changing with the tides

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The vertical difference between high and low tide is called the tidal range. Each month, the range changes in a regular pattern as a result of the sun’s gravitational force on the Earth. Although the sun is almost 390 times farther away from the Earth than is the moon, its high mass still affects the tides. Perhaps the biggest challenge is how changing tides might add to the risks of sea level rise. As people burn more fossil fuels and put more heat-trapping greenhouse gases into the atmosphere, global warming is melting ice caps and causing the volume of the oceans to expand. In many coastal cities, seawater is now lapping higher than it ever has. Changing tides could add to that problem and leave some coasts at even greater risk of flooding. “What people don’t realize is that if tidal range is increasing, it will exacerbate that even more,” says Ivan Haigh, an oceanographer at the University of Southampton, UK. Tides of history Twice each month, the moon lines up with the Earth and sun. These are called the new moon and the full moon. When the moon is between the Earth and the sun, it is in the sun’s shadow and appears dark. This is the new moon. When the Earth is between the sun and moon, the moon reflects sunlight. This is the full moon. There are three different types of tidal power. All of these use tidal energy generators to convert that power into electricity for use in homes and industry. Rising and ebbing tides happen as Earth’s landmasses rotate through the tidal bulges created by the Moon’s gravitational pull. Our observer sees the tides rise when passing through the bulges, and fall when passing through the low points. Of course, in reality the Earth isn’t a smooth ball, so tides are also affected by the presence of continents, the shape of the Earth, the depth of the ocean in different locations, and more. The timing and heights of the tide near you will be affected by those additional elements.

Changing with the Tides | Book by Shelby Leigh | Official

I feel my body and mind are disconnected, except when my worries wage against me and I stay up all night concerned over past transgressions and burden with future bad decisions that have not happened yet. Because of the tidal force, the water on the side of the moon always wants to bulge out toward the moon. This bulge is what we call a high tide. As your part of the Earth rotates into this bulge of water, you might experience a high tide. Perhaps most importantly, engineers can analyze changing tides to better plan for future sea level rise. One recent study looked at the low-lying Pearl River Delta in southern China, which is home to more than 60 million people. Michela De Dominicis, an oceanographer at the National Oceanography Centre in Liverpool, UK, and her colleagues calculated how much tidal ranges would shift for a variety of future scenarios of sea level rise. If the moon's gravity is pulling the oceans toward it, how can the ocean also bulge on the side of Earth away from the moon? It does seem a little weird. It's all because the tidal force is a differential force—meaning that it comes from differences in gravity over Earth's surface. Here's how it works:In the period between the two spring tides, the moon faces the Earth at a right angle to the sun. When this happens, the pull of the sun and the moon are weak. This causes tides that are lower than usual. These tides are known as neap tides.

Changing with the tides: Fine-scale larval fish prey Changing with the tides: Fine-scale larval fish prey

I had always assumed tides were constant,” says Talke, now an oceanographer at California Polytechnic State University in San Luis Obispo. “That’s why we have tide tables.” He was amazed to discover, he says, that not only could tides undergo long-term changes, but that they could change by so much. Twice a month, when the sun, the moon and Earth are nearly in alignment, Earth experiences “spring” tides. During these periods high tides are a little higher than usual and low tides are a little lower than usual. Seven days after spring tides, when the sun and the moon are at right angles to each other, their gravitational tugs partly cancel each other out, resulting in moderate “neap” tides. One high tide always faces the moon, while the other faces away from it. Between these high tides are areas of lower water levels—low tides. The flow of water from high tide to low tide is called an ebb tide. The way the water moves across the basin is changing, which is having quite a profound effect on the tides,” he says. On the side of Earth that is directly facing the moon, the moon's gravitational pull is the strongest. The water on that side is pulled strongly in the direction of the moon.The Sun causes tides just like the moon does, although they are somewhat smaller. When the earth, moon, and Sun line up—which happens at times of full moon or new moon—the lunar and solar tides reinforce each other, leading to more extreme tides, called spring tides. When lunar and solar tides act against each other, the result is unusually small tides, called neap tides. There is a new moon or a full moon about every two weeks, so that's how often we see large spring tides. In the open ocean, the tidal force of the moon will appear as bulges of water facing the moon whereas around land mass the water can spread out onto land creating tides. Types of tides One thing to note, however, is that this is just an explanation of the tidal force—not the actual tides. In real life, the Earth isn't a global ocean, covered in an even layer of water. There are seven continents, and that land gets in the way. The continents prevent the water from perfectly following the moon's pull. That's why in some places, the difference between high and low tide isn't very big, and in other places, the difference is drastic. That explains the first high tide each day, but what about the second high tide?

tides they are a-changin’ — and it’s not just from The tides they are a-changin’ — and it’s not just from

That’s why understanding changing tides is crucial to preparing for the future, Talke says. People are going to continue to dredge channels and fill in wetlands and otherwise alter our coastal surroundings. Bit by bit, each modification shifts the world in which we live. “The sum of all the little changes,” Talke says, “turns out to be a really big change.” Twice a month, when the Earth, Sun, and Moon line up, their gravitational power combines to make exceptionally high tides, called spring tides, as well as very low tides where the water has been displaced. When the Sun is at a right angle to the Moon, moderate tides, called neap tides, result. From our view on Earth, these tides coincide with certain lunar phases since they occur when the Moon reaches specific positions in its orbit. Changing tides affect coastal residents in many ways. Someone who wants to sail a tall ship under a short bridge has to wait for just the right tidal conditions while anyone who wants to build a riverfront home in an estuary has to know exactly where the high-tide mark is. Engineers designing a tidal-energy system need to know how much energy they can extract from the water flows. And that’s where the study of changing tides can help people prepare for a changing world. Researchers are also using computer models to analyze how changing tides and rising sea levels might affect other types of coastal flooding. A hurricane’s storm surge, for instance, often responds to the changing landscape much as tides do. In a 2016 study, Talke and Ramin Familkhalili of Portland State analyzed how storm surge might change in the Cape Fear River estuary along with the changing tides.changing with the tides is one of those poetry collections that speaks to those who have always seen softness and strength as synonymous. Shelby's ability to write about emotional trauma with such delicacy is truly remarkable. Her sensitivity comes through in every word—making the reader feel like Shelby isn't only sharing her own personal experiences but is being mindful of the reader's comfort. I highly recommend this book to anyone who is coping with anxiety or looking for some healing words without having to read something heavy. Thank you, Shelby, for striking such a graceful balance with your poetry.” —Marya Layth, author of Driftwood Twice a month, the difference between high tide and low tide is at its smallest. These tides are called neap tides. To keep with the ocean aesthetic (and because this is just what I envision when I think of the book as a whole), I have the image of waves.