DOCSLIB.ORG

Coupling of Sea Level and Tidal Range Changes, with Implications for Future Water Levels

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text

Load more

Portland State University PDXScholar Civil and Environmental Engineering Faculty Publications and Presentations Civil and Environmental Engineering 2017 Coupling of Sea Level and Tidal Range Changes, with Implications for Future Water levels Adam T. Devlin Portland State University David A. Jay Portland State University Stefan Talke Portland State University, [email protected] Edward D. Zaron Portland State University, [email protected] Jiayi Pan The Chinese University of Hong Kong See next page for additional authors Follow this and additional works at: https://pdxscholar.library.pdx.edu/cengin_fac Part of the Environmental Engineering Commons Let us know how access to this document benefits ou.y Citation Details Devlin, Adam T.; Jay, David A.; Talke, Stefan; Zaron, Edward D.; Pan, Jiayi; and Lin, Hui, "Coupling of Sea Level and Tidal Range Changes, with Implications for Future Water levels" (2017). Civil and Environmental Engineering Faculty Publications and Presentations. 429. https://pdxscholar.library.pdx.edu/cengin_fac/429 This Article is brought to you for free and open access. It has been accepted for inclusion in Civil and Environmental Engineering Faculty Publications and Presentations by an authorized administrator of PDXScholar. Please contact us if we can make this document more accessible: [email protected]. Authors Adam T. Devlin, David A. Jay, Stefan Talke, Edward D. Zaron, Jiayi Pan, and Hui Lin This article is available at PDXScholar: https://pdxscholar.library.pdx.edu/cengin_fac/429 www.nature.com/scientificreports OPEN Coupling of sea level and tidal range changes, with implications for future water levels Received: 9 June 2017 Adam T. Devlin1,2, David A. Jay2, Stefan A. Talke2, Edward D. Zaron2, Jiayi Pan1,3,4 & Hui Lin1 Accepted: 10 November 2017 Are perturbations to ocean tides correlated with changing sea-level and climate, and how will this Published: xx xx xxxx afect high water levels? Here, we survey 152 tide gauges in the Pacifc Ocean and South China Sea and statistically evaluate how the sum of the four largest tidal constituents, a proxy for the highest astronomical tide (HAT), changes over seasonal and interannual time scales. We fnd that the variability in HAT is signifcantly correlated with sea-level variability; approximately 35% of stations exhibit a greater than ±50 mm tidal change per meter sea-level fuctuation. Focusing on a subset of three stations with long records, probability density function (PDF) analyses of the 95% percentile exceedance of total sea level (TSL) show long-term changes of this high-water metric. At Hong Kong, the increase in tides signifcantly amplifes the risk caused by sea-level rise. Regions of tidal decrease and/or amplifcation highlight the non-linear response to sea-level variations, with the potential to amplify or mitigate against the increased food risk caused by sea-level rise. Overall, our analysis suggests that in many regions, local food level determinations should consider the joint efects of non- stationary tides and mean sea level (MSL) at multiple time scales. Worldwide, ocean tides have exhibited trends over the past century that cannot be explained by the orbital mechanics underlying predictable tidal variability1,2. Regional studies have shown changes in major diurnal and semidiurnal tides in the Eastern Pacifc3, in the Gulf of Maine4, in the North Atlantic5,6, in China7,8, in Japan9, and at islands throughout the Pacifc10. Alongside these changes, mean sea level (MSL) has been increasing at a global rate of +1.7 ± 0.2 mm yr−1 as estimated from coastal and island tide gauge measurements from 1900–2009, and +3.4 ± 0.4 mm yr−1 for 1993–2016 as estimated from satellite altimetry11,12. A recent calculation shows the satel- lite era rate to be closer to +3.0 mmyr−1, though the last decade showed a faster rise, presumably from increased ice melt in Greenland13. However, this increase is not spatially uniform; Western Pacifc MSL rise rates exceed +10 mmyr−1 in some locations, whereas Eastern Pacifc rates are ofen zero or negative14,15. Climate models pre- dict that MSL rates will accelerate in upcoming decades through global climate change mechanisms16 such as ice sheet melt and thermosteric MSL rise due to upper-ocean warming17–24. Both MSL and tides exhibit short-term (seasonal to decadal) variability, in addition to long-term trends25. Tide properties can be altered by depth changes26 including those caused by MSL rise27, or by mechanisms driving MSL rise, such as increased surface water temperatures28. In either case, societal consequences are ofen due to total sea level, which is the sum of MSL and the time-variable water level (including tides). Terefore, both tides and MSL should be considered together in assessing the signifcance of future sea-level changes29. Figure 1 shows a simple cartoon of the various mechanisms that can afect MSL and tides. Changes in water depth (ΔH) can be due to