The Power of the Sea
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Wind-Caused Waves Misleads Us Energy Is Transferred to the Wave
WAVES IN WATER is quite similar. Most waves are created by the frictional drag of wind blowing across the water surface. A wave begins as Tsunami can be the most overwhelming of all waves, but a tiny ripple. Once formed, the side of a ripple increases the their origins and behaviors differ from those of the every day waves we see at the seashore or lakeshore. The familiar surface area of water, allowing the wind to push the ripple into waves are caused by wind blowing over the water surface. a higher and higher wave. As a wave gets bigger, more wind Our experience with these wind-caused waves misleads us energy is transferred to the wave. How tall a wave becomes in understanding tsunami. Let us first understand everyday, depends on (1) the velocity of the wind, (2) the duration of wind-caused waves and then contrast them with tsunami. time the wind blows, (3) the length of water surface (fetch) the wind blows across, and (4) the consistency of wind direction. Once waves are formed, their energy pulses can travel thou Wind-Caused Waves sands of kilometers away from the winds that created them. Waves transfer energy away from some disturbance. Waves moving through a water mass cause water particles to rotate in WHY A WIND-BLOWN WAVE BREAKS place, similar to the passage of seismic waves (figure 8.5; see Waves undergo changes when they move into shallow water figure 3.18). You can feel the orbital motion within waves by water with depths less than one-half their wavelength. -
Time and Tides in the Gulf of Maine a Dockside Dialogue Between Two Old Friends
1 Time and Tides in the Gulf of Maine A dockside dialogue between two old friends by David A. Brooks It's impossible to visit Maine's coast and not notice the tides. The twice-daily rise and fall of sea level never fails to impress, especially downeast, toward the Canadian border, where the tidal range can exceed twenty feet. Proceeding northeastward into the Bay of Fundy, the range grows steadily larger, until at the head of the bay, "moon" tides of greater than fifty feet can leave ships wallowing in the mud, awaiting the water's return. My dockside companion, nodding impatiently, interrupts: Yes, yes, but why is this so? Why are the tides so large along the Maine coast, and why does the tidal range increase so dramatically northeastward? Well, my friend, before we address these important questions, we should review some basic facts about the tides. Here, let me sketch a few things that will remind you about our place in the sky. A quiet rumble, as if a dark cloud had suddenly passed overhead. Didn’t expect a physics lesson on this beautiful day. 2 The only physics needed, my friend, you learned as a child, so not to worry. The sketch is a top view, looking down on the earth’s north pole. You see the moon in its monthly orbit, moving in the same direction as the earth’s rotation. And while this is going on, the earth and moon together orbit the distant sun once a year, in about twelve months, right? Got it skippah. -
Moons Phases and Tides
Moon’s Phases and Tides Moon Phases Half of the Moon is always lit up by the sun. As the Moon orbits the Earth, we see different parts of the lighted area. From Earth, the lit portion we see of the moon waxes (grows) and wanes (shrinks). The revolution of the Moon around the Earth makes the Moon look as if it is changing shape in the sky The Moon passes through four major shapes during a cycle that repeats itself every 29.5 days. The phases always follow one another in the same order: New moon Waxing Crescent First quarter Waxing Gibbous Full moon Waning Gibbous Third (last) Quarter Waning Crescent • IF LIT FROM THE RIGHT, IT IS WAXING OR GROWING • IF DARKENING FROM THE RIGHT, IT IS WANING (SHRINKING) Tides • The Moon's gravitational pull on the Earth cause the seas and oceans to rise and fall in an endless cycle of low and high tides. • Much of the Earth's shoreline life depends on the tides. – Crabs, starfish, mussels, barnacles, etc. – Tides caused by the Moon • The Earth's tides are caused by the gravitational pull of the Moon. • The Earth bulges slightly both toward and away from the Moon. -As the Earth rotates daily, the bulges move across the Earth. • The moon pulls strongly on the water on the side of Earth closest to the moon, causing the water to bulge. • It also pulls less strongly on Earth and on the water on the far side of Earth, which results in tides. What causes tides? • Tides are the rise and fall of ocean water. -
Tsunami, Seiches, and Tides Key Ideas Seiches
