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Full-Text Articles in Physical Sciences and Mathematics

Delayed Coastal Inundations Caused By Ocean Dynamics Post-Hurricane Matthew, Kyungmin Park, Emanuele Di Lorenzo, Yinglong J. Zhang, Tal Ezer, Fei Yi Jan 2024

Delayed Coastal Inundations Caused By Ocean Dynamics Post-Hurricane Matthew, Kyungmin Park, Emanuele Di Lorenzo, Yinglong J. Zhang, Tal Ezer, Fei Yi

CCPO Publications

Post Hurricane Abnormal Water Level (PHAWL) poses a persistent inundation threat to coastal communities, yet unresolved knowledge gaps exist regarding its spatiotemporal impacts and causal mechanisms. Using a high-resolution coastal model with a set of observations, we find that the PHAWLs are up to 50 cm higher than the normal water levels for several weeks and cause delayed inundations around residential areas of the U.S. Southeast Coast (USSC). Numerical experiments reveal that while atmospheric forcing modulates the coastal PHAWLs, ocean dynamics primarily driven by the Gulf Stream control the mean component and duration of the shelf-scale PHAWLs. Because of the …


On The Links Between Sea Level And Temperature Variations In The Chesapeake Bay And The Atlantic Meridional Overturning Circulation (Amoc), Tal Ezer, Teresa Updyke Jan 2024

On The Links Between Sea Level And Temperature Variations In The Chesapeake Bay And The Atlantic Meridional Overturning Circulation (Amoc), Tal Ezer, Teresa Updyke

CCPO Publications

Recent studies found that on long time scales there are often unexplained opposite trends in sea level variability between the upper and lower Chesapeake Bay (CB). Therefore, daily sea level and temperature records were analyzed in two locations, Norfolk in the southern CB and Baltimore in the northern CB; surface currents from Coastal Ocean Dynamics Application Radar (CODAR) near the mouth of CB were also analyzed to examine connections between the CB and the Atlantic Ocean. The observations in the bay were compared with daily Atlantic Meridional Overturning Circulation (AMOC) observations during 2005–2021. Empirical Mode Decomposition (EMD) analysis was used …


Last Millennium Hurricane Activity Linked To Endogenous Climate Variability, Wenchang Yang, Elizabeth Wallace, Gabriel A. Vecchi, Jeffrey P. Donnelly, Julien Emile-Geay, Gregory J. Hakim, Larry W. Horowitz, Richard M. Sullivan, Robert Tardif, Peter J. Van Hengstum, Tyler S. Winkler Jan 2024

Last Millennium Hurricane Activity Linked To Endogenous Climate Variability, Wenchang Yang, Elizabeth Wallace, Gabriel A. Vecchi, Jeffrey P. Donnelly, Julien Emile-Geay, Gregory J. Hakim, Larry W. Horowitz, Richard M. Sullivan, Robert Tardif, Peter J. Van Hengstum, Tyler S. Winkler

OES Faculty Publications

Despite increased Atlantic hurricane risk, projected trends in hurricane frequency in the warming climate are still highly uncertain, mainly due to short instrumental record that limits our understanding of hurricane activity and its relationship to climate. Here we extend the record to the last millennium using two independent estimates: a reconstruction from sedimentary paleohurricane records and a statistical model of hurricane activity using sea surface temperatures (SSTs). We find statistically significant agreement between the two estimates and the late 20th century hurricane frequency is within the range seen over the past millennium. Numerical simulations using a hurricane-permitting climate model suggest …


Acceleration Of U.S. Southeast And Gulf Coast Sea-Level Rise Amplified By Internal Climate Variability, Sönke Dangendorf, Noah Hendricks, Qiang Sun, John Klinck, Tal Ezer, Thomas Frederikse, Francisco M. Calafat, Thomas Wahl, Torbjörn E. Törnqvist Jan 2023

Acceleration Of U.S. Southeast And Gulf Coast Sea-Level Rise Amplified By Internal Climate Variability, Sönke Dangendorf, Noah Hendricks, Qiang Sun, John Klinck, Tal Ezer, Thomas Frederikse, Francisco M. Calafat, Thomas Wahl, Torbjörn E. Törnqvist

