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Author
Rahaman, H. ; Srinivasu, U. ; Panickal, S. ; Durgadoo, J.V. ; Griffies, S.M. ; Ravichandran, M. ; Bozec, A. ; Cherchi, A. ; Voldoire, A. ; Sidorenko, D.. ; Chassignet, E.P. ; Danabasoglu, G. ; Tsujino, H. ; Getzlaff, K. ; Ilicak, M. ; Bentsen, M. ; Long, M.C. ; Fogli, P.G. ; Farneti, R. ; Danilov, S. ; Marsland, S.J. ; Valcke, S. ; Yeager, S.G. ; Wang, Q.
Title
An assessment of the Indian Ocean mean state and seasonal cycle in a suite of interannual CORE-II simulations
Type
$loc['typeJournal Article']
Year
2020
Publication
Ocean Modelling
Abbreviated Journal
Ocean Modelling
Volume
145
Issue
Pages
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
1463-5003
ISBN
Medium
Area
Expedition
Conference
Funding
Approved
$loc['no']
Call Number
COAPS @ user @
Serial
1087
Permanent link to this record
Author
Timko, P.G. ; Arbic, B.K. ; Hyder, P. ; Richman, J.G. ; Zamudio, L. ; O'Dea, E. ; Wallcraft, A.J. ; Shriver, J.F.
Title
Assessment of shelf sea tides and tidal mixing fronts in a global ocean model
Type
$loc['typeJournal Article']
Year
2019
Publication
Ocean Modelling
Abbreviated Journal
Ocean Modelling
Volume
136
Issue
Pages
66-84
Keywords
HYCOM ; tides ; seasonal tidal mixing
Abstract
Tidal mixing fronts, which represent boundaries between stratified and tidally mixed waters, are locations of enhanced biological activity. They occur in summer shelf seas when, in the presence of strong tidal currents, mixing due to bottom friction balances buoyancy production due to seasonal heat flux. In this paper we examine the occurrence and fidelity of tidal mixing fronts in shelf seas generated within a global 3-dimensional simulation of the HYbrid Coordinate Ocean Model (HYCOM) that is simultaneously forced by atmospheric fields and the astronomical tidal potential. We perform a first order assessment of shelf sea tides in global HYCOM through comparison of sea surface temperature, sea surface tidal elevations, and tidal currents with observations. HYCOM was tuned to minimize errors in M2 sea surface heights in deep water. Over the global coastal and shelf seas (depths <200 m) the area-weighted root mean square error of the M2 sea surface amplitude in HYCOM represents 35% of the 50 cm root mean squared M2 sea surface amplitude when compared to satellite constrained models TPXO8 and FES2014. HYCOM and the altimeter constrained tidal models TPXO8 and FES2014 exhibit similar skill in reproducing barotropic tidal currents estimated from in-situ current meter observations. Through comparison of a global HYCOM simulation with tidal forcing to a global HYCOM simulation with no tides, and also to previous regional studies of tidal mixing fronts in shelf seas, we demonstrate that HYCOM with embedded tides exhibits quite high skill in reproducing known tidal mixing fronts in shelf seas. Our results indicate that the amount of variability in the location of the tidal mixing fronts in HYCOM, estimated using the Simpson-Hunter parameter, is consistent with previous studies when the differences in the net downward heat flux, on a global scale, are taken into account. We also provide evidence of tidal mixing fronts on the North West Australian Shelf for which we have been unable to find references in the existing scientific literature.
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 @ user @
Serial
1032
Permanent link to this record
Author
Jeon, C.-H. ; Buijsman, M.C. ; Wallcraft, A.J. ; Shriver, J.F. ; Arbic, B.K. ; Richman, J.G. ; Hogan, P.J.