changes in density (Δρ), which is a function of water temperature (Tw). An increase in 17 Tw will decrease the density of the upper layer (ρu), increasing ΔH . Altered frictional efects (Δr) can manifest from changes in ΔH27. Te “coupled oscillator” efect between the shelf regions and the open ocean can lead to modifcations of tidal amplitudes via changing Δr and frequency-dependent tidal responses to astronomical 29 forcing (ΔΨω) for multiple tides . Internal tides can change via modulations of ΔH and Δρ, which can change the wave phase relative to the barotropic tide, which can modulate the surface expression of the tidal amplitude30. Resonance is a function of ΔH and ΔΨω; small changes in ΔH may change the resonance of enclosed bays 1The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, SAR, China. 2Portland State University, Portland, OR, United States of America. 3College of Marine Science, Nanjing University of Information Science and Technology, Nanjing, 210044, China. 4Shenzhen Research Institute, The Chinese University of Hong Kong, Shenzhen, Guangdong, 518057, China. Correspondence and requests for materials should be addressed to A.T.D. (email: [email protected]) SCIENTIFIC REPORTS | 7: 17021 | DOI:10.1038/s41598-017-17056-z 1 www.nature.com/scientificreports/ Figure 1. Schematic cartoon showing some of the mechanisms that can afect MSL and tides. See text above for details. Relevant reference citation numbers are indicated in fgure by superscript. 31 and harbors through modifcation of ΔΨω that may either increase or decrease tidal amplitudes . Water depth changes are also dependent on ΔQr in estuarine locations. An increase in ΔQr will certainly increase MSL locally, but the increased friction of the incoming tide interacting with the outgoing river discharge will change Δr, decreasing tidal amplitude32. Finally, on a larger scale, changes in ΔH can also afect the structure of basin-wide amphidromic systems via movement of the co-tidal lines33. Another mechanism not shown on this fgure is that of resonant triad interactions, such as between the M2, K1, and O1 tides, which can be amplifed through changes in ΔH and Δρ that change local geometry and modulate all three tidal amplitudes in the relationship25. Te correlations of multiple forcing mechanisms make it challenging to determine the causes behind the linked variability of MSL and tides that is observed at many locations34,35. However, the presence of correlations between sea-level and tides indicates that one or more of these processes is at work. In summary, previous studies suggest that changes in the amplitude and phase of a tidal constituent may be a function of multiple variables: Δ=ΔΔ ΔΔρ ΔΔΨ ... Amp(tidal fH,,Qmrx,,r,,ω ) (1) where H is the water depth, ρ is water density, r is friction, mx is mixing, Qr is river discharge, and Ψω represents frequency-dependent tidal response to astronomical tidal forcing. Te “…” indicates other variables not listed here, such as wind. Since many of the variables which afect sea-level (river fow, density, wind) can also afect tidal amplitudes, a correlated response is frequently observed. Identifying connections and correlations between tidal range and MSL is critical for making reliable predic- tions of coastal water levels and inundation risk. When combined with storm surge, larger tides and higher MSL may amplify food risk, coastal inundation, damage to infrastructure, and population displacement. Even with- out the consideration of storm surge, changes in tides and sea-levels may lead to more occurrences of nuisance fooding, also known as “sunny day fooding”, which now occurs at high tide many locations, particularly along the US East and Gulf coasts36–38. Numerous factors contribute to nuisance fooding, including ocean swell and wave setup, local wind forcing, river fow, and the degradation of natural and man-made barriers. Hence, the joint efects of changes in tidal range and MSL are signifcant and of widespread relevance. Figure 2 shows four conceptually possible relationships of MSL rise and tidal change. Coupled changes of tides and MSL Tidal range changes are quantifed using tidal anomaly correlations (TACs), the ratio of short-term variability of tidal admittances to short-term MSL variability afer removing long-term trends25,34,35. Tis method deter- mines the sensitivity of tidal constituents to sea-level perturbations. Determinations of MSL and tidal variability are computed from harmonic analyses of hourly water level at 152 Pacifc Ocean tide gauge stations, using the absolute value of the complex amplitude sum of the four largest tidal components (the two largest semidiurnal constituents, M2 and S2, the two largest diurnal components, K1 and O1), and yearly MSL. Te M2, S2, K1, and O1 variabilities are summed (as complex amplitudes) to produce a combined tidal variability that is compared to MSL, and is used here as an approximation for the change in the highest astronomical tide per unit sea-level rise (δ-HAT).
Recommended publications
  • Time and Tides in the Gulf of Maine a Dockside Dialogue Between Two Old Friends