CCPO Publications

While there is evidence for an acceleration in global mean sea level (MSL) since the 1960s, its detection at local levels has been hampered by the considerable influence of natural variability on the rate of MSL change. Here we report a MSL acceleration in tide gauge records along the U.S. Southeast and Gulf coasts that has led to rates (>10 mm yr−1 since 2010) that are unprecedented in at least 120 years. We show that this acceleration is primarily induced by an ocean dynamic signal exceeding the externally forced response from historical climate model simulations. However, when the …


A Global Comparison Of Marine Chlorophyll Variability Observed In Eulerian And Lagrangian Perspectives, Angela M. Kuhn, Matthew Mazloff, Stephanie Dutkiewicz, Oliver Jahn, Sophie Clayton, Tatiana Rynearson, Andrew D. Barton Jan 2023

A Global Comparison Of Marine Chlorophyll Variability Observed In Eulerian And Lagrangian Perspectives, Angela M. Kuhn, Matthew Mazloff, Stephanie Dutkiewicz, Oliver Jahn, Sophie Clayton, Tatiana Rynearson, Andrew D. Barton

OES Faculty Publications

The California Current System is a diatom‐dominated region characterized by seasonal coastal upwelling and additional elevated mesoscale activity. Cyclonic mesoscale eddies in the region trap productive coastal waters with their planktonic communities and transport them offshore with limited interaction with surrounding waters, effectively acting as natural mesocosms, where phytoplankton populations undergo ecological succession as eddies age. This study examines diatom community composition within two mesoscale cyclonic eddies that formed in the same region of the California Current System 2 months apart and in the California Current waters surrounding them. The diatom communities were analyzed in the context of shifting environmental …


Pore Water Exchange-Driven Inorganic Carbon Export From Intertidal Salt Marshes, Joeseph J. Tamborski, Meagan Eagle, Barret L. Kurylyk, Kevin D. Kroeger, Zhaoihui Aleck Wang, Paul Henderson, Matthew A. Charette Jan 2021

Pore Water Exchange-Driven Inorganic Carbon Export From Intertidal Salt Marshes, Joeseph J. Tamborski, Meagan Eagle, Barret L. Kurylyk, Kevin D. Kroeger, Zhaoihui Aleck Wang, Paul Henderson, Matthew A. Charette

OES Faculty Publications

Respiration in intertidal salt marshes generates dissolved inorganic carbon (DIC) that is exported to the coastal ocean by tidal exchange with the marsh platform. Understanding the link between physical drivers of water exchange and chemical flux is a key to constraining coastal wetland contributions to regional carbon budgets. The spatial and temporal (seasonal, annual) variability of marsh pore water exchange and DIC export was assessed from a microtidal salt marsh (Sage Lot Pond, Massachusetts). Spatial variability was constrained from 224Ra : 228Th disequilibria across two hydrologic units within the marsh sediments. Disequilibrium between the more soluble 224Ra …


Closing The Oxygen Mass Balance In Shallow Coastal Ecosystems, Matthew H. Long, Jennie E. Rheuban, Daniel C. Mccorkle, David J. Burdige, Richard C. Zimmerman Nov 2019

Closing The Oxygen Mass Balance In Shallow Coastal Ecosystems, Matthew H. Long, Jennie E. Rheuban, Daniel C. Mccorkle, David J. Burdige, Richard C. Zimmerman

OES Faculty Publications

The oxygen concentration in marine ecosystems is influenced by production and consumption in the water column and fluxes across both the atmosphere-water and benthic-water boundaries. Each of these fluxes has the potential to be significant in shallow ecosystems due to high fluxes and low water volumes. This study evaluated the contributions of these three fluxes to the oxygen budget in two contrasting ecosystems, a Zostera marina (eelgrass) meadow in Virginia, U.S.A., and a coral reef in Bermuda. Benthic oxygen fluxes were evaluated by eddy covariance. Water column oxygen production and consumption were measured using an automated water incubation system. Atmosphere-water …


