Deep and Surface Circulation in the Northwest Indian Ocean from Argo, Surface Drifter, Satellite, and in Situ Profiling Current Observations

Deep and Surface Circulation in the Northwest Indian Ocean from Argo, Surface Drifter, Satellite, and in Situ Profiling Current Observations PDF Author: Sarah Stryker
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Book Description
The physical oceanography in the northwest Indian Ocean is largely controlled by the seasonal monsoon. The seasonal variability in circulation is complex. Many studies have investigated processes in the Persian (Arabian) Gulf and Arabian Sea, but little is understood about the Sea of Oman. This thesis incorporated observations from Argo floats, surface drifters and satellite imagery to study the deep and surface circulation in the northwest Indian Ocean. An assessment of four independent moorings located in the Sea of Oman and Arabian Sea, as well as a model skill comparison of the Simple Ocean Data Assimilation (SODA) model, contributed to understanding the dynamics in this region. Spatial patterns of surface current velocity produced from surface drifter data from 1995-2009 agreed with previously known surface currents. The Somali Current, East Arabian Current, Equatorial Current, Northeast/Southwest Monsoon Current, Great Whirl and Ras al Hadd Jet were all identified. During the Southwest Monsoon, flow direction was to the east and southeast in the Arabian Sea. The Somali Current flowed northeast along the Somali Coast extending to the East Arabian Current along the Oman coast. During the Northeast Monsoon, evaporation increased over the Arabian Sea, which resulted in a salinity gradient. This imbalance caused low-salinity surface water from the northeast Indian Ocean to flow into the northwest Indian Ocean as the Northeast Monsoon Current. Current direction reversed with the change of wind direction from the Southwest Monsoon to the Northwest Monsoon. Many characteristics seen at the surface were also identified in the subsurface as deep as 1500m. The comparison of moored observations to the Argo observations co-located in space and time showed reasonable agreement with the largest salinity difference of 0.23 and largest temperature difference of 0.78?C. The Murray Ridge mooring had a temperature correlation of 0.97 when compared to Argo observations. Argo observations were compared with SODA model numerical output from 1992-2001, and, after Argo, were assimilated from 2002-2009. With assimilation of Argo data into the SODA model, the temperature and salinity from the model numerical output improved, with most differences between model numerical output and Argo observations falling within one standard deviation.

Deep and Surface Circulation in the Northwest Indian Ocean from Argo, Surface Drifter, Satellite, and in Situ Profiling Current Observations

Deep and Surface Circulation in the Northwest Indian Ocean from Argo, Surface Drifter, Satellite, and in Situ Profiling Current Observations PDF Author: Sarah Stryker
Publisher:
ISBN:
Category :
Languages : en
Pages :

Get Book Here

Book Description
The physical oceanography in the northwest Indian Ocean is largely controlled by the seasonal monsoon. The seasonal variability in circulation is complex. Many studies have investigated processes in the Persian (Arabian) Gulf and Arabian Sea, but little is understood about the Sea of Oman. This thesis incorporated observations from Argo floats, surface drifters and satellite imagery to study the deep and surface circulation in the northwest Indian Ocean. An assessment of four independent moorings located in the Sea of Oman and Arabian Sea, as well as a model skill comparison of the Simple Ocean Data Assimilation (SODA) model, contributed to understanding the dynamics in this region. Spatial patterns of surface current velocity produced from surface drifter data from 1995-2009 agreed with previously known surface currents. The Somali Current, East Arabian Current, Equatorial Current, Northeast/Southwest Monsoon Current, Great Whirl and Ras al Hadd Jet were all identified. During the Southwest Monsoon, flow direction was to the east and southeast in the Arabian Sea. The Somali Current flowed northeast along the Somali Coast extending to the East Arabian Current along the Oman coast. During the Northeast Monsoon, evaporation increased over the Arabian Sea, which resulted in a salinity gradient. This imbalance caused low-salinity surface water from the northeast Indian Ocean to flow into the northwest Indian Ocean as the Northeast Monsoon Current. Current direction reversed with the change of wind direction from the Southwest Monsoon to the Northwest Monsoon. Many characteristics seen at the surface were also identified in the subsurface as deep as 1500m. The comparison of moored observations to the Argo observations co-located in space and time showed reasonable agreement with the largest salinity difference of 0.23 and largest temperature difference of 0.78?C. The Murray Ridge mooring had a temperature correlation of 0.97 when compared to Argo observations. Argo observations were compared with SODA model numerical output from 1992-2001, and, after Argo, were assimilated from 2002-2009. With assimilation of Argo data into the SODA model, the temperature and salinity from the model numerical output improved, with most differences between model numerical output and Argo observations falling within one standard deviation.

The Indian Ocean and its Role in the Global Climate System

The Indian Ocean and its Role in the Global Climate System PDF Author: Caroline C. Ummenhofer
Publisher: Elsevier
ISBN: 0128232862
Category : Science
Languages : en
Pages : 514

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Book Description
The Indian Ocean and its Role in the Global Climate System provides an overview of our contemporary understanding of the Indian Ocean (geology, atmosphere, ocean, hydrology, biogeochemistry) and its role in the climate system. It describes the monsoon systems, Indian Ocean circulation and connections with other ocean basins. Climatic phenomena in the Indian Ocean are detailed across a range of timescales (seasonal, interannual to multi-decadal). Biogeochemical and ecosystem variability is also described. The book will provide a summary of different tools (e.g., observations, modeling, paleoclimate records) that are used for understanding Indian Ocean variability and trends. Recent trends and future projections of the Indian Ocean, including warming, extreme events, ocean acidification and deoxygenation will be detailed. The Indian Ocean is unique and different from other tropical ocean basins due to its geography. It is traditionally under-observed and understudied, yet plays a fundamental role for regional and global climate. The vagaries of the Asian monsoon affect over a billion people and a third of the global population live in the vicinity of the Indian Ocean. It is also particularly vulnerable to climate change, with robust warming and trends in heat and freshwater observed in recent decades. Advances have recently been made in our understanding of the Indian Ocean’s circulation, interactions with adjacent ocean basins, and its role in regional and global climate. Nonetheless, significant gaps remain in understanding, observing, modeling, and predicting Indian Ocean variability and change across a range of timescales. As such, this book is the perfect compendium to any researcher, student, teacher/lecturer in the fields of oceanography, atmospheric science, paleoclimate, environmental science, meteorology and geology, as well as policy managers and water resource managers. Provides interdisciplinary content with a comprehensive overview for students and practitioners from a wide range of disciplines as well as for stakeholders Presents a broad overview and background on the current state of knowledge of the variability, change, and regional impacts of the Indian Ocean Includes links to animations, slideshows, and other educational resources

Field Measurements for Passive Environmental Remote Sensing

Field Measurements for Passive Environmental Remote Sensing PDF Author: Nicholas R. Nalli
Publisher: Elsevier
ISBN: 0128242264
Category : Science
Languages : en
Pages : 454

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Book Description
Field Measurements for Environmental Remote Sensing: Instrumentation, Intensive Campaigns, and Satellite Applications is an academic synthesis of invaluable in situ measurements and techniques leveraged by the science of environmental remote sensing. Sections cover in situ datasets and observing methods used for satellite remote sending applications and validation, synthesizing the various techniques utilized by well-established application areas under a common paradigm. The book serves as both a textbook for students (upper-level undergraduate to graduate level) and a reference book for practitioners and researchers in the atmospheric, oceanic and remote sensing fields. Presents chapters organized according to subdiscipline, with each written by established experts in their relevant field Includes literature reviews, case studies and applications for each subdivision Features a synthesis of the suite of invaluable in situ measurements and techniques leveraged by the science of environmental remote sensing

Interacting Climates of Ocean Basins

Interacting Climates of Ocean Basins PDF Author: Carlos R. Mechoso
Publisher: Cambridge University Press
ISBN: 1108492703
Category : Science
Languages : en
Pages : 359

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Book Description
A comprehensive review of interactions between the climates of different ocean basins and their key contributions to global climate variability and change. Providing essential theory and discussing outstanding examples as well as impacts on monsoons, it a useful resource for graduate students and researchers in the atmospheric and ocean sciences.

Special Catalogue of Data from the International Indian Ocean Expedition

Special Catalogue of Data from the International Indian Ocean Expedition PDF Author: IGY World Data Center A--Oceanography
Publisher:
ISBN:
Category : Exchange of oceanographic information
Languages : en
Pages : 304

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Book Description


Satellite Observations of the Influence of Mesoscale Ocean Eddies on Near-surface Temperature, Phytoplankton and Surface Stress

Satellite Observations of the Influence of Mesoscale Ocean Eddies on Near-surface Temperature, Phytoplankton and Surface Stress PDF Author: Peter Gaube
Publisher:
ISBN:
Category : Eddies
Languages : en
Pages : 197

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Book Description
The influence of mesoscale ocean eddies on near-surface ocean temperature, surface stress and phytoplankton communities is investigated by collocating numerous satellite measurements along with vertical profiles of oceanic temperature and salinity to the interiors of eddies identified and tracked in altimetric sea surface height maps. The surface currents associated with mesoscale ocean eddies impart a curl of the surface stress from the relative motion between surface air and water. This stress curl has a polarity opposite that of the vorticity of the eddy, thus attenuating the eddies by generating Ekman upwelling in the cores of anticyclones and downwelling in the cores of cyclones. Ekman pumping also arises from eddy-induced spatial variability of the sea surface temperature (SST) field that generates a wind stress curl in regions of crosswind SST gradients through a response of surface winds to SST-induced surface heating variations. SST-induced Ekman pumping is shown to be secondary to surface current-induced pumping in most regions of the World Ocean. Eddy-induced Ekman pumping resulting from the combination of surface current effects and air-sea interaction represents an order 1 perturbation of the background, basin-scale Ekman pumping velocities from the large-scale wind fields. In western boundary currents and equatorward-flowing eastern boundary currents, cyclonic eddies preferentially entrain water from the coastal side of the boundary current, which primes the interiors of cyclones to have phytoplankton concentrations that are elevated relative to the background. In contrast, anticyclones formed in these regions contain locally depressed phytoplankton concentrations from the offshore waters. While eddy pumping from vertical displacements of isopycnals during eddy formation can affect the biology in the interiors of cyclones during the transient stage of their development, this ecosystem response cannot be sustained because of the persistent eddy-induced Ekman downwelling throughout the rest of the eddy lifetimes. Likewise, the persistent eddy-induced Ekman upwelling in anticyclones is of little benefit because of their low phytoplankton content at the time of formation. A definitive response to eddy pumping is therefore difficult to detect from satellite observations alone. Eddies formed in regions where anticyclones preferentially entrain water with elevated phytoplankton concentrations, such as the South Indian Ocean, or in some mid-ocean gyre regions where small-amplitude eddies form (e.g., the oligotrophic South Pacific), an ecosystem response to eddy-induced Ekman pumping is observed. Conversely, cyclones in these regions entrain water that is low in chlorophyll, resulting in negative chlorophyll anomalies that are sustained by Ekman downwelling throughout the eddy lifetimes. The phytoplankton response to eddy-induced Ekman upwelling in anticyclones is seasonal, occurring only during the winter. It is proposed that the mechanism for the lack of ecosystem response to eddy-induced Ekman upwelling during the summer is the decoupling of the mixed layer from the nutricline. The observations presented in this dissertation provide a baseline from which coupled ocean circulation and biogeochemical models can be assessed. If coupled models are able to reproduce correctly the observed influence of mesoscale eddies on photoautotrophic communities, further insight into the mechanisms for this variability could be gained from the model output using the methodologies developed in this dissertation together with investigation of subsurface variability in the models below the depth to which chlorophyll can be inferred from the satellite observations.

Argo

Argo PDF Author: Peter Gwynne
Publisher:
ISBN:
Category : Climatic changes
Languages : en
Pages : 20

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A study of the indian ocean circulation using satellite observations and model simulations

A study of the indian ocean circulation using satellite observations and model simulations PDF Author: Bulusu Subrahmanyam
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Real-time Coastal Observing Systems for Marine Ecosystem Dynamics and Harmful Algal Blooms

Real-time Coastal Observing Systems for Marine Ecosystem Dynamics and Harmful Algal Blooms PDF Author: Babin, Marcel
Publisher: UNESCO
ISBN: 9231040421
Category : Nature
Languages : en
Pages : 880

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Book Description
The proliferation of harmful phytoplankton in marine ecosystems can cause massive fish kills, contaminate seafood with toxins, impact local and regional economies and dramatically affect ecological balance. Real-time observations are essential for effective short-term operational forecasting, but observation and modelling systems are still being developed. This volume provides guidance for developing real-time and near real-time sensing systems for observing and predicting plankton dynamics, including harmful algal blooms, in coastal waters. The underlying theory is explained and current trends in research and monitoring are discussed.Topics covered include: coastal ecosystems and dynamics of harmful algal blooms; theory and practical applications of in situ and remotely sensed optical detection of microalgal distributions and composition; theory and practical applications of in situ biological and chemical sensors for targeted species and toxin detection; integrated observing systems and platforms for detection; diagnostic and predictive modelling of ecosystems and harmful algal blooms, including data assimilation techniques; observational needs for the public and government; and future directions for research and operations.

Oceanic Abstracts with Indexes

Oceanic Abstracts with Indexes PDF Author:
Publisher:
ISBN:
Category : Marine biology
Languages : en
Pages : 574

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Book Description