DOCSLIB.ORG

Nearshore!Currents!In!South/ Eastern!Scania!

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text

Load more

Master!Thesis!! TVVR!16/5015 ! Nearshore!Currents!in!South/ eastern!Scania! ________________________________________________ Emanuel!Schmidt! ! ! ! Division!of!Water!Resources!Engineering! Department!of!Building!and!Environmental!Technology! Lund!University! Nearshore Currents in Southeastern Scania Master Thesis Supervisors: Author: Magnus Larson Emanuel Schmidt Caroline Fredriksson Division of Water Resources Engineering Lund University Box 118 221 00 Lund, Sweden ii Water Resources Engineering TVVR-16/5015 ISSN 1101-9824 Lund 2016 www.tvrl.lth.se iii Master Thesis Division of Water Resources Engineering Lund University English Title: Nearshore Currents in Southeastern Scania Author: Emanuel Schmidt Supervisors: Magnus Larson, Caroline Fredriksson Examiner: Hans Hanson Language: English Year: 2016 Keywords: Nearshore currents; drifters; rip currents; beach morphology; swimming safety iv Acknowledgements First of all I would like to thank my supervisors Magnus Larson and Caroline Fredriksson for great enthusiasm regarding my project. You have been very kind, helpful and inspiring throughout my work with this thesis. I have had many good days of field work combined with surfing. I would also like to thank Max Radermacher from TU Delft for valuable input, useful tools and field work assistance in cold Baltic water. Further, I would like to thank the institution of TVRL for housing me, inviting me to floor ball and for many cups of co↵ee. It has been a great time working with the institution and I hope to see all of you again. Last but not least, I would like to thank my girlfriend N´ına for enduring all my endless hours of explaining rip currents and numerical models instead of discussing baby names. v Abstract The South East Coast of Scania is a popular destination for both Swedish and foreign tourists. The long and wide sandy beaches are well visited by swimmers and beachgoers, but the waters have shown to be treacherous at times. In Au- gust 2015, two German tourists drowned after getting caught in a probable rip current in the proximity of Hav¨ang beach. Six months after the accident, this thesis study, which aims to investigate the nearshore currents in the region was initiated. The main objective was to map the currents prevalent in the area, with special attention to the o↵shore directed rip currents. In order to accomplish this, GPS-equipped drifters were developed for in-field measurements. The field work includes both drifter measurements and grain size sampling. Data of the local bathymetry from the project Sk˚anestrand was studied and a bathy- metric survey was conducted. The study also includes o↵shore wave hindcasting and modeling of the wave transformation as waves approach shore. Drifter measurements were conducted on four beaches at varying wave condi- tions. On 17-18 September 2016, rip currents were observed at Vitem¨olla beach. The o↵shore velocity of the current was found to be 0.4-1 m/s, which resembles velocities found in earlier studies (Winter et al. (2011), Dalrymple et al. (2011), Short (1985)). The other field measurements did not register any significant rip currents but rather strong longshore currents. The results from the wave trans- formation EBED model (with hindcasted waves as input) showed that a wave height variation along Vitem¨olla beach of more than 0.5 m can occur under the similar wave conditions. It was concluded that this could generate enough wave setup variation to drive rip currents. Furthermore, it can be concluded that most of the beaches within the study area are very dynamic, and in order to predict the nearshore currents with models up-to-date bathymetry and more reliable wave data is needed. With field measurements, literature studies and documentation of historical ac- cidents as a basis, a current map for the study area was developed. This study showed that the public should be attentive when swimming in the ocean when the beaches are subject to waves. A simple measure for preventing further accidents would be to red-flag all beaches under such conditions. vi Contents 1 Introduction 1 1.1 Background . 1 1.2 ResearchQuestionsandObjectives . 1 1.3 Methodology . 2 1.3.1 Literature Study . 2 1.3.2 Mapping of Rip Current Conditions . 2 1.3.3 Construction of Drifters . 2 1.3.4 FieldMeasurements . 3 1.3.5 Data Analysis . 3 1.4 ThesisStructure ............................ 3 2 Theoretical Background 4 2.1 Ocean Waves and Nearshore Transformation . 4 2.1.1 Wave Generation . 4 2.1.2 Refraction, Shoaling and Di↵raction . 5 2.2 WaveSetup............................... 6 2.3 Flux of Momentum Under Oblique Waves . 8 2.4 InfragravityWaves ........................... 8 2.5 Nearshore Currents . 9 2.5.1 Longshore Currents . 9 2.5.2 Undertow ............................ 