Estuarine Dissolved Organic Carbon Flux From Space: With Application To Chesapeake And Delaware Bays, Sergio R. Signorini, Antonio Mannino, Marjorie A.M. Friedrichs, Pierre St-Laurent, John Wilkin, Aboozar Tabatabai, Raymond G. Najjar, Eileen E. Hofmann, Fei Da, Hanqin Tian, Yuanzhi Yao Jun 2019

Estuarine Dissolved Organic Carbon Flux From Space: With Application To Chesapeake And Delaware Bays, Sergio R. Signorini, Antonio Mannino, Marjorie A.M. Friedrichs, Pierre St-Laurent, John Wilkin, Aboozar Tabatabai, Raymond G. Najjar, Eileen E. Hofmann, Fei Da, Hanqin Tian, Yuanzhi Yao

CCPO Publications

This study uses a neural network model trained with in situ data, combined with satellite data and hydrodynamic model products, to compute the daily estuarine export of dissolved organic carbon (DOC) at the mouths of Chesapeake Bay (CB) and Delaware Bay (DB) from 2007 to 2011. Both bays show large flux variability with highest fluxes in spring and lowest in fall as well as interannual flux variability (0.18 and 0.27 Tg C/year in 2008 and 2010 for CB; 0.04 and 0.09 Tg C/year in 2008 and 2011 for DB). Based on previous estimates of total organic carbon (TOCexp) exported by …


The Tides They Are A-Changin': A Comprehensive Review Of Past And Future Nonastronomical Changes In Tides, Their Driving Mechanisms, And Future Implications, Ivan D. Haigh, Mark D. Pickering, J. A. Mattias Green, Brian K. Arbic, Arne Arns, Sönke Dangendorf, David F. Hill, Kevin Horsburgh, Tom Howard, Déborah Idier, David A. Jay, Leon Jänicke, Serena B. Lee, Malte Müller, Michael Schindelegger, Stefan A. Talke, Sophie-Berenice Wilmes, Philip L. Woodworth Jan 2019

The Tides They Are A-Changin': A Comprehensive Review Of Past And Future Nonastronomical Changes In Tides, Their Driving Mechanisms, And Future Implications, Ivan D. Haigh, Mark D. Pickering, J. A. Mattias Green, Brian K. Arbic, Arne Arns, Sönke Dangendorf, David F. Hill, Kevin Horsburgh, Tom Howard, Déborah Idier, David A. Jay, Leon Jänicke, Serena B. Lee, Malte Müller, Michael Schindelegger, Stefan A. Talke, Sophie-Berenice Wilmes, Philip L. Woodworth

CCPO Publications

Scientists and engineers have observed for some time that tidal amplitudes at many locations are shifting considerably due to nonastronomical factors. Here we review comprehensively these important changes in tidal properties, many of which remain poorly understood. Over long geological time scales, tectonic processes drive variations in basin size, depth, and shape and hence the resonant properties of ocean basins. On shorter geological time scales, changes in oceanic tidal properties are dominated by variations in water depth. A growing number of studies have identified widespread, sometimes regionally coherent, positive, and negative trends in tidal constituents and levels during the 19th, …


The Dominant Global Modes Of Recent Internal Sea Level Variability, Benjamin Dillon Hamlington, Se-Hyeon Cheon, Christopher G. Piecuch, Kristopher B. Karnauskas, Philip R. Thompson, Kwang-Yul Kim, John Thomas Reager, Felix W. Landerer, Thomas Frederikse Jan 2019

The Dominant Global Modes Of Recent Internal Sea Level Variability, Benjamin Dillon Hamlington, Se-Hyeon Cheon, Christopher G. Piecuch, Kristopher B. Karnauskas, Philip R. Thompson, Kwang-Yul Kim, John Thomas Reager, Felix W. Landerer, Thomas Frederikse

OES Faculty Publications

The advances in the modern sea level observing system have allowed for a new level of knowledge of regional and global sea level in recent years. The combination of data from satellite altimeters, Gravity Recovery and Climate Experiment (GRACE) satellites, and Argo profiling floats has provided a clearer picture of the different contributors to sea level change, leading to an improved understanding of how sea level has changed in the present and, by extension, may change in the future. As the overlap between these records has recently extended past a decade in length, it is worth examining the extent to …