Tsunami, Seiches, And Tides Key Ideas l The wavelengths of tsunami, seiches and tides are so great that they always behave as shallow-water waves. l Because wave speed is proportional to wavelength, these waves move rapidly through the water. l A seiche is a pendulum-like rocking of water in a basin. l Tsunami are caused by displacement of water by forces that cause earthquakes, by landslides, by eruptions or by asteroid impacts. l Tides are caused by the gravitational attraction of the sun and the moon, by inertia, and by basin resonance. 1 Seiches What are the characteristics of a seiche? Water rocking back and forth at a specific resonant frequency in a confined area is a seiche. Seiches are also called standing waves. The node is the position in a standing wave where water moves sideways, but does not rise or fall. 2 1 Seiches A seiche in Lake Geneva. The blue line represents the hypothetical whole wave of which the seiche is a part. 3 Tsunami and Seismic Sea Waves Tsunami are long-wavelength, shallow-water, progressive waves caused by the rapid displacement of ocean water. Tsunami generated by the vertical movement of earth along faults are seismic sea waves. What else can generate tsunami? llandslides licebergs falling from glaciers lvolcanic eruptions lother direct displacements of the water surface 4 2 Tsunami and Seismic Sea Waves A tsunami, which occurred in 1946, was generated by a rupture along a submerged fault. The tsunami traveled at speeds of 212 meters per second. 5 Tsunami Speed How can the speed of a tsunami be calculated? Remember, because tsunami have extremely long wavelengths, they always behave as shallow water waves. -
Tsunamis in Alaska
Tsunami What is a Tsunami? A tsunami is a series of traveling waves in water that are generated by violent vertical displacement of the water surface. Tsunamis travel up to 500 mph across deep water away from their generation zone. Over the deep ocean, there may be very little displacement of the water surface; but since the wave encompasses the depth of the water column, wave amplitude will increase dramatically as it encounters shallow coastal waters. In many cases, a El Niño tsunami wave appears like an endlessly onrushing tide which forces its way around through any obstacle. The image on the left illustrates how the amplitude of a tsunami wave increases as it moves from the deep ocean water to the shallow coast. Over deep water, the wave length is long, and the wave velocity is very fast. By the time the wave reaches the coast, wave length decreases quickly and wave speed slows dramatically. As this takes place, wave height builds up as it prepares to inundate the shore. Why do Tsunamis occur in Alaska? Subduction-zone mega-thrust earthquakes, the most powerful earthquakes in the world, can produce tsunamis through fault boundary rupture, deformation of an overlying plate, and landslides induced by the earthquake (IRIS, 2016). Megathrust earthquakes occur along subduction zones, such as those found along the ring of fire (see image to the right). The ring of fire extends northward along the coast of western North America, then arcs westward along the southern side of the Aleutians, before curving southwest along the coast of Asia. -
Ahead of the Wave
sciencenewsf o rkids.o rg http://www.sciencenewsforkids.org/2013/02/scientists-are-working-to-predict-and-tame-the-tsunamis-that-can-threaten-some- coastal-communities/ Ahead of the wave By Stephen Ornes / February 13, 2013 Bump a glass and any water inside might slop over the side. Splash in the bathtub and waves slosh. Toss a rock into a pond and ripples move outward in expanding rings. In each case, the water moves in waves. Those waves carry energy. And the more energy that gets added to a watery environment, the more powerf ul the waves may become. Now imagine an undersea earthquake and the tremendous amount of energy it can transf er to the ocean. That is because the movement of the Earth’s crust can shif t huge volumes of water, unleashing a parade of great and powerf ul waves. The water races away at speeds up to 800 kilometers (500 miles) per hour, or as f ast as a jet plane. Eventually those waves reach shallow Wate r p o urs asho re as a tsunami strike s the e ast co ast o f Jap an o n March 11, 2011. Cre d it: Mainichi Shimb un/Re ute rs water. They slow down and swell, sometimes as high as a 10-story building. When the waves eventually crash onto land, they can swamp hundreds of kilometers (miles) of shoreline. They may snap trees like twigs, collapse of f ice buildings and sweep away cars. Among nature’s most powerf ul f orces of destruction, these waves are called tsunamis (tzu NAAM eez). -
Documenting Inuit Knowledge of Coastal Oceanography in Nunatsiavut