10 2.5.3 RipCurrents .......................... 10 2.5.4 Backwash . 13 2.6 Beach Morphology and Storm Response . 13 2.6.1 The Beach State Classification . 14 2.7 SwimmerSafety............................. 17 3 Description of Study Area 19 3.1 StudySite................................ 19 3.2 Bathymetry............................... 21 3.3 WindandWaveClimate........................ 24 3.3.1 WindClimate.......................... 24 3.3.2 WaveClimate.......................... 25 3.4 History of Accidents . 28 3.5 InterviewswithLocalFishermen . 28 4 Drifter Development 30 4.1 DrifterDesign.............................. 30 4.2 DrifterConstruction .......................... 31 4.3 DrifterVelocityCalculations . 31 vii 5 Field Measurements 33 5.1 Complementary Bathymetry Measurements . 33 5.2 GrainSizeSampling .......................... 33 5.3 DrifterMeasurements ......................... 34 6 Field Measurement Results 35 6.1 GrainSizeSampling .......................... 35 6.2 Complementary Bathymetry Measurements . 36 6.3 Summary of Beach Properties . 38 6.4 CurrentTrackingwithGPS-Drifters . 38 6.4.1 Sandhammaren April 7 . 38 6.4.2 Vitem¨olla April 26 . 40 6.4.3 Kn¨ab¨ackshusen May 31 . 42 6.4.4 Vitem¨olla September 17-18 . 44 7 Numerical Modelling of Nearshore Wave Transformation 48 7.1 EBEDSimulation............................ 48 7.2 EBEDSimulationResults . 50 7.2.1 Vitem¨olla - 17 September 2016 - 19:00 . 51 7.2.2 Hav¨ang - 17 August 2015 - 13:00 . 53 7.3 Longshore Current Modelling . 55 8 Discussion 57 8.1 DrifterExperiments .......................... 57 8.2 Morphodynamics ............................ 58 8.3 Numerical Modelling of Nearshore Wave Transformation . 59 8.4 Safety Recommendations . 60 8.4.1 WarningSystem ........................ 62 8.5 FurtherResearch ............................ 63 9 Conclusions 64 10 Bibliography 65 11 Appendix 68 11.1 Wind Comparision . 68 11.2SPM-MF ................................ 69 11.3EBED.................................. 70 viii 1 Introduction 1.1 Background In August 2015 a tragic drowning accident occurred at Hav¨ang beach in eastern Scania, where two German tourists were pulled o↵shore, caught by a probable rip current (Helsingborgs Dagblad, 2015). The existence of strong o↵shore directed currents on the southeast coast of Scania is widely known among local residents and warning signs have been placed on the beaches to notify swimmers about the strong currents. However, the processes generating the currents are poorly understood and has not previously been studied in the area. This master thesis focus on studying the nearshore currents along the southeast coast of Scania and their basic characteristics. Understanding the nearshore hydro- and morphodynamic processes can help to predict where and when currents are formed. Identifying the conditions under which currents may occur is valuable to educate the public and may form the basis for a warning system to prevent further accidents. 1.2 Research Questions and Objectives The main objectives of this study is (1) to map the nearshore currents along the southeast coast of Scania, (2) to determine the underlying mechanisms and (3) to quantify their basic characteristics. This thesis aims to answer the following research questions: • What types of currents occur along the coastline? • Along which parts of the coastline in the study area do rip currents occur? • Under which wave conditions do rip currents occur? • How is beach morphology coupled to currents? • How can knowledge about nearshore currents be used in coastal- and safety management in southeast Scania? Based on an initial investigation, some beaches will be chosen as field study sites for which the following research questions will be investigated: • What is the rip cell morphology? • How strong is the rip current? 1 1.3 Methodology The study is divided into five main parts: 1) a literature study, 2) mapping of nearshore current conditions, 3) construction of drifters 4) field measurements, and 5) data analysis. 1.3.1 Literature Study International literature on nearshore currents is abundant, but most studies have been carried out at swell dominated coastlines. However, a few studies have been carried out at coastlines dominated by wind waves (e.g., Winter, 2011). The fo- cus of the literature study was to gain understanding of the physical processes of nearshore currents (especially rip currents) and other o↵shore directed currents, how they interact with beach morphology, and under which wave and morpholog- ical conditions they are likely to occur. The literature review also encompassed previous studies where field work has been performed as a preparation for the measurements to be carried out in the present study. 1.3.2 Mapping of Rip Current Conditions Based on the conceptual understanding
Recommended publications
  • Strategic Environmental Assessment of the Marine Spatial Plan Proposal for the Baltic Sea

    Strategic Environmental Assessment of the Marine Spatial Plan Proposal for the Baltic Sea

    Strategic Environmental Assessment of the Marine Spatial Plan proposal for the Baltic Sea Consultation document Swedish Agency for Marine and Water Management 2018 Swedish Agency for Marine and Water Management Date: 10/04/2018 Publisher: Björn Sjöberg Contact person environmental assessment and SEA: Jan Schmidtbauer Crona Swedish Agency for Marine and Water Management Box 11 930, SE-404 39 Gothenburg, Sweden www.havochvatten.se Photos, illustrations, etc.: Source Swedish Agency for Marine and Water Management unless otherwise stated. This strategic environmental assessment (SEA) was prepared by the consulting firm COWI AB on behalf of the Swedish Agency for Marine and Water Management (SwAM). Consultant: Mats Ivarsson, Assignment Manager, COWI Kristina Bernstén, Assignment Manager, SEA Selma Pacariz, Administrator, Environment Ulrika Roupé, Administrator, Environment Emelie von Bahr, Administrator, Environment Marian Ramos Garcia, Administrator, GIS Morten Hjorth and others Strategic Environmental Assessment Marine Spatial Plan – Baltic Sea Swedish Agency for Marine and Water Management 2017 Preface In the Marine Spatial Planning Ordinance, the Swedish Agency for Marine and Water Management (SwAM) is given the responsibility for preparing proposals on three marine spatial plans (MSPs) with associated strategic environmental assessments (SEA) in broad collaboration. The MSPs shall provide guidance to public authorities and municipalities in the planning and review of claims for the use of the marine spatial planning area. The plans shall contribute to sustainable development and shall be consistent with the objective of a good environmental status in the sea. In the work on marine spatial planning, SwAM prepared a current status report (SwAM report 2015:2) and a roadmap (SwAM 2016-21), which included the scope of the SEA.
  • A Case Study of the Gothenburg Pelagic Offshore Fishery

    A Case Study of the Gothenburg Pelagic Offshore Fishery

    Social-Ecological Resilience for Sustainable Development, 2012-2013 MSc. Thesis (article format), 60 ETC Stockholm Resilience Centre Stockholm University Is Growing Larger the Same as Becoming Resilient? A case study of the Gothenburg Pelagic Offshore Fishery Author: Maja Berggren Supervisors: Wijnand Boonstra, Henrik Österblom, Jonas Hentati-Sundberg Abstract Scale enlargement and increased use of market mechanisms to improve fisheries’ management are a trend in many fisheries. These developments have economic benefits, but can also lead to loss of social-ecological knowledge, resilience, and employment opportunities in fishing communities. Successful large-scale fishers who have access to quotas benefit from these trends, but they also risk ending up in a lock-in, where a high degree of specialisation of fishing activities makes them vulnerable to economic and ecological fluctuation. Economic theory explains scale enlargement as an effect of economies of scale, but it cannot explain why these effects occur for certain groups of fishers and not for others. This study addresses this knowledge gap by exploring a small group of pelagic offshore fishers in Gothenburg, Sweden, who stand out in terms of their scale enlargement, profitability and political influence. Recently they also contributed to a change of management system towards increased use of economic management tools (Individual Transferable Quotas, ITQs). Using interviews with actors within and outside the pelagic offshore fishery, combined with participant observations, I describe a number of factors that can explain the Swedish development towards scale enlargement. Important for this development, it seems, is the fishers’ ‘entrepreneurial spirit’ and flexibility towards changing conditions. These are qualities that, in turn, have been supported by different contextual factors including abundant pelagic stocks, regulatory changes and a supportive community culture.
  • Lesson 8: Currents

    Lesson 8: Currents

    Standards Addressed National Science Lesson 8: Currents Education Standards, Grades 9-12 Unifying concepts and Overview processes Physical science Lesson 8 presents the mechanisms that drive surface and deep ocean currents. The process of global ocean Ocean Literacy circulation is presented, emphasizing the importance of Principles this process for climate regulation. In the activity, students The Earth has one big play a game focused on the primary surface current names ocean with many and locations. features Lesson Objectives DCPS, High School Earth Science Students will: ES.4.8. Explain special 1. Define currents and thermohaline circulation properties of water (e.g., high specific and latent heats) and the influence of large bodies 2. Explain what factors drive deep ocean and surface of water and the water cycle currents on heat transport and therefore weather and 3. Identify the primary ocean currents climate ES.1.4. Recognize the use and limitations of models and Lesson Contents theories as scientific representations of reality ES.6.8 Explain the dynamics 1. Teaching Lesson 8 of oceanic currents, including a. Introduction upwelling, density, and deep b. Lecture Notes water currents, the local c. Additional Resources Labrador Current and the Gulf Stream, and their relationship to global 2. Extra Activity Questions circulation within the marine environment and climate 3. Student Handout 4. Mock Bowl Quiz 1 | P a g e Teaching Lesson 8 Lesson 8 Lesson Outline1 I. Introduction Ask students to describe how they think ocean currents work. They might define ocean currents or discuss the drivers of currents (wind and density gradients). Then, ask them to list all the reasons they can think of that currents might be important to humans and organisms that live in the ocean.
  • Earth Science Ocean Currents May 12, 2020

    Earth Science Ocean Currents May 12, 2020

    High School Science Virtual Learning Earth Science Ocean Currents May 12, 2020 High School Earth Science Lesson: May 12, 2020 Objective/Learning Target: Students will understand major ocean currents and how they impact Earth. Let’s Get Started: 1. What is the difference between weather and climate? 2. What is an ocean? Let’s Get Started: Answer Key 1. Weather is local & short term, climate is regional and long term 2. The ocean is a huge body of saltwater that covers about 71 percent of the Earth's surface Lesson Activity: Directions: 1. Read through the Following slides. 2. Answer the questions on your own paper. MAJOR OCEAN CURRENTS Terms 1. Coriolis Effect movement of wind and water to the right or left that is caused by Earth’s rotation 2. upwelling vertical movement of water toward the ocean’s surface 3. surface current is an ocean current that moves water horizontally and does not reach a depth of more than 400m. 4. gyre is when major surface currents form a circular system. MAJOR OCEAN CURRENTS A current is a large volume of water flowing in a certain direction. CAUSES OF OCEAN CURRENTS 1. One cause of an ocean current is friction between wind and the ocean surface. ○ Earth’s prevailing winds influence the formation and direction of surface currents. ○ Ex: tides, waves 2. In addition to the wind, the direction surface currents flow depends on the Coriolis effect. ○ The Coriolis effect results from Earth’s rotation. It influences the direction of flow of Earth’s water and air. 3.
  • Ocean Vocabulary

    Ocean Vocabulary

    Mrs. Hansgen's 7th Grade Science Name Date Ocean Vocabulary wave period breaker El Nino neap tides Coriolis effect swelling whitecap tidal range trough high tide tsunami deep current crest spring tides low tide surf surface current storm surge wavelength upwelling Matching Match each definition with a word. 1. Lowest point of a wave 2. a white, foaming wave with a very steep crest that breaks in the open ocean before the wave gets close to the shore 3. A curving of a moving object from a straight path due to the Earth's rotation. 4. An ocean current formed when steady winds blow over the surface of the ocean. 5. rolling waves that move in a steady procession across the ocean 6. when the ocean tide reaches the highest point on the shoreline 7. An abnormal climate event that occurs every 2 to 7 years in the Pacific Ocean, causing changes in winds, currents, and weather patterns, that can lead to dramatic changes. 8. a wave that forms when a large volume of ocean water is suddenly moved up or down 9. The distance between two adjacent wave crests or wave troughs 10. tides with minimum daily tidal range that occur during the first and third quarters of the moon 11. Highest point of a wave 12. a process in which cold, nutrient-rich water from the deep ocean rises to the surface and replaces warm surface water 13. ocean tide at its lowest point on the shore 14. the area between the breaker zone and the shore 15.
  • Ystad Sweden Jazz Festival 2018!

    Ystad Sweden Jazz Festival 2018!

    VÄLKOMMEN TILL/WELCOME TO YSTAD SWEDEN JAZZ FESTIVAL 2018! Kära jazzvänner! Dear friends, Vi känner stor glädje över att för nionde gången kunna presentera It is with great pleasure that we present, for the ninth time, en jazzfestival med många spännande och intressanta konserter. a jazz festival with many exciting and interesting concerts – a mix Megastjärnor och legendarer samsas med unga blivande stjärnor. of megastars, legends and young stars of tomorrow. As in 2017, we Liksom 2017 använder vi Ystad Arena för konserter vilket möjliggör will use Ystad Arena as a venue to enable more people to experience för fler att uppleva musiken. I år erbjuder vi 44 konserter med drygt the concerts. This year we will present over 40 concerts featuring 200 artister och musiker. Tillsammans med Ystads kommun fortsätter more than 200 artists and musicians. In cooperation with Ystad vi den viktiga satsningen på jazz för barn, JazzKidz. Barnkonserterna Municipality, we are continuing the important music initiative for ges på Ystads stadsbibliotek. Tre konserter ges på Solhällan i Löderup. children, JazzKidz. The concerts for children will be held at Ystad Bered er på en magisk upplevelse den 5 augusti, då vi erbjuder en unik Library. There will be three concerts at Solhällan in Löderup. And, konsert vid Ales stenar, på Kåseberga, i soluppgången. get ready for a magical experience on 5 August, when we will Jazzfestivalen arrangeras sedan 2011 av den ideella föreningen present a unique sunrise concert at Ales stenar, near Kåseberga. Ystad Sweden Jazz och Musik i Syd i ett viktigt och förtroendefullt The jazz festival has been arranged since 2011 by the non-profit samarbete.
  • OCEANS ´09 IEEE Bremen

    OCEANS ´09 IEEE Bremen

    11-14 May Bremen Germany Final Program OCEANS ´09 IEEE Bremen Balancing technology with future needs May 11th – 14th 2009 in Bremen, Germany Contents Welcome from the General Chair 2 Welcome 3 Useful Adresses & Phone Numbers 4 Conference Information 6 Social Events 9 Tourism Information 10 Plenary Session 12 Tutorials 15 Technical Program 24 Student Poster Program 54 Exhibitor Booth List 57 Exhibitor Profiles 63 Exhibit Floor Plan 94 Congress Center Bremen 96 OCEANS ´09 IEEE Bremen 1 Welcome from the General Chair WELCOME FROM THE GENERAL CHAIR In the Earth system the ocean plays an important role through its intensive interactions with the atmosphere, cryo- sphere, lithosphere, and biosphere. Energy and material are continually exchanged at the interfaces between water and air, ice, rocks, and sediments. In addition to the physical and chemical processes, biological processes play a significant role. Vast areas of the ocean remain unexplored. Investigation of the surface ocean is carried out by satellites. All other observations and measurements have to be carried out in-situ using research vessels and spe- cial instruments. Ocean observation requires the use of special technologies such as remotely operated vehicles (ROVs), autonomous underwater vehicles (AUVs), towed camera systems etc. Seismic methods provide the foundation for mapping the bottom topography and sedimentary structures. We cordially welcome you to the international OCEANS ’09 conference and exhibition, to the world’s leading conference and exhibition in ocean science, engineering, technology and management. OCEANS conferences have become one of the largest professional meetings and expositions devoted to ocean sciences, technology, policy, engineering and education.
  • Ocean Wind and Current Retrievals Based on Satellite SAR Measurements in Conjunction with Buoy and HF Radar Data

    Ocean Wind and Current Retrievals Based on Satellite SAR Measurements in Conjunction with Buoy and HF Radar Data

    remote sensing Article Ocean Wind and Current Retrievals Based on Satellite SAR Measurements in Conjunction with Buoy and HF Radar Data He Fang 1, Tao Xie 1,* ID , William Perrie 2, Li Zhao 1, Jingsong Yang 3 and Yijun He 1 ID 1 School of Marine Sciences, Nanjing University of Information Science and Technology, Nanjing 210044, Jiangsu, China; [email protected] (H.F.); [email protected] (L.Z.); [email protected] (Y.H.) 2 Fisheries & Oceans Canada, Bedford Institute of Oceanography, Dartmouth, NS B2Y 4A2, Canada; [email protected] 3 State Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, State Oceanic Administration, Hangzhou 310012, Zhejiang, China; [email protected] * Correspondence: [email protected]; Tel.: +86-255-869-5697 Received: 22 September 2017; Accepted: 13 December 2017; Published: 15 December 2017 Abstract: A total of 168 fully polarimetric synthetic-aperture radar (SAR) images are selected together with the buoy measurements of ocean surface wind fields and high-frequency radar measurements of ocean surface currents. Our objective is to investigate the effect of the ocean currents on the retrieved SAR ocean surface wind fields. The results show that, compared to SAR wind fields that are retrieved without taking into account the ocean currents, the accuracy of the winds obtained when ocean currents are taken into account is increased by 0.2–0.3 m/s; the accuracy of the wind direction is improved by 3–4◦. Based on these results, a semi-empirical formula for the errors in the winds and the ocean currents is derived.
  • Observational Studies of Scatterometer Ocean Vector Winds in the Presence of Dynamic Air-Sea Interactions

    Observational Studies of Scatterometer Ocean Vector Winds in the Presence of Dynamic Air-Sea Interactions

    University of New Hampshire University of New Hampshire Scholars' Repository Doctoral Dissertations Student Scholarship Spring 2012 Observational studies of scatterometer ocean vector winds in the presence of dynamic air-sea interactions Amanda Michael Plagge University of New Hampshire, Durham Follow this and additional works at: https://scholars.unh.edu/dissertation Recommended Citation Plagge, Amanda Michael, "Observational studies of scatterometer ocean vector winds in the presence of dynamic air-sea interactions" (2012). Doctoral Dissertations. 656. https://scholars.unh.edu/dissertation/656 This Dissertation is brought to you for free and open access by the Student Scholarship at University of New Hampshire Scholars' Repository. It has been accepted for inclusion in Doctoral Dissertations by an authorized administrator of University of New Hampshire Scholars' Repository. For more information, please contact [email protected]. OBSERVATIONAL STUDIES OF SCATTEROMETER OCEAN VECTOR WINDS IN THE PRESENCE OF DYNAMIC AIR-SEA INTERACTIONS BY AMANDA MICHAEL PLAGGE Bachelor of Arts, Dartmouth College, 2003 Bachelor of Engineering, Thayer School of Engineering, 2004 Master of Science, Dartmouth College, 2006 DISSERTATION Submitted to the University of New Hampshire in partial fulfillment of the requirements for the Degree of Doctor of Philosophy in Earth and Environmental Science: Oceanography May 2012 UMI Number: 3525064 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. UMI 3525064 Published by ProQuest LLC 2012.
  • Ocean Surface Currents Introduction to Ocean Gyres

    Ocean Surface Currents Introduction to Ocean Gyres

    Ocean Surface Currents Introduction to Ocean Gyres One of the primary goals of physical oceanography is to know the average movement of ocean water, everywhere around the globe. Besides knowing the average flow, it is also very useful to know how much this flow can change over a course of a day, over a year, over ten years, and longer. Ocean currents are organized flows that persist over some geographical region and over some time period such that water is transported from one part of the ocean to another part of the ocean. Currents also transport plankton, fish, heat, momentum, and chemicals such as salts, oxygen, and carbon dioxide. Currents are a significant component of the global biogeochemical and hydrological cycles. Knowledge of ocean currents is also extremely important for marine operations involving navigation, search and rescue at sea, and the dispersal of pollutants. It is quite evident from observations of ocean flow that the wind moves water, and that the wind is one of the primary forces that drive ocean currents. In the early part of the 20th century, a Norwegian scientist, Fridtjof Nanson, noted that icebergs in the North Atlantic moved to the right of the wind. His student, V. Walfrid Ekman, demonstrated that the earth's rotation caused this effect and in particular, that the Coriolis force was responsible and in the Southern Hemisphere, it causes water to move to the left of the wind. One of the primary results of Ekman dynamics is that the net movement of water, forced by large-scale winds, are to the right (left) of the wind in the Northern (Southern) Hemisphere.
  • Life on the Coral Reef

    Life on the Coral Reef

    Coral Reef Teacher’s Guide Life on the Coral Reef Life on the Coral Reef THE CORAL REEF ECOSYSTEM The muddy silt drifts out to sea, covering the nearby Coral reefs provide the basis for the most productive coral reefs. Some corals can remove the silt, but many shallow water ecosystem in the world. An ecosystem cannot. If the silt is not washed off within a short pe- is a group of living things, such as coral, algae and riod of time by the current, the polyps suffocate and fishes, along with their non-living environment, such die. Not only the rainforest is destroyed, but also the as rocks, water, and sand. Each influences the other, neighboring coral reef. and both are necessary for the successful maintenance of life. If one is thrown out of balance by either natural Reef Zones or human-made causes, then the survival of the other Coral reefs are not uniform, but are shaped by the is seriously threatened. forces of the sea and the structure of the sea floor into DID YOU KNOW? All of the Earth’s ecosystems are a series of different parts or reef zones. Understand- interrelated, forming a shell of life that covers the ing these zones is useful in understanding the ecol- entire planet – the biosphere. For instance, if too many ogy of coral reefs. Keep in mind that these zones can trees are cut down in the rainforest, soil from the for- blend gradually into one another, and that sometimes est is washed by rain into rivers that run to the ocean.
  • COASTAL EROSION and BEACH NOURISHMENT in SCANIA AS ISSUES in SWEDISH COASTAL POLICY Skånes Kusterosion Och Strandfodringars Roll I Svensk Kustpolicy

    COASTAL EROSION and BEACH NOURISHMENT in SCANIA AS ISSUES in SWEDISH COASTAL POLICY Skånes Kusterosion Och Strandfodringars Roll I Svensk Kustpolicy

    VATTEN – Journal of Water Management and Research 72:103–115. Lund 2016 COASTAL EROSION AND BEACH NOURISHMENT IN SCANIA AS ISSUES IN SWEDISH COASTAL POLICY Skånes kusterosion och strandfodringars roll i svensk kustpolicy by LOTTE E. BONTJE 1, CAROLINE FREDRIKSSON 2, ZILIN WANG 3, JILL H. SLINGER 1, 4 1 Delft University of Technology, Faculty of Technology, Policy and Management, Multi-Actor Systems department. P. O. Box 5015, 2600 GA Delft, The Netherlands. 2 Lund University, Faculty of Engineering (LTH), Department of Building and Environmental Technology, Division of Water Resources Engineering. Box 118, 221 00 Lund, Sweden. 3 Tianjin Academy of Environmental Sciences, No. 17 Fukang Road, Tianjin 300191, China. 4 Delft University of Technology, Faculty of Civil Engineering and Geosciences, Coastal Engineering. P. O. Box 5015, 2600 GA Delft, The Netherlands. Abstract This paper discusses the dynamics of coastal policy change in Sweden, using erosion and beach nourishments as an example. The Multiple Stream Model is a theoretical model on agenda setting and policy change devel- oped by the political scientist John Kingdon (1984, 2003). This paper applies Kingdon’s model in describing and explaining coastal policy dynamics regarding coastal erosion in Sweden. Coastal protection is not a separate policy field in Sweden: interventions to protect the (common) coast form a component of spatial planning, which is largely the responsibility of the municipalities. Our analysis reveals that interventions to protect the coast are indeed organized at a local level, by landowners and the municipality, driven by a strong problem perception. This problem perception is articulated as a local voice seeking increased acknowledgement of the coastal erosion issue by the national government.