Title
Improving surface tidal accuracy through two-way nesting in a global ocean model
Type
$loc['typeJournal Article']
Year
2019
Publication
Ocean Modelling
Abbreviated Journal
Ocean Modelling
Volume
137
Issue
Pages
98-113
Keywords
Two-way nesting ; HYCOM ; Barotropic tides ; OASIS3-MCT ; FES2014 ; TPXO9-atlas
Abstract
In global ocean simulations, forward (non-data-assimilative) tide models generally feature large sea-surface-height errors near Hudson Strait in the North Atlantic Ocean with respect to altimetry-constrained tidal solutions. These errors may be associated with tidal resonances that are not well resolved by the complex coastal-shelf bathymetry in low-resolution simulations. An online two-way nesting framework has been implemented to improve global surface tides in the HYbrid Coordinate Ocean Model (HYCOM). In this framework, a high-resolution child domain, covering Hudson Strait, is coupled with a relatively low-resolution parent domain for computational efficiency. Data such as barotropic pressure and velocity are exchanged between the child and parent domains with the external coupler OASIS3-MCT. The developed nesting framework is validated with semi-idealized basin-scale model simulations. The M2 sea-surface heights show very good accuracy in the one-way and two-way nesting simulations in Hudson Strait, where large tidal elevations are observed. In addition, the mass and tidal energy flux are not adversely impacted at the nesting boundaries in the semi-idealized simulations. In a next step, the nesting framework is applied to a realistic global tide simulation. In this simulation, the resolution of the child domain (1/75°) is three times as fine as that of the parent domain (1/25°). The M2 sea-surface-height root-mean-square errors with tide gauge data and the altimetry-constrained global FES2014 and TPXO9-atlas tidal solutions are evaluated for the nesting and no-nesting solutions. The better resolved coastal bathymetry and the finer grid in the child domain improve the local tides in Hudson Strait and Bay, and the back-effect of the coastal tides induces an improvement of the barotropic tides in the open ocean of the 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
1463-5003
ISBN
Medium
Area
Expedition
Conference
Funding
Approved
$loc['no']
Call Number
COAPS @ user @
Serial
1034
Permanent link to this record
Author
Jeon, C.-H. ; Buijsman, M.C. ; Wallcraft, A.J. ; Shriver, J.F. ; Arbic, B.K. ; Richman, J.G. ; Hogan, P.J.
Title
Improving surface tidal accuracy through two-way nesting in a global ocean model
Type
$loc['typeJournal Article']
Year
Publication
Ocean Modelling
Abbreviated Journal
Ocean Modelling
Volume
Issue
Pages
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
1463-5003
ISBN
Medium
Area
Expedition
Conference
Funding
Approved
$loc['no']
Call Number
COAPS @ user @
Serial
1035
Permanent link to this record
Author
Kelly, T.B. ; Goericke, R. ; Kahru, M. ; Song, H. ; Stukel, M.R.
Title
CCE II: Spatial and interannual variability in export efficiency and the biological pump in an eastern boundary current upwelling system with substantial lateral advection
Type
$loc['typeJournal Article']
Year
2018
Publication
Deep Sea Research Part I: Oceanographic Research Papers
Abbreviated Journal
Deep Sea Research Part I: Oceanographic Research Papers
Volume
140
Issue
Pages
14-25
Keywords
CALIFORNIA CURRENT ECOSYSTEM ; OCEAN CARBON-CYCLE ; COASTAL WATERS ; FRONTAL ZONE ; TIME-SERIES ; FLUX ; SINKING ; SEA ; PACIFIC ; ZOOPLANKTON
Abstract
Estimating interannual variability in carbon export is a key goal of many marine biogeochemical studies. However, due to variations in export mechanisms between regions, generalized models used to estimate global patterns in export often fail when used for intra-regional analysis. We present here a region-specific model of export production for the California Current Ecosystem (CCE) parameterized using intensive Lagrangian process studies conducted during El Niño-Southern Oscillation (ENSO) warm and neutral phases by the CCE Long-Term Ecological Research (LTER) program. We find that, contrary to expectations from prominent global algorithms, export efficiency (e-ratio = export / primary productivity) is positively correlated with temperature and negatively correlated with net primary productivity (NPP). We attribute these results to the substantial horizontal advection found within the region, and verify this assumption by using a Lagrangian particle tracking model to estimate water mass age. We further suggest that sinking particles in the CCE are comprised of a recently-produced, rapidly-sinking component (likely mesozooplankton fecal pellets) and a longer-lived, slowly-sinking component that is likely advected long distances prior to export. We determine a new algorithm for estimating particle export in the CCE from NPP (Export = 0.08 · NPP + 72 mg C m-2 d-1). We apply this algorithm to a two-decade long time series of NPP in the CCE to estimate spatial and interannual variability across multiple ENSO phases. Reduced export during the warm anomaly of 2014-2015 and El Niño 2015-2016 resulted primarily from decreased export in the coastal upwelling region of the CCE; the oligotrophic offshore region exhibited comparatively low seasonal and interannual variability in flux. The model resolves intra-regional patterns of in situ export measurements, and provides a valuable contrast to global export models.