Respecting ontology: Documenting Inuit knowledge of coastal oceanography in Nunatsiavut By Breanna Bishop Submitted in partial fulfillment of the requirements for the degree of Master of Marine Management at Dalhousie University Halifax, Nova Scotia December 2019 © Breanna Bishop, 2019 Table of Contents List of Tables and Figures ............................................................................................................ iv Abstract ............................................................................................................................................ v Acknowledgements ........................................................................................................................ vi Chapter 1: Introduction ............................................................................................................... 1 1.1 Management Problem ...................................................................................................................... 4 1.1.1 Research aim and objectives ........................................................................................................................ 5 Chapter 2: Context ....................................................................................................................... 7 2.1 Oceanographic context for Nunatsiavut ......................................................................................... 7 2.3 Inuit knowledge in Nunatsiavut decision making ......................................................................... -
SPH Based Shallow Water Simulation
Workshop on Virtual Reality Interaction and Physical Simulation VRIPHYS (2011) J. Bender, K. Erleben, and E. Galin (Editors) SPH Based Shallow Water Simulation Barbara Solenthaler1 Peter Bucher1 Nuttapong Chentanez2 Matthias Müller2 Markus Gross1 1ETH Zurich 2NVIDIA PhysX Research Abstract We present an efficient method that uses particles to solve the 2D shallow water equations. These equations describe the dynamics of a body of water represented by a height field. Instead of storing the surface heights using uniform grid cells, we discretize the fluid with 2D SPH particles and compute the height according to the density at each particle location. The particle discretization offers the benefits that it simplifies the use of sparsely filled domains and arbitrary boundary geometry. Our solver can handle terrain slopes and supports two-way coupling of the particle-based height field with rigid objects. An improved surface definition is presented that reduces visible bumps related to the underlying particle representation. It furthermore smoothes areas with separating particles to achieve better rendering results. Both the physics and the rendering are implemented on modern GPUs resulting in interactive performances in all our presented examples. Categories and Subject Descriptors (according to ACM CCS): I.3.5 [Computer Graphics]: Computational Geometry and Object Modeling—Physically Based Modeling; I.3.7 [Computer Graphics]: Three-Dimensional Graphics and Realism—Animation and Virtual Reality 1. Introduction in height field methods as well as in full 3D simulations. The grid discretization allows for efficient simulations, but Physically-based simulations have become an important el- handling irregular domain boundaries that are not aligned ement of real-time applications like computer games. -
Santa Rosa County Tsunami/Rogue Wave
SANTA ROSA COUNTY TSUNAMI/ROGUE WAVE EVACUATION PLAN Banda Aceh, Indonesia, December 2004, before/after tsunami photos 1 Table of Contents Introduction …………………………………………………………………………………….. 3 Purpose…………………………………………………………………………………………. 3 Definitions………………………………………………………………………………………… 3 Assumptions……………………………………………………………. ……………………….. 4 Participants……………………………………………………………………………………….. 4 Tsunami Characteristics………………………………………………………………………….. 4 Tsunami Warning Procedure…………………………………………………………………….. 6 National Weather Service Tsunami Warning Procedures…………………………………….. 7 Basic Plan………………………………………………………………………………………….. 10 Concept of Operations……………………………………………………………………………. 12 Public Awareness Campaign……………………………………………………………………. 10 Resuming Normal Operations…………………………………………………………………….13 Tsunami Evacuation Warning Notice…………………………………………………………….14 2 INTRODUCTION: Santa Rosa County Emergency Management developed a Santa Rosa County-specific Tsunami/Rogue wave Evacuation Plan. In the event a Tsunami1 threatens Santa Rosa County, the activation of this plan will guide the actions of the responsible agencies in the coordination and evacuation of Navarre Beach residents and visitors from the beach and other threatened areas. The goal of this plan is to provide for the timely evacuation of the Navarre Beach area in the event of a Tsunami Warning. An alternative to evacuating Navarre Beach residents off of the barrier island involves vertical evacuation. Vertical evacuation consists of the evacuation of persons from an entire area, floor, or wing of a building -