    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

    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 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.
  • Tidal Hydrodynamic Response to Sea Level Rise and Coastal Geomorphology in the Northern Gulf of Mexico

    Tidal Hydrodynamic Response to Sea Level Rise and Coastal Geomorphology in the Northern Gulf of Mexico

    University of Central Florida STARS Electronic Theses and Dissertations, 2004-2019 2015 Tidal hydrodynamic response to sea level rise and coastal geomorphology in the Northern Gulf of Mexico Davina Passeri University of Central Florida Part of the Civil Engineering Commons Find similar works at: https://stars.library.ucf.edu/etd University of Central Florida Libraries http://library.ucf.edu This Doctoral Dissertation (Open Access) is brought to you for free and open access by STARS. It has been accepted for inclusion in Electronic Theses and Dissertations, 2004-2019 by an authorized administrator of STARS. For more information, please contact [email protected]. STARS Citation Passeri, Davina, "Tidal hydrodynamic response to sea level rise and coastal geomorphology in the Northern Gulf of Mexico" (2015). Electronic Theses and Dissertations, 2004-2019. 1429. https://stars.library.ucf.edu/etd/1429 TIDAL HYDRODYNAMIC RESPONSE TO SEA LEVEL RISE AND COASTAL GEOMORPHOLOGY IN THE NORTHERN GULF OF MEXICO by DAVINA LISA PASSERI B.S. University of Notre Dame, 2010 A thesis submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Civil, Environmental, and Construction Engineering in the College of Engineering and Computer Science at the University of Central Florida Orlando, Florida Spring Term 2015 Major Professor: Scott C. Hagen © 2015 Davina Lisa Passeri ii ABSTRACT Sea level rise (SLR) has the potential to affect coastal environments in a multitude of ways, including submergence, increased flooding, and increased shoreline erosion. Low-lying coastal environments such as the Northern Gulf of Mexico (NGOM) are particularly vulnerable to the effects of SLR, which may have serious consequences for coastal communities as well as ecologically and economically significant estuaries.
  • Slow Persistent Mixing in the Abyss

    Slow Persistent Mixing in the Abyss

    Reference: van Haren, H., 2020. Slow persistent mixing in the abyss. Ocean Dyn., 70, 339- 352. Slow persistent mixing in the abyss by Hans van Haren* Royal Netherlands Institute for Sea Research (NIOZ) and Utrecht University, P.O. Box 59, 1790 AB Den Burg, the Netherlands. *e-mail: [email protected] Abstract Knowledge about deep-ocean turbulent mixing and flow circulation above abyssal hilly plains is important to quantify processes for the modelling of resuspension and dispersal of sediments in areas where turbulence sources are expected to be relatively weak. Turbulence may disperse sediments from artificial deep-sea mining activities over large distances. To quantify turbulent mixing above the deep-ocean floor around 4000 m depth, high-resolution moored temperature sensor observations have been obtained from the near-equatorial southeast Pacific (7°S, 88°W). Models demonstrate low activity of equatorial flow dynamics, internal tides and surface near-inertial motions in the area. The present observations demonstrate a Conservative Temperature difference of about 0.012°C between 7 and 406 meter above the bottom (hereafter, mab, for short), which is a quarter of the adiabatic lapse rate. The very weakly stratified waters with buoyancy periods between about six hours and one day allow for slowly varying mixing. The calculated turbulence dissipation rate values are half to one order of magnitude larger than those from open-ocean turbulent exchange well away from bottom topography and surface boundaries. In the deep, turbulent overturns extend up to 100 m tall, in the ocean-interior, and also reach the lowest sensor. The overturns are governed by internal-wave-shear and -convection.
  • Tidal Resonance in the Gulf of Thailand

