The Triton

Deck

Sea Science: Mirages taunt our inability to discern nature’s tricks

ADVERTISEMENT

Sea Science: by Jordanna Sheermohamed

Seeing is believing, and a human’s ability to observe with our eyes often dictates what we accept as truth. There are times, however, when observations can deceive the mind, playing on the eye’s limited abilities. Optical illusions, such as mirages, have been woven into historical accounts of visions on the ocean or in the deserts, sometimes leading sailors to their unfortunate demise.

Mirages occur when light travels through air masses of different temperatures and, therefore, densities. The light will ultimately bend toward the colder air, which is denser than warmer air because it contains more molecules in a given space. As the light enters and travels through the different layers, it takes multiple paths to the observer, and therefore may produce two images. Because the human eye generally perceives light to move in a direct line, the brain has a hard time distinguishing the optical illusion as being nonexistent.

Mirages can be further classified by the orientation of the air temperature. For instance, inferior mirages, also known as downward mirages, refer to the fact that the mirage appears below the actual object. This happens because the light passes through an unstable column of air, meaning colder air aloft and warmer air at the surface. This forces the light to bend upward, producing an image below the object. The manifestation of water in the hot and dry desert is a well-known result of this scenario, in which excessive sunlight heats the ground, producing the uneven temperature column. The even more common roadway shimmer seen on highways is also a type of inferior mirage.

Fata Morgana mirages create a changing image, which can appear vertically stacked, inverted, or even a series.

A second type of mirage is known as a superior mirage, also called an upward mirage. The name is due to the bending light that displays the mirage above the object’s actual location. The sunlight passes through a warmer layer of air before entering into a relatively cooler layer of air near the surface. This forces the light to bend downward, producing the upward image.  Superior mirage appearances generally occur near cold or icy landmasses and ocean surfaces.  Tales of ghost ships and floating cities are examples of superior mirages, which are the most often type seen on the sea.

One of the most complex type of mirages, the notable “Fata Morgana,” forms as a result of several variations of air temperatures. This forces the light to bend multiple times on its downward trajectory, creating a rapidly changing image, which can appear vertically stacked, inverted, or even a series of the same object.

Other optical phenomena, such as rainbows, auroras, moon bows, and green flashes, also offer up beautiful reminders of atmospheric powers, but none as confusing and mysterious as the mirages that taunt our ability to discern reality from trickery.

Jordanna Sheermohamed is president and lead meteorologist of Weather Forecast Solutions, a weather-forecasting firm (WeatherForecastSolutions.com).  Comments are welcome below.

About Jordanna Sheermohamed

Jordanna Sheermohamed is president and lead meteorologist of Weather Forecast Solutions, a private weather-forecasting company (www.WeatherForecastSolutions.com). Comments are welcome at editor@the-triton.com.

View all posts by Jordanna Sheermohamed →

Related Articles

London’s SKD Marina joins IGY

London’s SKD Marina joins IGY

St. Katharine Docks Marina in London is now a member of the IGY marina destination network, making it the network’s 18th marina across 11 countries, according to an IGY press release. As of …

Crew reviews Below Deck

‘Below Deck’ may be TV, but it’s not reality in yachtingSorry, but this has turned into another pre-scripted drama zone show rather than a real show about yachting life. No …

Westport launches new 112

Westport launches new 112

Westport has launched hull No. 55 in its 112-foot series to a repeat 112 client. In early October, the yacht was en route to Ft. Lauderdale. Westport builds yachts of 112-164 feet in three yards in …

Joe V’s relocates

Joe V’s Yacht Refinishing has relocated into a new 5,000-square-foot Fort Lauderdale location. Growing from two staff in a 1,500-square-foot facility off Andrews Avenue, the company now employs …

MarineMax Vacations opens BVI base

MarineMax Vacations opens BVI base

MarineMax Vacations has opened a base at Nanny Cay on the island of Tortola in the British Virgin Islands. According to the company, the base was specifically built for MarineMax Vacations and the …

Triton Expo vendor photos October 2016

Triton Expo vendor photos October 2016

Click here to see video of the 2016 October Triton Expo

Comments

Leave a comment

Your email address will not be published. Required fields are marked *

Please answer the question below to leave a comment. * Time limit is exhausted. Please reload CAPTCHA.

This site uses Akismet to reduce spam. Learn how your comment data is processed.