High Frequency Temperature Variability Reduces The Risk Of Coral Bleaching, Aryan Safaie, Nyssa J. Silbiger, Timothy R. Mcclanahan, Geno Pawlak, Daniel J. Barshis, James L. Hench, Gareth J. Williams, Kristen A. Davis Jan 2018

High Frequency Temperature Variability Reduces The Risk Of Coral Bleaching, Aryan Safaie, Nyssa J. Silbiger, Timothy R. Mcclanahan, Geno Pawlak, Daniel J. Barshis, James L. Hench, Gareth J. Williams, Kristen A. Davis

Biological Sciences Faculty Publications

Coral bleaching is the detrimental expulsion of algal symbionts from their cnidarian hosts, and predominantly occurs when corals are exposed to thermal stress. The incidence and severity of bleaching is often spatially heterogeneous within reef-scales (km), and is therefore not predictable using conventional remote sensing products. Here, we systematically assess the relationship between in situ measurements of 20 environmental variables, along with seven remotely sensed SST thermal stress metrics, and 81 observed bleaching events at coral reef locations spanning five major reef regions globally. We find that high-frequency temperature variability (i.e., daily temperature range) was the most influential factor in …


Imber- Research For Marine Sustainability: Synthesis And The Way Forward, Eileen Hofmann, Alida Bundy, Ken Drinkwater, Alberto R. Piola, Bernard Avril, Carol Robinson Jan 2015

Imber- Research For Marine Sustainability: Synthesis And The Way Forward, Eileen Hofmann, Alida Bundy, Ken Drinkwater, Alberto R. Piola, Bernard Avril, Carol Robinson

CCPO Publications

The Integrated Marine Biogeochemistry and Ecosystem Research (IMBER) project aims at developing a comprehensive understanding of and accurate predictive capacity of ocean responses to accelerating global change and the consequent effects on the Earth system and human society. Understanding the changing ecology and biogeochemistry of marine ecosystems and their sensitivity and resilience to multiple drivers, pressures and stressors is critical to developing responses that will help reduce the vulnerability of marine-dependent human communities. This overview of the IMBER project provides a synthesis of project achievements and highlights the value of collaborative, interdisciplinary, integrated research approaches as developed and implemented through …


Predicting Carbon Isotope Discrimination In Eelgrass (Zostera Marina L.) From The Environmental Parameters- Light, Flow, And [Dic], Meredith L. Mcpherson, Richard C. Zimmerman, Victoria J. Hill Jan 2015

Predicting Carbon Isotope Discrimination In Eelgrass (Zostera Marina L.) From The Environmental Parameters- Light, Flow, And [Dic], Meredith L. Mcpherson, Richard C. Zimmerman, Victoria J. Hill

OES Faculty Publications

Isotopic discrimination against 13C during photosynthesis is determined by a combination of environmental conditions and physiological mechanisms that control delivery of CO2 to RUBISCO. This study investigated the effects of light, flow, dissolved inorganic carbon (DIC) concentration, and its speciation, on photosynthetic carbon assimilation of Zostera marinaL. (eelgrass) using a combination of laboratory experiments and theoretical calculations leading to a mechanistic understanding of environmental conditions that influence leaf carbon uptake and determine leaf stable carbon isotope signatures δ13C. Photosynthesis was saturated with respect to flow at low velocity ~ 3 cm s-1, but …


Sea Level Trends In Southeast Asian Seas, M. W. Strassburg, B. D. Hamlington, R. R. Manrung, J. Lumban-Gaol, B. Nababan, K.-Y. Kim Jan 2015

Sea Level Trends In Southeast Asian Seas, M. W. Strassburg, B. D. Hamlington, R. R. Manrung, J. Lumban-Gaol, B. Nababan, K.-Y. Kim

CCPO Publications

Southeast Asian seas span the largest archipelago in the global ocean and provide a complex oceanic pathway connecting the Pacific and Indian oceans. The Southeast Asian sea regional sea level trends are some of the highest observed in the modern satellite altimeter record that now spans almost 2 decades. Initial comparisons of global sea level reconstructions find that 17-year sea level trends over the past 60 years exhibit good agreement with decadal variability associated with the Pacific Decadal Oscillation and related fluctuations of trade winds in the region. The Southeast Asian sea region exhibits sea level trends that vary dramatically …