    Tidal Resonance in the Gulf of Thailand

    Ocean Sci., 15, 321–331, 2019 https://doi.org/10.5194/os-15-321-2019 © Author(s) 2019. This work is distributed under the Creative Commons Attribution 4.0 License. Tidal resonance in the Gulf of Thailand Xinmei Cui1,2, Guohong Fang1,2, and Di Wu1,2 1First Institute of Oceanography, Ministry of Natural Resources, Qingdao, 266061, China 2Laboratory for Regional Oceanography and Numerical Modelling, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237, China Correspondence: Guohong Fang (fanggh@fio.org.cn) Received: 12 August 2018 – Discussion started: 24 August 2018 Revised: 1 February 2019 – Accepted: 18 February 2019 – Published: 29 March 2019 Abstract. The Gulf of Thailand is dominated by diurnal 1323 m. If the GOT is excluded, the mean depth of the rest tides, which might be taken to indicate that the resonant fre- of the SCS (herein called the SCS body and abbreviated as quency of the gulf is close to one cycle per day. However, SCSB) is 1457 m. Tidal waves propagate into the SCS from when applied to the gulf, the classic quarter-wavelength res- the Pacific Ocean through the Luzon Strait (LS) and mainly onance theory fails to yield a diurnal resonant frequency. In propagate in the southwest direction towards the Karimata this study, we first perform a series of numerical experiments Strait, with two branches that propagate northwestward and showing that the gulf has a strong response near one cycle per enter the Gulf of Tonkin and the GOT. The energy fluxes day and that the resonance of the South China Sea main area through the Mindoro and Balabac straits are negligible (Fang has a critical impact on the resonance of the gulf.
  • How a Tide Clock Works.Pub

    How a Tide Clock Works.Pub

    Conventional time clocks have a 12 hour cycle, with 1 hand for hours, another for minutes. Tide clocks have a single hand, and a cycle of 12 hours 25 minutes, coinciding to an average time of about 6 hours 12 minutes between high and low tides. High tide is indicated when the hand is at the ‘12 o’clock’ position, low tide is indicated with the hand at the ‘6 o’clock’ position. A tide clock is not indicating 6 or 12 o’clock of course. It is merely a convenient reference point on the dial, showing us when our local tide is high or low. 12 is marked as High, 6 is marked as Low. However, the hour markings on the dial between the High and Low tide points do show us the number of hours since the last high or low tide, and the hours before the next high or low tide. A tide clock which has been initially set correctly will continue to display tide predictions quite accurately, requiring resetting only at intervals of about 4 months, depending upon the location. A brief explanation of how the tidal cycle works The Moon is the major cause of the tides. The ‘lunar day’ (the time it takes for the Moon to re-appear at the same place in the sky) is 24 hours and 50 minutes. New Zealand, and many other places in the world, have 2 high tides and 2 low tides each day. These are called semi-diurnal tides. Some areas of the world (eg Freemantle in Australia), have only one tide cycle per day, known as diurnal tides.

  • Ocean Acoustic Tomography Has Heat Content, Velocity, and Vorticity in the North Pacific Thermohaline Circulation and Climate

    B. Dushaw, G. Bold, C.-S. Chiu, J. Colosi, B. Cornuelle, Y. Desaubies, M. Dzieciuch, A. Forbes, F. Gaillard, Brian Dushaw, Bruce Howe A. Gavrilov, J. Gould, B. Howe, M. Lawrence, J. Lynch, D. Menemenlis, J. Mercer, P. Mikhalevsky, W. Munk, Applied Physics Laboratory and School of Oceanography I. Nakano, F. Schott, U. Send, R. Spindel, T. Terre, P. Worcester, C. Wunsch, Observing the Ocean in the 2000’s: College of Ocean and Fisheries Sciences A Strategy for the Role of Acoustic Tomography in Ocean Climate Observation. In: Observing the Ocean Ocean Acoustic Tomography: 1970–21st Century University of Washington Ocean Acoustic Tomography: 1970–21st Century http://staff.washington.edu/dushaw in the 21st Century, C.J. Koblinsky and N.R. Smith (eds), Bureau of Meteorology, Melbourne, Australia, 2001. ABSTRACT PROCESS EXPERIMENTS Deep Convection—Greenland and Labrador Seas ATOC—Acoustic Thermometry of Ocean Climate Oceanic convection connects the surface ocean to the deep ocean with important consequences for the global Since it was first proposed in the late 1970’s (Munk and Wunsch 1979, 1982), ocean acoustic tomography has Heat Content, Velocity, and Vorticity in the North Pacific thermohaline circulation and climate. Deep convection occurs in only a few locations in the world, and is difficult The goal of the ATOC project is to measure the ocean temperature on basin scales and to understand the evolved into a remote sensing technique employed in a wide variety of physical settings. In the context of to observe. Acoustic arrays provide both the spatial coverage and temporal resolution necessary to observe variability. The acoustic measurements inherently average out mesoscale and internal wave noise that long-term oceanic climate change, acoustic tomography provides integrals through the mesoscale and other The 1987 reciprocal acoustic tomography experiment (RTE87) obtained unique measurements of gyre-scale deep-water formation.
  • Internal Tides in the Solomon Sea in Contrasted ENSO Conditions