Deep Ocean Wind Waves Ch
Deep Ocean Wind Waves Ch. 1 Waves, Tides and Shallow-Water Processes: J. Wright, A. Colling, & D. Park: Butterworth-Heinemann, Oxford UK, 1999, 2nd Edition, 227 pp. AdOc 4060/5060 Spring 2013 Types of Waves Classifiers •Disturbing force •Restoring force •Type of wave •Wavelength •Period •Frequency Waves transmit energy, not mass, across ocean surfaces. Wave behavior depends on a wave’s size and water depth. Wind waves: energy is transferred from wind to water. Waves can change direction by refraction and diffraction, can interfere with one another, & reflect from solid objects. Orbital waves are a type of progressive wave: i.e. waves of moving energy traveling in one direction along a surface, where particles of water move in closed circles as the wave passes. Free waves move independently of the generating force: wind waves. In forced waves the disturbing force is applied continuously: tides Parts of an ocean wave •Crest •Trough •Wave height (H) •Wavelength (L) •Wave speed (c) •Still water level •Orbital motion •Frequency f = 1/T •Period T=L/c Water molecules in the crest of the wave •Depth of wave base = move in the same direction as the wave, ½L, from still water but molecules in the trough move in the •Wave steepness =H/L opposite direction. 1 • If wave steepness > /7, the wave breaks Group Velocity against Phase Velocity = Cg<<Cp Factors Affecting Wind Wave Development •Waves originate in a “sea”area •A fully developed sea is the maximum height of waves produced by conditions of wind speed, duration, and fetch •Swell are waves -
Soliton and Rogue Wave Statistics in Supercontinuum Generation In
Soliton and rogue wave statistics in supercontinuum generation in photonic crystal fibre with two zero dispersion wavelengths Bertrand Kibler, Christophe Finot, John M. Dudley To cite this version: Bertrand Kibler, Christophe Finot, John M. Dudley. Soliton and rogue wave statistics in supercon- tinuum generation in photonic crystal fibre with two zero dispersion wavelengths. The European Physical Journal. Special Topics, EDP Sciences, 2009, 173 (1), pp.289-295. 10.1140/epjst/e2009- 01081-y. hal-00408633 HAL Id: hal-00408633 https://hal.archives-ouvertes.fr/hal-00408633 Submitted on 17 Apr 2010 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. EPJ manuscript No. (will be inserted by the editor) Soliton and rogue wave statistics in supercontinuum generation in photonic crystal ¯bre with two zero dispersion wavelengths Bertrand Kibler,1 Christophe Finot1 and John M. Dudley2 1 Institut Carnot de Bourgogne, UMR 5029 CNRS-Universit¶ede Bourgogne, 9 Av. A. Savary, Dijon, France 2 Institut FEMTO-ST, UMR 6174 CNRS-Universit¶ede Franche-Comt¶e,Route de Gray, Besan»con, France. Abstract. Stochastic numerical simulations are used to study the statistical prop- erties of supercontinuum spectra generated in photonic crystal ¯bre with two zero dispersion wavelengths. -
MAR 110 LECTURE #22 Standing Waves and Tides
27 October 2007 MAR110_Lec22_standing Waves_tides_27oct07.doc 1 MAR 110 LECTURE #22 Standing Waves and Tides Coastal Zone – Beach Profile Figure 22.1 Beach Profile Summer Onshore Sand Transport Breaking Swell Currents Erode Bar Sand…. & Build the Summer Berm Figure 22.2 Beach Evolution – Summer Onshore Transport 27 October 2007 MAR110_Lec22_standing Waves_tides_27oct07.doc 2 Winter Offshore Sand Transport Winter Storm Wave Currents Erode Beach Sand…. to form sandbars Figure 22.3 Beach Evolution – Winter Offshore Transport No Net Motion or Energy Propagation Figure 22.4 Wave Reflection and Standing Waves A standing wave does not travel or propagate but merely oscillates up and down with stationary nodes (with no vertical movement) and antinodes (with the maximum possible movement) that oscillates between the crest and the trough. A standing wave occurs when the wave hits a barrier such as a seawall exactly at either the wave’s crest or trough, causing the reflected wave to be a mirror image of the original. (??) 27 October 2007 MAR110_Lec22_standing Waves_tides_27oct07.doc 3 Standing Waves and a Bathtub Seiche Figure 22.5 Standing Waves Standing waves can also occur in an enclosed basin such as a bathtub. In such a case, at the center of the basin there is no vertical movement and the location of this node does not change while at either end is the maximum vertical oscillation of the water. This type of waves is also known as a seiche and occurs in harbors and in large enclosed bodies of water such as the Great Lakes. (??, ??) Standing Wave or Seiche Period l Figure 22.6 Seiche Period The wavelength of a standing wave is equal to twice the length of the basin it is in, which along with the depth (d) of the water within the basin, determines the period (T) of the wave.