:  How should you interpret the storm surge graphic?

High Water Memo

So, let’s get on with Part 1.  First, let’s look back at a little history.  Way back in 1955, the U.S. Weather Bureau issued a memo (figure to the right) to weather offices along the coast, directing them to refer to any water rise produced by a hurricane or tropical storm in terms of “above normal tide levels,” and those rises were to be specified in ranges to account for uncertainty.  Believe it or not, that policy went unchanged for over 50 years!  In 2008, the NHC Public Advisories for Hurricane Ike referred to storm surge like this:

“COASTAL STORM SURGE FLOODING OF UP TO 20 FEET…WITH A FEW SPOTS TO NEAR 25 FEET…ABOVE NORMAL TIDES ALONG WITH LARGE AND DANGEROUS BATTERING WAVES…CAN BE EXPECTED NEAR AND TO THE EAST OF WHERE THE CENTER OF IKE MAKES LANDFALL. THE SURGE EXTENDS A GREATER THAN USUAL DISTANCE FROM THE CENTER DUE TO THE LARGE SIZE OF THE CYCLONE. WATER LEVELS HAVE ALREADY RISEN BY MORE THAN 5 FEET ALONG MUCH OF THE NORTHWESTERN GULF COAST.”

For many years, we didn’t have the technology, nor sufficient accuracy in our track forecasts, to be any more specific in our Public Advisories.  The best we could do was give an estimate of the highest storm surge expected with a general description of where that surge could occur relative to the center of the storm.  Unfortunately, many times these statements were too vague for emergency managers and other decision makers to make sound decisions before a storm.  One question a statement like this could not answer:  “How far inland could the storm surge go?”

Another issue had to do with what are called vertical datums.  We’ll leave the more technical discussion of vertical datums for another blog post, but what you need to know for this discussion is that a vertical datum is simply a reference point.  The water level height caused by the combination of storm surge and the tide must be attached to some point of reference.  The operative question is “the height of the water level is 6 feet above what?”  The problem was that many people either weren’t specifying what the datum was, or they were confusing one datum with another.

Here’s an example, again using Ike, where confusion set in.  The figure below shows output from the National Weather Service SLOSH model indicating simulated water level heights from Hurricane Ike along the Texas and Louisiana coasts.  What’s the first thing that jumps out at you?  The first question many people have is why do the values increase (go from 15 feet to over 21 feet) as you move inland from the coast into Chambers and Jefferson Counties in Texas?  Shouldn’t the deepest water have occurred at the immediate coast?  The subtlety here is that the water level in this picture is depicted relative to a datum called NAVD88.  So, the water levels in Chambers and Jefferson Counties were more than 21 feet above NAVD88, not 21 feet above the actual ground at those locations.

Ike Surge NAVD

Luckily, there’s a way to display how much water was sitting on normally dry ground, which is what most people typically envision when given storm surge heights.  Since we know what the elevation of the land is at each location, relative to the same vertical datum used for the surge data itself, we can subtract the land elevation from the surge heights to get a good idea of how high the water was above the ground at each location.  The next figure is the same simulation for Ike but instead shows this subtraction at play.  Notice any differences from the previous image?

Ike Surge Ground

Now it should all make sense.  The highest values (about 15 feet above ground level) are located along the immediate coast and decrease as you move inland.

Recent hurricanes like Katrina, Rita, and Ike showed that we needed to make some changes in the ways that we communicate storm surge information.  And thankfully, we now have the technologies and capabilities to go beyond simplified text statements in the Public Advisory.  In Part 2 of this series, we’ll talk about the Probabilistic Storm Surge product, how it accounts for uncertainties in the storm surge forecast, and how it is being used to create the Experimental Potential Storm Surge Flooding Map for this hurricane season.

— Robbie Berg and Jamie Rhome

Posted Saturday, 5 September 2015 by Culebra Snorkeling and Dive Center in Culebra Posts & Reviews

The Ups and Downs of Predicting Tropical Cyclone Formation: The Role of Atmospheric Waves

 The Role of Atmospheric Waves

POSTED ON JUNE 25, 2015

A previous blog entry described the new NHC five-day tropical cyclone formation (or genesis) products.  In this blog entry, we discuss the factors that go into these predictions.

The primary tool used at NHC for five-day tropical cyclone genesis forecasts is global numerical modeling.  Global models can predict many of the environmental factors that influence tropical cyclone formation, and the skill of these models has been improving with time.  More tropical cyclone formations are being forecast with longer lead times, and weather prediction models show fewer “false alarms” than in the past.  Recent studies suggest, and forecaster experience seems to confirm, that a consensus of the available model guidance usually outperforms any single model.   This “two heads are better than one” approach works as long as the models (or heads) are somewhat independent of one another.  In addition, NHC is currently evaluating a few statistical techniques that use the global model output to produce objective guidance designed to assist hurricane specialists in developing the probabilities of formation issued in the Tropical Weather Outlook.

