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Author
Ansong, J.K. ; Arbic, B.K. ; Simmons, H.L. ; Alford, M.H. ; Buijsman, M.C. ; Timko, P.G. ; Richman, J.G. ; Shriver, J.F. ; Wallcraft, A.J.
Title
Geographical Distribution of Diurnal and Semidiurnal Parametric Subharmonic Instability in a Global Ocean Circulation Model
Type
$loc['typeJournal Article']
Year
2018
Publication
Journal of Physical Oceanography
Abbreviated Journal
J. Phys. Oceanogr.
Volume
48
Issue
6
Pages
1409-1431
Keywords
Baroclinic flows ; Internal waves ; Nonlinear dynamics ; Ocean dynamics ; Baroclinic models ; Ocean models
Abstract
The evidence for, baroclinic energetics of, and geographic distribution of parametric subharmonic instability (PSI) arising from both diurnal and semidiurnal tides in a global ocean general circulation model is investigated using 1/12.5° and 1/25° simulations that are forced by both atmospheric analysis fields and the astronomical tidal potential. The paper examines whether PSI occurs in the model, and whether it accounts for a significant fraction of the tidal baroclinic energy loss. Using energy transfer calculations and bispectral analyses, evidence is found for PSI around the critical latitudes of the tides. The intensity of both diurnal and semidiurnal PSI in the simulations is greatest in the upper ocean, consistent with previous results from idealized simulations, and quickly drops off about 5° from the critical latitudes. The sign of energy transfer depends on location; the transfer is positive (from the tides to subharmonic waves) in some locations and negative in others. The net globally integrated energy transfer is positive in all simulations and is 0.5%�10% of the amount of energy required to close the baroclinic energy budget in the model. The net amount of energy transfer is about an order of magnitude larger in the 1/25° semidiurnal simulation than the 1/12.5° one, implying the dependence of the rate of energy transfer on model resolution.
Address
Corporate Author
Thesis
Publisher
Place of Publication
Editor
Language
Summary Language
Original Title
Series Editor
Series Title
Abbreviated Series Title
Series Volume
Series Issue
Edition
ISSN
0022-3670
ISBN
Medium
Area
Expedition
Conference
Funding
Approved
$loc['no']
Call Number
COAPS @ user @
Serial
976
Permanent link to this record
Author
Xu, X. ; Rhines, P.B. ; Chassignet, E.P.
Title
On Mapping the Diapycnal Water Mass Transformation of the Upper North Atlantic Ocean
Type
$loc['typeJournal Article']
Year
2018
Publication
Journal of Physical Oceanography
Abbreviated Journal
J. Phys. Oceanogr.
Volume
48
Issue
10
Pages
2233-2258
Keywords
Atmosphere-ocean interaction ; Boundary currents ; Diapycnal mixing ; Fronts ; Thermocline circulation
Abstract
Diapycnal water mass transformation is the essence behind the Atlantic meridional overturning circulation (AMOC) and the associated heat/freshwater transports. Existing studies have mostly focused on the transformation that is forced by surface buoyancy fluxes, and the role of interior mixing is much less known. This study maps the three-dimensional structure of the diapycnal transformation, both surface forced and mixing induced, using results of a high-resolution numerical model that have been shown to represent the large-scale structure of the AMOC and the North Atlantic subpolar/subtropical gyres well. The analyses show that 1) annual mean transformation takes place seamlessly from the subtropical to the subpolar North Atlantic following the surface buoyancy loss along the northward-flowing upper AMOC limb; 2) mixing, including wintertime convection and warm-season restratification by mesoscale eddies in the mixed layer and submixed layer diapycnal mixing, drives transformations of (i) Subtropical Mode Water in the southern part of the subtropical gyre and (ii) Labrador Sea Water in the Labrador Sea and on its southward path in the western Newfoundland Basin; and 3) patterns of diapycnal transformations toward lighter and denser water do not align zonally�the net three-dimensional transformation is significantly stronger than the zonally integrated, two-dimensional AMOC streamfunction (50% in the southern subtropical North Atlantic and 60% in the western subpolar North Atlantic).
Address
Corporate Author
Thesis
Publisher
Place of Publication
Editor
Language
Summary Language
Original Title
Series Editor
Series Title
Abbreviated Series Title
Series Volume
Series Issue
Edition
ISSN
0022-3670
ISBN
Medium
Area
Expedition
Conference
Funding
Approved
$loc['no']
Call Number
COAPS @ user @
Serial
951
Permanent link to this record
Author
Steffen, J. ; Bourassa, M.
Title
Barrier Layer Development Local to Tropical Cyclones based on Argo Float Observations
Type
$loc['typeJournal Article']
Year
2018
Publication
Journal of Physical Oceanography
Abbreviated Journal
J. Phys. Oceanogr.
Volume
48
Issue
9
Pages
1951-1968
Keywords
SEA-SURFACE TEMPERATURE ; UPPER-OCEAN RESPONSE ; NINO SOUTHERN-OSCILLATION ; MIXED-LAYER ; INDIAN-OCEAN ; HEAT-BUDGET ; NUMERICAL SIMULATIONS ; HURRICANES ; VARIABILITY ; PACIFIC
Abstract
The objective of this study is to quantify barrier layer development due to tropical cyclone (TC) passage using Argo float observations of temperature and salinity. To accomplish this objective, a climatology of Argo float measurements is developed from 2001 to 2014 for the Atlantic, eastern Pacific, and central Pacific basins. Each Argo float sample consists of a prestorm and poststorm temperature and salinity profile pair. In addition, a no-TC Argo pair dataset is derived for comparison to account for natural ocean state variability and instrument sensitivity. The Atlantic basin shows a statistically significant increase in barrier layer thickness (BLT) and barrier layer potential energy (BLPE) that is largely attributable to an increase of 2.6 m in the post-TC isothermal layer depth (ITLD). The eastern Pacific basin shows no significant changes to any barrier layer characteristic, likely due to a shallow and highly stratified pycnocline. However, the near-surface layer freshens in the upper 30 m after TC passage, which increases static stability. Finally, the central Pacific has a statistically significant freshening in the upper 20-30 m that increases upper-ocean stratification by similar to 35%. The mechanisms responsible for increases in BLPE vary between the Atlantic and both Pacific basins; the Atlantic is sensitive to ITLD deepening, while the Pacific basins show near-surface freshening to be more important in barrier layer development. In addition, Argo data subsets are used to investigate the physical relationships between the barrier layer and TC intensity, TC translation speed, radial distance from TC center, and time after TC passage.
Address
Corporate Author
Thesis
Publisher
Place of Publication
Editor
Language
Summary Language
Original Title
Series Editor
Series Title
Abbreviated Series Title
Series Volume
Series Issue
Edition
ISSN
0022-3670
ISBN
Medium
Area
Expedition
Conference
Funding
Approved
$loc['no']
Call Number
COAPS @ user @
Serial
970
Permanent link to this record
Author
Holbach, H.M. ; Uhlhorn, E.W. ; Bourassa, M.A.
Title
Off-Nadir SFMR Brightness Temperature Measurements in High-Wind Conditions
Type
$loc['typeJournal Article']
Year
2018
Publication
Journal of Atmospheric and Oceanic Technology
Abbreviated Journal
J. Atmos. Oceanic Technol.
Volume
35
Issue
9
Pages
1865-1879
Keywords
Tropical cyclones ; Wind ; Air-sea interaction ; Microwave observations ; Remote sensing ; Surface observations
Abstract
Wind and wave-breaking directions are investigated as potential sources of an asymmetry identified in off-nadir remotely sensed measurements of ocean surface brightness temperatures obtained by the Stepped Frequency Microwave Radiometer (SFMR) in high-wind conditions, including in tropical cyclones. Surface wind speed, which dynamically couples the atmosphere and ocean, can be inferred from SFMR ocean surface brightness temperature measurements using a radiative transfer model and an inversion algorithm. The accuracy of the ocean surface brightness temperature to wind speed calibration relies on accurate knowledge of the surface variables that are influencing the ocean surface brightness temperature. Previous studies have identified wind direction signals in horizontally polarized radiometer measurements in low to moderate (0�20 m s−1) wind conditions over a wide range of incidence angles. This study finds that the azimuthal asymmetry in the off-nadir SFMR brightness temperature measurements is also likely a function of wind direction and extends the results of these previous studies to high-wind conditions. The off-nadir measurements from the SFMR provide critical data for improving the understanding of the relationships between brightness temperature, surface wave�breaking direction, and surface wind vectors at various incidence angles, which is extremely useful for the development of geophysical model functions for instruments like the Hurricane Imaging Radiometer (HIRAD).
Address
Corporate Author
Thesis
Publisher
Place of Publication
Editor
Language
Summary Language
Original Title
Series Editor
Series Title
Abbreviated Series Title
Series Volume
Series Issue
Edition
ISSN
0739-0572
ISBN
Medium
Area
Expedition
Conference
Funding
Approved
$loc['no']
Call Number
COAPS @ rl18 @
Serial
980
Permanent link to this record
Author
Devanas, A. ; Stefanova, L.