Drift Corrected Trends And Periodic Variations In Mipas Imk/Iaa Ozone Measurements, E. Eckert, T. Von Clarmann, M. Kiefer, G. P. Stiller, S. Lossow, N. Glatthor, D. A. Degenstein, L. Froidevaux, S. Godin-Beekmann, T. Leblanc, S. Mcdermid, M. Pastel, W. Steinbrcht, D.P.J. Swart, K. A. Walker, P. F. Bernath Jan 2014

Drift Corrected Trends And Periodic Variations In Mipas Imk/Iaa Ozone Measurements, E. Eckert, T. Von Clarmann, M. Kiefer, G. P. Stiller, S. Lossow, N. Glatthor, D. A. Degenstein, L. Froidevaux, S. Godin-Beekmann, T. Leblanc, S. Mcdermid, M. Pastel, W. Steinbrcht, D.P.J. Swart, K. A. Walker, P. F. Bernath

Chemistry & Biochemistry Faculty Publications

Drifts, trends and periodic variations were calculated from monthly zonally averaged ozone profiles. The ozone profiles were derived from level-1b data of the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) by means of the scientific level-2 processor run by the Karlsruhe Institute of Technology (KIT), Institute for Meteorology and Climate Research (IMK). All trend and drift analyses were performed using a multilinear parametric trend model which includes a linear term, several harmonics with period lengths from 3 to 24 months and the quasi-biennial oscillation (QBO). Drifts at 2-sigma significance level were mainly negative for ozone relative to Aura MLS and …


The Great 2012 Arctic Ocean Summer Cyclone Enhanced Biological Productivity On The Shelves, Jinlun Zhang, Carin Ashjian, Robert Campbell, Victoria Hill, Yvette H. Spitz, Michael Steele Jan 2014

The Great 2012 Arctic Ocean Summer Cyclone Enhanced Biological Productivity On The Shelves, Jinlun Zhang, Carin Ashjian, Robert Campbell, Victoria Hill, Yvette H. Spitz, Michael Steele

OES Faculty Publications

A coupled biophysical model is used to examine the impact of the great Arctic cyclone of early August 2012 on the marine planktonic ecosystem in the Pacific sector of the Arctic Ocean (PSA). Model results indicate that the cyclone influences the marine planktonic ecosystem by enhancing productivity on the shelves of the Chukchi, East Siberian, and Laptev seas during the storm. Although the cyclone's passage in the PSA lasted only a few days, the simulated biological effects on the shelves last 1 month or longer. At some locations on the shelves, primary productivity (PP) increases by up to 90% and …


Sea Level Rise, Spatially Uneven And Temporally Unsteady: Why The U.S. East Coast, The Global Tide Gauge Record, And The Global Altimeter Data Show Different Trends, Tal Ezer Oct 2013

Sea Level Rise, Spatially Uneven And Temporally Unsteady: Why The U.S. East Coast, The Global Tide Gauge Record, And The Global Altimeter Data Show Different Trends, Tal Ezer

CCPO Publications

Impacts of ocean dynamics on spatial and temporal variations in sea level rise (SLR) along the U.S. East Coast are characterized by empirical mode decomposition analysis and compared with global SLR. The findings show a striking latitudinal SLR pattern. Sea level acceleration consistent with a weakening Gulf Stream is maximum just north of Cape Hatteras and decreasing northward, while SLR driven by multidecadal variations, possibly from climatic variations in subpolar regions, is maximum in the north and decreasing southward. The combined impact of sea level acceleration and multidecadal variations explains why the global mean SLR obtained from similar to 20 …


Is Sea Level Rise Accelerating In The Chesapeake Bay? A Demonstation Of A Novel New Approach For Analyzing Sea Level Data, Tal Ezer, William Bryce Corlett Oct 2012

Is Sea Level Rise Accelerating In The Chesapeake Bay? A Demonstation Of A Novel New Approach For Analyzing Sea Level Data, Tal Ezer, William Bryce Corlett

CCPO Publications

Sea level data from the Chesapeake Bay are used to test a novel new analysis method for studies of sea level rise (SLR). The method, based on Empirical Mode Decomposition and Hilbert-Huang Transformation, separates the sea level trend from other oscillating modes and reveals how the mean sea level changes over time. Bootstrap calculations test the robustness of the method and provide confidence levels. The analysis shows that rates of SLR have increased from similar to 1-3 mm y(-1) in the 1930s to similar to 4-10 mm y(-1) in 2011, an acceleration of similar to 0.05-0.10 mm y(-2) that is …


The Ross Sea: In A Sea Of Change, Walker O. Smith, Peter N. Sedwick, Kevin R. Arrigo, David G. Ainley, Alejandro H. Orsi Sep 2012

The Ross Sea: In A Sea Of Change, Walker O. Smith, Peter N. Sedwick, Kevin R. Arrigo, David G. Ainley, Alejandro H. Orsi

OES Faculty Publications

The Ross Sea, the most productive region in the Antarctic, reaches farther south than any body of water in the world. While its food web is relatively intact, its oceanography, biogeochemistry, and sea ice coverage have been changing dramatically, and likely will continue to do so in the future. Sea ice cover and persistence have been increasing, in contrast to the Amundsen-Bellingshausen sector, which has resulted in reduced open water duration for its biota. Models predict that as the ozone hole recovers, ice cover will begin to diminish. Currents on the continental shelf will likely change in the coming century, …


Analysis Of Relative Sea Level Variations And Trends In The Chesapeake Bay: Is There Evidence For Acceleration In Sea Level Rise?, Tal Ezer, William B. Corlett Jan 2012

Analysis Of Relative Sea Level Variations And Trends In The Chesapeake Bay: Is There Evidence For Acceleration In Sea Level Rise?, Tal Ezer, William B. Corlett

CCPO Publications

Over the past few decades the pace of relative sea level rise (SLR) in the Chesapeake Bay (CB) has been 2-3 times faster than that of the globally mean absolute sea level. Our study is part of ongoing research that tries to determine if this SLR trend is continuing at the same pace, slowing down (SLR deceleration) or speeding up (SLR acceleration). We introduce a new analysis method for sea level data that is based on Empirical Mode Decomposition (EMD) and Hilbert-Huang Transform (HHT); the analysis separates the SLR trend from other oscillating modes of different scales. Bootstrap calculations using …


The Role Of The Alaskan Stream In Modulating The Bering Sea Climate, Tal Ezer, Lie-Yauw Oey Apr 2010

The Role Of The Alaskan Stream In Modulating The Bering Sea Climate, Tal Ezer, Lie-Yauw Oey

CCPO Publications

A numerical ocean circulation model with realistic topography, but with an idealized forcing that includes only lateral transports is used to study the role of the Alaskan Stream (AS) in modulating the Bering Sea (BS) variability. Sensitivity experiments, each one with a different strength of the AS transport reveal a nonlinear BS response. An increase of AS transport from 10 to 25 Sv causes warming (similar to 0.25 degrees C mean, similar to 0.5 degrees C maximum) and sea level rise in the BS shelf due to increased transports of warmer Pacific waters through the eastern passages of the Aleutian …


On The Nature Of Winter Cooling And The Recent Temperature Shift On The Northern Gulf Of Alaska Shelf, Markus A. Janout, Thomas J. Weingartner, Thomas C. Royer, Seth L. Danielson Jan 2010

On The Nature Of Winter Cooling And The Recent Temperature Shift On The Northern Gulf Of Alaska Shelf, Markus A. Janout, Thomas J. Weingartner, Thomas C. Royer, Seth L. Danielson

CCPO Publications

[1] In spring 2006 and 2007, northern Gulf of Alaska (GOA) shelf waters were ∼1.5°C below average throughout the similar to ∼250 m deep shelf and the salinity-dependent winter stratification was anomalously weak due to above (below) average surface (bottom) salinities. Spring 2007 and 2008 temperatures were also similar to ∼-1.5°C below average, but the anomalies were confined to the upper 100 m due to moderate salt stratification. Shelf temperatures in these 2 years were among the lowest observed since the early 1970s, thus interrupting an approximately 30-year warming trend. We examined winter cooling processes using historical conductivity-temperature-depth (CTD) profiles …