Kelvin Waves and the Madden-Julian Oscillation

Global model guidance is not the only tool available to NHC forecasters, however.  Researchers have learned that a majority of lower latitude tropical cyclone formations are associated with waves in the atmosphere moving through the global Tropics from west to east.    Two particularly important wave types are the Convectively Coupled Kelvin Wave (CCKW), which circumnavigates the equator in about 15 to 20 days, and the Madden-Julian Oscillation (MJO), which transits the globe in 30 to 60 days.  These waves are normally initiated by large areas of thunderstorm activity over tropical regions, especially near India and southeastern Asia.  These waves are different in both frequency and direction of motion from the more well-known tropical waves that originate over Africa and often spawn tropical cyclones as they move westward across the Atlantic and eastern North Pacific basins.

Tropical cyclone formation often accompanies the passage of the “active phase” of either the faster-moving CCKWs or the slower-moving MJO.   Figure 1 shows tropical cyclone tracks over a 37-year period in active and inactive phases of the MJO as the wave moves around the globe, along with increased or decreased rainfall anomalies associated with the two phases of the MJO (Zhang 2013).   In the figure, the active phase of the MJO for the Atlantic occurs in panel (a), while for the eastern Pacific the active phase occurs in panel (d).  The less active phases for these two basins fall in panels (c) and (b), respectively.

Figure 1. Tropical cyclone tracks in active and inactive phases of the MJO and increased (green) and decreased (purple) rainfall anomalies associated with the two phases of the MJO (from Zhang 2013). Panel (a) shows the active phase of the MJO for the Atlantic, and (d) shows the active phase for the eastern Pacific. Panels (b) and (c) show the less active phases for both basins.
Figure 1. Tropical cyclone tracks in active and inactive phases of the MJO and increased (green) and decreased (purple) rainfall anomalies associated with the two phases of the MJO (from Zhang 2013). Panel (a) shows the active phase of the MJO for the Atlantic, and (d) shows the active phase for the eastern Pacific. Panels (b) and (c) show the less active phases for both basins.

This concentration of tropical cyclone activity occurs because each type of wave temporarily makes large-scale environmental conditions, such as vertical wind shear or atmospheric moisture, more conducive for tropical cyclone formation.  Although not every wave causes a tropical cyclone to form, pre-existing disturbances have a greater likelihood of developing into tropical cyclones after the passage of a CCKW or the MJO.  High-activity periods can last as long as a week or more with the MJO, but are generally followed by days to possibly weeks of little to no activity during the inactive phases of these waves, when large-scale conditions become unfavorable for tropical cyclone formation.  Forecasters use real-time atmospheric data and other tools to diagnose the location and motion of these important catalysts for tropical cyclone formation.

Here is an example from the 2014 hurricane season of how forecasters used these atmospheric signals.  The graphic below, called a Hovmöeller diagram, shows where large areas of rising air (cool colors) and sinking air (warm colors) exist near the equator as a function of time.  The dashed black contours depict the active phase of successive CCKWs, and the solid red contours show the inactive phases.    In this particular case, forecasters noted that there was a strong CCKW moving through the eastern Pacific in the middle part of October.  Extrapolating the wave forward in time, along with numerical models forecasts of the wave’s location and strength, suggested that a tropical cyclone could form within a few days over the far eastern Pacific from a disturbance that was already in the area.  The green dot indicates where Tropical Storm Trudy formed, a day or two after the CCKW passed the disturbance.  Although CCKW tracking is only a secondary factor in determining a Tropical Weather Outlook forecast, a basic knowledge of this atmospheric phenomenon is an important part of the process.

active inactive phase
Figure 2. Hovmoeller diagram showing large areas of rising air (cool colors) and sinking air (warm colors) near the equator as a function of time

Forecasters consider many factors when preparing the five-day genesis probabilities for the Tropical Weather Outlook, including explicit forecasts from the global models and knowledge of any ongoing CCKWs or the MJO.   In addition, the final NHC forecast also reflects the current trends of the disturbance, which are weighted much more heavily in the two-day outlook, but also can affect the five-day forecast as well.  There are several ongoing research projects that will hopefully yield objective probabilities and other tools designed to help better predict tropical cyclone formation.  These tools, in combination with the dynamical guidance from numerical models, should improve the quality of genesis forecasts and perhaps in the next five years extend reliable tropical cyclone formation forecasts from five days to one week.

— Eric Blake and Todd Kimberlain

Source: The Ups and Downs of Predicting Tropical Cyclone Formation: The Role of Atmospheric Waves

Posted Saturday, 5 September 2015 by Culebra Snorkeling and Dive Center in Culebra Posts & Reviews

Cyclones and Warnings and Names, Oh My!

Source: Cyclones and Warnings and Names, Oh My!

Posted Saturday, 5 September 2015 by Culebra Snorkeling and Dive Center in Culebra Posts & Reviews

%d bloggers like this: