Upwelling and Circulation Dynamics in the Southern California Current System
Upwelling and Circulation Dynamics in the Southern California Current System

Author: Caroline Ford Lowcher

Publisher:

Published: 2023

Total Pages: 0

ISBN-13:

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Southern California is part of an eastern boundary upwelling system (EBUS). This region is ecologically productive and socioeconomically significant, and how EBUS will respond to future changes in climate is of scientific and societal interest. Long-term monitoring is a key component for assessing how EBUS will be impacted by climate change and long timeseries of mooring observations are the focus of this dissertation. Anomalous poleward flow was observed in southern California prior to and during the 2014 marine heatwave and 2015 - 2016 El Niño. Prior to the El Niño, local forcing drove a strengthened wind stress curl and a more persistent Southern California Eddy (SCE). The poleward recirculation of the SCE into the Southern California Bight (SCB) brought more waters from the California Current and North Pacific Subtropical Gyre closer to the coast. During the 2015 - 2016 El Niño, remote forcing drove persistent elevated coastal sea levels which forced poleward geostrophic flows and advected tropical waters into the SCB. A volume budget was performed for southern California and this motivated developing an upwelling index. The upwelling index includes cross-shore geostrophic transport by using sea level changes right at the coast, accounting for coastal processes such as coastally trapped waves. Low-frequency upwelling anomalies indicate decreased vertical transport during the 2014 - 2016 upwelling seasons concurrent with the large-scale climate phenomenon in these years. This upwelling index is a practical tool for analyzing upwelling requiring minimal in-situ observations. The upwelling forcing is valuable for assessing the physical impact on the coastal ocean, but it may not represent the oceanic response to upwelling. Multiple physical and biogeochemical properties are used to examine the coastal oceanic response to upwelling alongside the upwelling forcing. Event statistics are calculated using the long record of in-situ measurements, in addition to investigating the low-frequency in-situ anomalies. EBUS are susceptible to harmful algal blooms and a particularly pronounced red tide is examined alongside the physical processes that supported the red tide.

Ocean Circulation and Climate
Ocean Circulation and Climate

Author: P. Ted Strub

Publisher: Elsevier Inc. Chapters

Published: 2013-10-22

Total Pages: 107

ISBN-13: 0128058633

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In this chapter, we review the physical processes that create the mean and variable circulation features along the eastern margins of the ocean basins. Rather than describing the individual systems, we describe the processes and their variability between the systems, dividing the discussion into the low-, mid- and high-latitude regions. We start with the low latitudes, since their signals often move poleward along the coastal wave guides into the midlatitudes, which are the well-known eastern boundary upwelling systems. Our treatment of the higher latitudes is limited to examples from the better-studied NE Pacific Basin (The Alaska Current).

Upwelling Systems of the World
Upwelling Systems of the World

Author: Jochen Kämpf

Publisher: Springer

Published: 2016-08-29

Total Pages: 443

ISBN-13: 3319425242

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Upwelling systems are special places in the oceans where nutrient-enriched water is brought into the euphotic zone to fuel phytoplankton blooms that, via marine food-web interactions, create the world’s richest fish resources. This book introduces the reader to the interdisciplinary science of upwelling and provides a comprehensive overview of the world’s most productive marine ecosystems in the context of climate variability, climate change and human exploitation. This material presented is suitable for undergraduate and postgraduate study or just for anyone interested to learn about the creation of life in the oceans and how this is compromised by human activities.

Measurements of Ocean Currents Across the Continental Margin Off Point Sur, California, During March 1989
Measurements of Ocean Currents Across the Continental Margin Off Point Sur, California, During March 1989

Author: Anthony J. Negron

Publisher:

Published: 1993

Total Pages: 100

ISBN-13:

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Mean currents and density were measured off Point Sur, California in March 1989 using Pegasus and CTD instruments. Velocity, temperature, salinity, and density fields are examined to discern the structure of the California and Davidson currents. Velocities measured by Pegasus are compared to flow fields derived from geostrophy. The Davidson Current flows poleward at the surface in its winter configuration despite northerly winds and coastal upwelling which normally drive the flow subsurface in the summer months.

Variations in Coastal Circulation Off Central California, Spring-Summer 1993, 1994 1995
Variations in Coastal Circulation Off Central California, Spring-Summer 1993, 1994 1995

Author: Heather A. Parker

Publisher:

Published: 1996-12-01

Total Pages: 87

ISBN-13: 9781423576617

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In situ measurements of hydrographic, wind and Acoustic Doppler Current Profiler (ADCP) data, along with satellite imagery, were collected off central California during the upwelling season of three successive years, 1993, 1994 and 1995. The survey was conducted three times in the late spring of each year within 75 km of the coastline from Point Reyes south to Cypress Point, along a region of irregular coastline and bathymetry. The upwelling circulation was found to be distinct from the California Current System and unlike circulation defined in recent conceptual models for this region. Persistent or recurring circulation features were observed throughout the upwelling season that acted as dynamic boundaries to this system. A varied response by upwelling centers in this region to a fairly uniform wind field was also observed. Water upwelled within this system is considered to recirculate and mix, retained within the system for a relatively long period of time. This long retention period of upwelled water is thought to promote the high productivity associated with coastal upwelling. The circulation patterns found in this region, and the dynamic boundaries to the principal equatorward current may represent upwelling circulation at multiple locations in this and in other eastern boundary current systems, inshore of the principal equatorward current.

Ocean Circulation and Climate
Ocean Circulation and Climate

Author: Nikolai Maximenko

Publisher: Elsevier Inc. Chapters

Published: 2013-10-22

Total Pages: 30

ISBN-13: 0128058617

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This chapter summarizes the history of and recent progress in observations of surface circulation of the ocean. The description is biased toward Lagrangian drifting buoys and satellite altimetry that, in the authors’ opinion, have revolutionized our understanding of ocean surface currents by providing a high resolution, continuous global view of mesoscale ocean “weather.” We outline the current state of the observing system and characterize geostrophic surface circulation, Ekman currents, and effects of centrifugal force and nonlinear interaction between geostrophic and Ekman currents. This general description is complemented by regional examples, detailing processes in the California Current System, off Senegal, and the Kuroshio interaction with the East and South China Seas. Applications to various tasks, in which surface currents play important role, are illustrated by model simulations of motions of marine debris, including debris generated by the 2011 tsunami in Japan. The chapter concludes with a brief discussion of the next tasks needed to improve understanding of the dynamics of the surface ocean circulation.

Ocean Modeling in an Eddying Regime
Ocean Modeling in an Eddying Regime

Author: Matthew W. Hecht

Publisher: John Wiley & Sons

Published: 2013-04-30

Total Pages: 654

ISBN-13: 1118671996

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Published by the American Geophysical Union as part of the Geophysical Monograph Series, Volume 177. This monograph is the first to survey progress in realistic simulation in a strongly eddying regime made possible by recent increases in computational capability. Its contributors comprise the leading researchers in this important and constantly evolving field. Divided into three parts Oceanographic Processes and Regimes: Fundamental Questions Ocean Dynamics and State: From Regional to Global Scale, and Modeling at the Mesoscale: State of the Art and Future Directions The volume details important advances in physical oceanography based on eddy resolving ocean modeling. It captures the state of the art and discusses issues that ocean modelers must consider in order to effectively contribute to advancing current knowledge, from subtleties of the underlying fluid dynamical equations to meaningful comparison with oceanographic observations and leading-edge model development. It summarizes many of the important results which have emerged from ocean modeling in an eddying regime, for those interested broadly in the physical science. More technical topics are intended to address the concerns of those actively working in the field.

Wind Stress and Wind Stress Curl Over the California Current
Wind Stress and Wind Stress Curl Over the California Current

Author: Craig S. Nelson

Publisher:

Published: 1976

Total Pages: 292

ISBN-13:

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Historical surface marine observations are summarized by 1-degree square area and long term month to describe the seasonal distribution of wind stress over the California Current. Off the coasts of southern California and Baja California, an alongshore equatorward component is present throughout the year. The distributions north of Cape Mendocino are characterized by marked changes in direction and magnitude between summer and winter. The predominant wind stress maximum shifts northward coherently from off Point Conception in March to south of Cape Blanco in September, and extends approximately 500 km in the offshore direction and 1000 km in the alongshore direction. Maximum values of surface wind stress occur during July near Cape Mendocino. The wind stress curl is positive near the coast and negative in the region offshore.

Introduction to Ocean Circulation and Modeling
Introduction to Ocean Circulation and Modeling

Author: Avijit Gangopadhyay

Publisher: CRC Press

Published: 2022-02-14

Total Pages: 528

ISBN-13: 1000539059

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Introduction to Ocean Circulation and Modeling provide basics for physical oceanography covering ocean properties, ocean circulations and their modeling. First part of the book explains concepts of oceanic circulation, geostrophy, Ekman, Sverdrup dynamics, Stommel and Munk problems, two-layer dynamics, stratification, thermal and salt diffusion, vorticity/instability, and so forth. Second part highlights basic implementation framework for ocean models, discussion of different models, and their unique differences from the common framework with basin-scale modeling, regional modeling, and interdisciplinary modeling at different space and time scales. Features: Covers ocean properties, ocean circulations and their modeling. Explains the centrality of a rotating earth and its implications for ocean and atmosphere in a simple manner. Provides basic facts of ocean dynamics. Illustrative diagrams for clear understanding of key concepts. Outlines interdisciplinary and complex models for societal applications. The book aims at Senior Undergraduate Students, Graduate Students and Researchers in Ocean Science and Engineering, Ocean Technology, Physical Oceanography, Ocean Circulation, Ocean Modeling, Dynamical Oceanography and Earth Science.