Causes Of Tropical Atlantic Paleo-Salinity Variation During Periods Of Reduced Amoc, Xiuquan Wan, Ping Chang, Matthew W. Schmidt Jan 2010

Causes Of Tropical Atlantic Paleo-Salinity Variation During Periods Of Reduced Amoc, Xiuquan Wan, Ping Chang, Matthew W. Schmidt

OES Faculty Publications

During periods of reduced Atlantic meridional overturning circulation (AMOC) associated with a freshening of northern North Atlantic surface water, paleo proxy records indicate a corresponding surface salinity increase over the entire tropical Atlantic. Although latitudinal-shifts in the mean position of the Atlantic Intertropical Convergence Zone (ITCZ) can explain certain features of the paleo salinity reconstructions, this mechanism does not offer an explanation for the reconstructed basin-wide paleo-salinity response to AMOC change. Here, we present new results from general circulation model simulations that suggest the sea surface salinity (SSS) increase in the tropical north Atlantic during periods of weakened AMOC is …


On The Interpretation Of Caribbean Paleo-Temperature Reconstructions During The Younger Dryas, Xiuquan Wan, Ping Chang, R. Saravanan, Rong Zhang, Matthew W. Schmidt Jan 2009

On The Interpretation Of Caribbean Paleo-Temperature Reconstructions During The Younger Dryas, Xiuquan Wan, Ping Chang, R. Saravanan, Rong Zhang, Matthew W. Schmidt

OES Faculty Publications

A conundrum exists regarding whether the sea-surface temperatures decreased or increased over the southern Caribbean and the western Tropical Atlantic region during the Younger Dryas when the North Atlantic cooled substantially and the Atlantic thermohaline circulation was weakened significantly. Despite the proximity of core locations, some proxy reconstructions record a surface cooling, while others indicate a warming. We suggest that this seemingly paradoxical finding may, at least partially, be attributed to the competing physical processes that result in opposing signs of temperature change in the region in response to weakened North Atlantic meridional overturning circulation. Our coupled ocean-atmosphere model experiments …


Ocean Warming And Freshening In The Northern Gulf Of Alaska, Thomas C. Royer, Chester E. Grosch Jan 2006

Ocean Warming And Freshening In The Northern Gulf Of Alaska, Thomas C. Royer, Chester E. Grosch

CCPO Publications

Water column temperatures on the shelf in the northern Gulf of Alaska have increased more than 0.8 degrees C and vertical density stratification has increased since 1970 near Seward, Alaska throughout the 250 m depth. This high latitude marine system has low water temperatures, high rates of precipitation, glacial melting, high wind speeds and high rates of biological productivity. A more than 300 km alongshore shift ( locally westward) of isotherms is suggested. The observations are consistent with a conceptual ocean-atmosphere circulation model that employs coastal freshwater discharge, glacial ablation and wind forcing. Positive regional feedback mechanisms accelerate the discharge …


Inter-Annual Sea Level Variability In The Southern Gulf Of Mexico (1966-1976), David Alberto Salas-De-León, Maria Adela Monreal-Gómez, David Salas-Monreal, Mayra Lorena Riveron-Enzastiga, Norma Leticia Sánchez-Santillan Jan 2006

Inter-Annual Sea Level Variability In The Southern Gulf Of Mexico (1966-1976), David Alberto Salas-De-León, Maria Adela Monreal-Gómez, David Salas-Monreal, Mayra Lorena Riveron-Enzastiga, Norma Leticia Sánchez-Santillan

CCPO Publications

Hourly time series at seven locations throughout the southern Gulf of Mexico were used to calculate the trend and the inter-annual sea level. The sea level series from January 1966 to December 1976 were filtered using a Lanczos low pass filter to remove oscillations with periods smaller than one year. The results revealed a sea level increment of about 1.4 mm yr(-1) from 1966 to 1976 in the southern Gulf of Mexico. The monthly sea level variability obtained after the trends were removed, presented a sea level setup during winter and a sea level depression in summer attributed to seasonal …