    Internal Tides in the Solomon Sea in Contrasted ENSO Conditions

    Ocean Sci., 16, 615–635, 2020 https://doi.org/10.5194/os-16-615-2020 © Author(s) 2020. This work is distributed under the Creative Commons Attribution 4.0 License. Internal tides in the Solomon Sea in contrasted ENSO conditions Michel Tchilibou1, Lionel Gourdeau1, Florent Lyard1, Rosemary Morrow1, Ariane Koch Larrouy1, Damien Allain1, and Bughsin Djath2 1Laboratoire d’Etude en Géophysique et Océanographie Spatiales (LEGOS), Université de Toulouse, CNES, CNRS, IRD, UPS, Toulouse, France 2Helmholtz-Zentrum Geesthacht, Max-Planck-Straße 1, Geesthacht, Germany Correspondence: Michel Tchilibou ([email protected]), Lionel Gourdeau ([email protected]), Florent Lyard (fl[email protected]), Rosemary Morrow ([email protected]), Ariane Koch Larrouy ([email protected]), Damien Allain ([email protected]), and Bughsin Djath ([email protected]) Received: 1 August 2019 – Discussion started: 26 September 2019 Revised: 31 March 2020 – Accepted: 2 April 2020 – Published: 15 May 2020 Abstract. Intense equatorward western boundary currents the tidal effects over a longer time. However, when averaged transit the Solomon Sea, where active mesoscale structures over the Solomon Sea, the tidal effect on water mass transfor- exist with energetic internal tides. In this marginal sea, the mation is an order of magnitude less than that observed at the mixing induced by these features can play a role in the ob- entrance and exits of the Solomon Sea. These localized sites served water mass transformation. The objective of this paper appear crucial for diapycnal mixing, since most of the baro- is to document the M2 internal tides in the Solomon Sea and clinic tidal energy is generated and dissipated locally here, their impacts on the circulation and water masses, based on and the different currents entering/exiting the Solomon Sea two regional simulations with and without tides.
  • II. Causes of Tides III. Tidal Variations IV. Lunar Day and Frequency of Tides V

    II. Causes of Tides III. Tidal Variations IV. Lunar Day and Frequency of Tides V

    Tides I. What are Tides? II. Causes of Tides III. Tidal Variations IV. Lunar Day and Frequency of Tides V. Monitoring Tides Wikimedia FoxyOrange [CC BY-SA 3.0 Tides are not explicitly included in the NGSS PerFormance Expectations. From the NGSS Framework (M.S. Space Science): “There is a strong emphasis on a systems approach, using models oF the solar system to explain astronomical and other observations oF the cyclic patterns oF eclipses, tides, and seasons.” From the NGSS Crosscutting Concepts: Observed patterns in nature guide organization and classiFication and prompt questions about relationships and causes underlying them. For Elementary School: • Similarities and diFFerences in patterns can be used to sort, classiFy, communicate and analyze simple rates oF change For natural phenomena and designed products. • Patterns oF change can be used to make predictions • Patterns can be used as evidence to support an explanation. For Middle School: • Graphs, charts, and images can be used to identiFy patterns in data. • Patterns can be used to identiFy cause-and-eFFect relationships. The topic oF tides have an important connection to global change since spring tides and king tides are causing coastal Flooding as sea level has been rising. I. What are Tides? Tides are one oF the most reliable phenomena on Earth - they occur on a regular and predictable cycle. Along with death and taxes, tides are a certainty oF liFe. Tides are apparent changes in local sea level that are the result of long-period waves that move through the oceans. Photos oF low and high tide on the coast oF the Bay oF Fundy in Canada.
  • Resonant Interactions of Surface and Internal Waves with Seabed Topography by Louis-Alexandre Couston a Dissertation Submitted I