Title
Statistical Prediction Of Waterspout Probability For The Florida Keys
Type
$loc['typeJournal Article']
Year
2018
Publication
Weather and Forecasting
Abbreviated Journal
Wea. Forecasting
Volume
33
Issue
Pages
389-410
Keywords
Regression analysis ; Forecast verification/skill ; Forecasting techniques ; Probability forecasts/models/distribution ; Statistical forecasting
Abstract
A statistical model of waterspout probability was developed for wet-season (June–September) days over the Florida Keys. An analysis was performed on over 200 separate variables derived from Key West 1200 UTC daily wet-season soundings during the period 2006–14. These variables were separated into two subsets: days on which a waterspout was reported anywhere in the Florida Keys coastal waters and days on which no waterspouts were reported. Days on which waterspouts were reported were determined from the National Weather Service (NWS) Key West local storm reports. The sounding at Key West was used for this analysis since it was assumed to be representative of the atmospheric environment over the area evaluated in this study. The probability of a waterspout report day was modeled using multiple logistic regression with selected predictors obtained from the sounding variables. The final model containing eight separate variables was validated using repeated fivefold cross validation, and its performance was compared to that of an existing waterspout index used as a benchmark. The performance of the model was further validated in forecast mode using an independent verification wet-season dataset from 2015–16 that was not used to define or train the model. The eight-predictor model was found to produce a probability forecast with robust skill relative to climatology and superior to the benchmark waterspout index in both the cross validation and in the independent verification.
Address
Corporate Author
Thesis
Publisher
Place of Publication
Editor
Language
Summary Language
Original Title
Series Editor
Series Title
Abbreviated Series Title
Series Volume
Series Issue
Edition
ISSN
0882-8156
ISBN
Medium
Area
Expedition
Conference
Funding
Approved
$loc['no']
Call Number
COAPS @ mfield @
Serial
553
Permanent link to this record
Author
Hu, X. ; Cai, M. ; Yang, S. ; Wu, Z.
Title
Delineation of thermodynamic and dynamic responses to sea surface temperature forcing associated with El Niño
Type
$loc['typeJournal Article']
Year
2018
Publication
Climate Dynamics
Abbreviated Journal
Clim Dyn
Volume
51
Issue
11-12
Pages
4329-4344
Keywords
El Niño ; SST anomalies ; Thermodynamic and dynamic responses ; Gill-type response
Abstract
A new framework is proposed to gain a better understanding of the response of the atmosphere over the tropical Pacific to the radiative heating anomaly associated with the sea surface temperature (SST) anomaly in canonical El Niño winters. The new framework is based on the equilibrium balance between thermal radiative cooling anomalies associated with air temperature response to SST anomalies and other thermodynamic and dynamic processes. The air temperature anomalies in the lower troposphere are mainly in response to radiative heating anomalies associated with SST, atmospheric water vapor, and cloud anomalies that all exhibit similar spatial patterns. As a result, air temperature induced thermal radiative cooling anomalies would balance out most of the radiative heating anomalies in the lower troposphere. The remaining part of the radiative heating anomalies is then taken away by an enhancement (a reduction) of upward energy transport in the central-eastern (western) Pacific basin, a secondary contribution to the air temperature anomalies in the lower troposphere. Above the middle troposphere, radiative effect due to water vapor feedback is weak. Thermal radiative cooling anomalies are mainly in balance with the sum of latent heating anomalies, vertical and horizontal energy transport anomalies associated with atmospheric dynamic response and the radiative heating anomalies due to changes in cloud. The pattern of Gill-type response is attributed mainly to the non-radiative heating anomalies associated with convective and large-scale energy transport. The radiative heating anomalies associated with the anomalies of high clouds also contribute positively to the Gill-type response. This sheds some light on why the Gill-type atmospheric response can be easily identifiable in the upper atmosphere.
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Thesis
Publisher
Place of Publication
Editor
Language
Summary Language
Original Title
Series Editor
Series Title
Abbreviated Series Title
Series Volume
Series Issue
Edition
ISSN
0930-7575
ISBN
Medium
Area
Expedition
Conference
Funding
Approved
$loc['no']
Call Number
COAPS @ user @
Serial
997
Permanent link to this record
Author
van Sebille, E. ; Griffies, S.M. ; Abernathey, R. ; Adams, T.P. ; Berloff, P. ; Biastoch, A. ; Blanke, B. ; Chassignet, E.P. ; Cheng, Y. ; Cotter, C.J. ; Deleersnijder, E. ; Döös, K. ; Drake, H.F. ; Drijfhout, S. ; Gary, S.F. ; Heemink, A.W. ; Kjellsson, J. ; Koszalka, I.M. ; Lange, M. ; Lique, C. ; MacGilchrist, G.A. ; Marsh, R. ; Mayorga Adame, C.G. ; McAdam, R. ; Nencioli, F. ; Paris, C.B. ; Piggott, M.D. ; Polton, J.A. ; Rühs, S. ; Shah, S.H.A.M. ; Thomas, M.D. ; Wang, J. ; Wolfram, P.J. ; Zanna, L. ; Zika, J.D.
Title
Lagrangian ocean analysis: Fundamentals and practices
Type
$loc['typeJournal Article']
Year
2018
Publication
Ocean Modelling
Abbreviated Journal
Ocean Modelling
Volume
121
Issue
Pages
49-75
Keywords
Ocean circulation ; Lagrangian analysis ; Connectivity ; Particle tracking ; Future modelling
Abstract
Address
Corporate Author
Thesis
Publisher
Place of Publication
Editor
Language
Summary Language
Original Title
Series Editor
Series Title
Abbreviated Series Title
Series Volume
Series Issue
Edition
ISSN
1463-5003
ISBN
Medium
Area
Expedition
Conference
Funding
Approved
$loc['no']
Call Number
COAPS @ mfield @
Serial
466
Permanent link to this record
Author
Stukel, M. R. ; Song, H. ; Goericke, R. ; Miller, A.J.
Title
The role of subduction and gravitational sinking in particle export, carbon sequestration, and the remineralization length scale in the California Current Ecosystem
Type
$loc['typeJournal Article']
Year
2018
Publication
Limnology and Oceanography
Abbreviated Journal
Volume
63
Issue
1
Pages
363-383
Keywords
Abstract
Address
Corporate Author
Thesis
Publisher
Place of Publication
Editor
Language
Summary Language
Original Title
Series Editor
Series Title
Abbreviated Series Title
Series Volume
Series Issue
Edition
ISSN
ISBN
Medium
Area
Expedition
Conference
Funding
Approved
$loc['no']
Call Number
COAPS @ mfield @
Serial
362
Permanent link to this record
Author
Stauffer, C. L.
Title
Air-sea coupling dependency on sea surface temperature fronts as observed by research vessel data
Type
$loc['typeManuscript']
Year
2018
Publication
Abbreviated Journal
Volume
Issue
Pages
Keywords
Abstract
Address
Department of Earth Ocean and Atmospheric Science
Corporate Author
Thesis
$loc['Bachelor's thesis']
Publisher
Florida State University
Place of Publication
Tallahassee, FL
Editor
Language
Summary Language
Original Title
Series Editor
Series Title
Abbreviated Series Title
Series Volume
Series Issue
Edition
ISSN
ISBN
Medium
Area
Expedition
Conference
Funding
Approved
$loc['no']
Call Number
COAPS @ mfield @
Serial
945
Permanent link to this record
Author
Morey, S. ; Wienders, N. ; Dukhovskoy, D. ; Bourassa, M.
Title
Measurement Characteristics of Near-Surface Currents from Ultra-Thin Drifters, Drogued Drifters, and HF Radar
Type
$loc['typeJournal Article']
Year
2018
Publication
Remote Sensing
Abbreviated Journal
Remote Sensing
Volume
10
Issue
10
Pages
1633
Keywords
surface drifters ; surface currents ; HF Radar
Abstract
Concurrent measurements by satellite tracked drifters of different hull and drogue configurations and coastal high-frequency radar reveal substantial differences in estimates of the near-surface velocity. These measurements are important for understanding and predicting material transport on the ocean surface as well as the vertical structure of the near-surface currents. These near-surface current observations were obtained during a field experiment in the northern Gulf of Mexico intended to test a new ultra-thin drifter design. During the experiment, thirty small cylindrical drifters with 5 cm height, twenty-eight similar drifters with 10 cm hull height, and fourteen drifters with 91 cm tall drogues centered at 100 cm depth were deployed within the footprint of coastal High-Frequency (HF) radar. Comparison of collocated velocity measurements reveals systematic differences in surface velocity estimates obtained from the different measurement techniques, as well as provides information on properties of the drifter behavior and near-surface shear. Results show that the HF radar velocity estimates had magnitudes significantly lower than the 5 cm and 10 cm drifter velocity of approximately 45% and 35%, respectively. The HF radar velocity magnitudes were similar to the drogued drifter velocity. Analysis of wave directional spectra measurements reveals that surface Stokes drift accounts for much of the velocity difference between the drogued drifters and the thin surface drifters except during times of wave breaking.
Address
Corporate Author
Thesis
Publisher
Place of Publication
Editor
Language
Summary Language
Original Title
Series Editor
Series Title
Abbreviated Series Title
Series Volume
Series Issue
Edition
ISSN
2072-4292
ISBN
Medium
Area
Expedition
Conference
Funding
Approved
$loc['no']
Call Number
COAPS @ rl18 @
Serial
987
Permanent link to this record