Variability Of Sea Ice Cover In The Chukchi Sea (Western Arctic Ocean) During The Holocene, Anne De Vernal, Claude Hillaire-Marcel, Dennis A. Darby Jan 2005

Variability Of Sea Ice Cover In The Chukchi Sea (Western Arctic Ocean) During The Holocene, Anne De Vernal, Claude Hillaire-Marcel, Dennis A. Darby

OES Faculty Publications

Dinocysts from cores collected in the Chukchi Sea from the shelf edge to the lower slope were used to reconstruct changes in sea surface conditions and sea ice cover using modern analogue techniques. Holocene sequences have been recovered in a down-slope core (B15: 2135 m, 75°44'N, sedimentation rate of ~1cm kyr-1) and in a shelf core (P1: 201 m, 73°41'N, sedimentation rate of ~22 cm kyr-1). The shelf record spanning about 8000 years suggests high-frequency centennial oscillations of sea surface conditions and a significant reduction of the sea ice at circa 6000 and 2500 calendar (cal) …


Hydrographic And Biological Changes In The Taiwan Strait During The 1997-1998 El Niño Winter, S. Shang, C. Zhang, H. Hong, Q. Liu, G. T. F. Wong, C. Hu, B. Huang Jan 2005

Hydrographic And Biological Changes In The Taiwan Strait During The 1997-1998 El Niño Winter, S. Shang, C. Zhang, H. Hong, Q. Liu, G. T. F. Wong, C. Hu, B. Huang

OES Faculty Publications

During the 1997–1998 El Niño event, the average sea surface temperature (SST) in the Taiwan Strait (TWS) in the winter was ~1.4°C higher than that of the winter climatological mean. The areal ratio of the warm water (≥2°C above the regional mean) to the cold water (≥2°C below the regional mean) in the TWS increased by 25% while the area of the eutrophic water (chlorophyll a >1 mg m-3) was halved. Field observations also indicate that the mixed layer in the TWS became more nutrient-poor during this winter. These observations are consistent with a diminished advection of the …


Flow Induced By Upwelling Winds In An Equatorward Facing Bay: Gulf Of Arauco, Chile, Arnoldo Valle-Levinson, Larry P. Atkinson, Dante Figueroa, Leonardo Castro Jan 2003

Flow Induced By Upwelling Winds In An Equatorward Facing Bay: Gulf Of Arauco, Chile, Arnoldo Valle-Levinson, Larry P. Atkinson, Dante Figueroa, Leonardo Castro

CCPO Publications

[1] Shipborne observations of hydrographic and flow velocity profiles were combined with wind velocity measurements to describe the characteristics of the wind-induced flow in an equatorward facing bay of central Chile in South America. The measurements, which were taken from two transects and one anchor station, were made during late austral spring, between 4 and 10 December 2000. Most observations concentrated on Boca Grande, a transect that crossed the deep, northern ( equatorward) entrance to the bay. The other transect crossed the smaller and shallower, westward entrance to the bay, Boca Chica. The anchor station was located inside the bay, …


Reconstructing Basin-Scale Eulerian Velocity Fields From Simulated Drifter Data, M. Toner, A. C. Poje, A. D. Kirwan, C. K. R. T. Jones, B. L. Lipphardt, C. E. Grosch Jan 2001

Reconstructing Basin-Scale Eulerian Velocity Fields From Simulated Drifter Data, M. Toner, A. C. Poje, A. D. Kirwan, C. K. R. T. Jones, B. L. Lipphardt, C. E. Grosch

CCPO Publications

A single-layer, reduced-gravity, double-gyre primitive equation model in a 2000 km x 2000 km square domain is used to test the accuracy and sensitivity of time-dependent Eulerian velocity fields reconstructed from numerically generated drifter trajectories and climatology. The goal is to determine how much Lagrangian data is needed to capture the Eulerian velocity field within a specified accuracy. The Eulerian fields are found by projecting, on an analytic set of divergence-free basis functions, drifter data launched in the active western half of the basin supplemented by climatology in the eastern domain. The time-dependent coefficients are evaluated by least squares minimization …