    Resonant Interactions of Surface and Internal Waves with Seabed Topography by Louis-Alexandre Couston a Dissertation Submitted I

    Resonant Interactions of Surface and Internal Waves with Seabed Topography By Louis-Alexandre Couston A dissertation submitted in partial satisfaction of the requirements for the degree of Doctorate of Philosophy in Engineering - Mechanical Engineering in the Graduate Division of the University of California, Berkeley Committee in Charge: Professor Mohammad-Reza Alam, Chair Professor Ronald W. Yeung Professor Philip S. Marcus Professor Per-Olof Persson Spring 2016 Abstract Resonant Interactions of Surface and Internal Waves with Seabed Topography by Louis-Alexandre Couston Doctor of Philosophy in Engineering - Mechanical Engineering University of California, Berkeley Professor Mohammad-Reza Alam, Chair This dissertation provides a fundamental understanding of water-wave transformations over seabed corrugations in the homogeneous as well as in the stratified ocean. Contrary to a flat or mildly sloped seabed, over which water waves can travel long distances undisturbed, a seabed with small periodic variations can strongly affect the propagation of water waves due to resonant wave-seabed interactions{a phenomenon with many potential applications. Here, we investigate theoretically and with direct simulations several new types of wave transformations within the context of inviscid fluid theory, which are different than the classical wave Bragg reflection. Specifically, we show that surface waves traveling over seabed corrugations can become trapped and amplified, or deflected at a large angle (∼ 90◦) relative to the incident direction of propagation. Wave trapping is obtained between two sets of parallel corrugations, and we demonstrate that the amplification mechanism is akin to the Fabry-Perot resonance of light waves in optics. Wave deflection requires three-dimensional and bi-chromatic corrugations and is obtained when the surface and corrugation wavenumber vectors satisfy a newly found class I2 Bragg resonance condition.
  • Estuarine Tidal Response to Sea Level Rise: the Significance of Entrance Restriction

    Estuarine Tidal Response to Sea Level Rise: the Significance of Entrance Restriction

    Estuarine, Coastal and Shelf Science 244 (2020) 106941 Contents lists available at ScienceDirect Estuarine, Coastal and Shelf Science journal homepage: http://www.elsevier.com/locate/ecss Estuarine tidal response to sea level rise: The significance of entrance restriction Danial Khojasteh a,*, Steve Hottinger a,b, Stefan Felder a, Giovanni De Cesare b, Valentin Heimhuber a, David J. Hanslow c, William Glamore a a Water Research Laboratory, School of Civil and Environmental Engineering, UNSW, Sydney, NSW, Australia b Platform of Hydraulic Constructions (PL-LCH), Ecole Polytechnique F´ed´erale de Lausanne (EPFL), Lausanne, Switzerland c Science, Economics and Insights Division, Department of Planning, Industry and Environment, NSW Government, Locked Bag 1002 Dangar, NSW 2309, Australia ARTICLE INFO ABSTRACT Keywords: Estuarine environments, as dynamic low-lying transition zones between rivers and the open sea, are vulnerable Estuarine hydrodynamics to sea level rise (SLR). To evaluate the potential impacts of SLR on estuarine responses, it is necessary to examine Tidal asymmetry the altered tidal dynamics, including changes in tidal amplification, dampening, reflection (resonance), and Resonance deformation. Moving beyond commonly used static approaches, this study uses a large ensemble of idealised Idealised method estuarine hydrodynamic models to analyse changes in tidal range, tidal prism, phase lag, tidal current velocity, Ensemble modelling Cluster analysis and tidal asymmetry of restricted estuaries of varying size, entrance configuration and tidal forcing as well as three SLR scenarios. For the first time in estuarine SLR studies, data analysis and clustering approaches were employed to determine the key variables governing estuarine hydrodynamics under SLR. The results indicate that the hydrodynamics of restricted estuaries examined in this study are primarily governed by tidal forcing at the entrance and the estuarine length.