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
0967-0637
ISBN
Medium
Area
Expedition
Conference
Funding
Approved
$loc['no']
Call Number
COAPS @ rl18 @
Serial
984
Permanent link to this record
Author
Kelly, T.B. ; Goericke, R. ; Kahru, M. ; Song, H. ; Stukel, M.R.
Title
CCE II: Spatial and interannual variability in export efficiency and the biological pump in an eastern boundary current upwelling system with substantial lateral advection
Type
$loc['typeJournal Article']
Year
2018
Publication
Deep Sea Research Part I: Oceanographic Research Papers
Abbreviated Journal
Deep Sea Research Part I: Oceanographic Research Papers
Volume
140
Issue
Pages
14-25
Keywords
california current ecosystem ; coastal waters ; flux ; frontal zone ; ocean carbon-cycle ; oceanography ; pacific ; sea ; sinking ; time-series ; Zooplankton
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
0967-0637
ISBN
Medium
Area
Expedition
Conference
Funding
Approved
$loc['no']
Call Number
COAPS @ user @
Serial
1022
Permanent link to this record
Author
Morrow, R.M. ; Ohman, M.D. ; Goericke, R. ; Kelly, T.B. ; Stephens, B.M. ; Stukel, M.R.
Title
CCE V: Primary production, mesozooplankton grazing, and the biological pump in the California Current Ecosystem: Variability and response to El Niño
Type
$loc['typeJournal Article']
Year
2018
Publication
Deep Sea Research Part I: Oceanographic Research Papers
Abbreviated Journal
Deep Sea Research Part I: Oceanographic Research Papers
Volume
140
Issue
Pages
52-62
Keywords
Carbon export ; Fecal pellets ; Sinking particles ; Interannual variability ; Net primary productivity ; Eastern boundary upwelling system KeyWords Plus:ZOOPLANKTON FECAL PELLETS ; NORTH PACIFIC-OCEAN ; CURRENT SYSTEM ; SOUTHERN CALIFORNIA ; UNDERWATER GLIDERS ; CARBON EXPORT ; ZONE ; CHLOROPHYLL ; STABILITY ; EQUATIONS
Abstract
Predicting marine carbon sequestration in a changing climate requires mechanistic understanding of the processes controlling sinking particle flux under different climatic conditions. The recent occurrence of a warm anomaly (2014-2015) followed by an El Nino (2015-2016) in the southern sector of the California Current System presented an opportunity to analyze changes in the biological carbon pump in response to altered climate forcing. We compare primary production, mesozooplankton grazing, and carbon export from the euphotic zone during quasi-Lagrangian experiments conducted in contrasting conditions: two cruises during warm years – one during the warm anomaly in 2014 and one toward the end of El Nino 2016 – and three cruises during El Ninoneutral years. Results showed no substantial differences in the relationships between vertical carbon export and its presumed drivers (primary production, mesozooplankton grazing) between warm and neutral years. Mesozooplankton fecal pellet enumeration and phaeopigment measurements both showed that fecal pellets were the dominant contributor to export in productive upwelling regions. In more oligotrophic regions, fluxes were dominated by amorphous marine snow with negligible pigment content. We found no evidence for a significant shift in the relationship between mesozooplankton grazing rate and chlorophyll concentration. However, massspecific grazing rates were lower at low-to-moderate chlorophyll concentrations during warm years relative to neutral years. We also detected a significant difference in the relationship between phytoplankton primary production and photosynthetically active radiation between years: at similar irradiance and nutrient concentrations, productivity decreased during the warm events. Whether these changes resulted from species composition changes remains to be determined. Overall, our results suggest that the processes driving export remain similar during different climate conditions, but that species compositional changes or other structural changes require further attention.
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
0967-0637
ISBN
Medium
Area
Expedition
Conference
Funding
Approved
$loc['no']
Call Number
COAPS @ rl18 @
Serial
983
Permanent link to this record
Author
Morrow, R.M. ; Ohman, M.D. ; Goericke, R. ; Kelly, T.B. ; Stephens, B.M. ; Stukel, M.R.
Title
CCE V: Primary production, mesozooplankton grazing, and the biological pump in the California Current Ecosystem: Variability and response to El Niño
Type
$loc['typeJournal Article']
Year
2018
Publication
Deep Sea Research Part I: Oceanographic Research Papers
Abbreviated Journal
Deep Sea Research Part I: Oceanographic Research Papers
Volume
140
Issue
Pages
52-62
Keywords
Carbon export ; Fecal pellets ; Sinking particles ; Interannual variability ; Net primary productivity ; Eastern boundary upwelling system
Abstract
Predicting marine carbon sequestration in a changing climate requires mechanistic understanding of the processes controlling sinking particle flux under different climatic conditions. The recent occurrence of a warm anomaly (2014-2015) followed by an El Nino (2015-2016) in the southern sector of the California Current System presented an opportunity to analyze changes in the biological carbon pump in response to altered climate forcing. We compare primary production, mesozooplankton grazing, and carbon export from the euphotic zone during quasi-Lagrangian experiments conducted in contrasting conditions: two cruises during warm years – one during the warm anomaly in 2014 and one toward the end of El Nino 2016 – and three cruises during El Ninoneutral years. Results showed no substantial differences in the relationships between vertical carbon export and its presumed drivers (primary production, mesozooplankton grazing) between warm and neutral years. Mesozooplankton fecal pellet enumeration and phaeopigment measurements both showed that fecal pellets were the dominant contributor to export in productive upwelling regions. In more oligotrophic regions, fluxes were dominated by amorphous marine snow with negligible pigment content. We found no evidence for a significant shift in the relationship between mesozooplankton grazing rate and chlorophyll concentration. However, massspecific grazing rates were lower at low-to-moderate chlorophyll concentrations during warm years relative to neutral years. We also detected a significant difference in the relationship between phytoplankton primary production and photosynthetically active radiation between years: at similar irradiance and nutrient concentrations, productivity decreased during the warm events. Whether these changes resulted from species composition changes remains to be determined. Overall, our results suggest that the processes driving export remain similar during different climate conditions, but that species compositional changes or other structural changes require further attention.
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
0967-0637
ISBN
Medium
Area
Expedition
Conference
Funding
Approved
$loc['no']
Call Number
COAPS @ user @
Serial
1021
Permanent link to this record
Author
Stukel, M.R. ; Kelly, T.B.
Title
The carbon: 234Thorium ratios of sinking particles in the California current ecosystem 2: Examination of a thorium sorption, desorption, and particle transport model
Type
$loc['typeJournal Article']
Year
Publication
Marine Chemistry
Abbreviated Journal
Marine Chemistry
Volume
Issue
Pages
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
0304-4203
ISBN
Medium
Area
Expedition
Conference
Funding
Approved
$loc['no']
Call Number
COAPS @ user @
Serial
1037
Permanent link to this record
Author
Laurencin, C. ; Misra, V.
Title
Characterizing the Variations of the motion of the North Atlantic tropical cyclones
Type
$loc['typeJournal Article']
Year
2018
Publication
Meteorology and Atmospheric Physics
Abbreviated Journal
Meteorol Atmos Phys
Volume
130
Issue
303
Pages
1-12
Keywords
climatology ; interannual scales ; environment
Abstract
In this study, we examine the seasonal and interannual variability of the North Atlantic (NATL) tropical cyclone (TC) motion from the historical Hurricane Database (HURDAT2) over the period 1988-2014. We characterize these motions based on their position, lifecycle, and seasonal cycle. The main findings of this study include: (1) of the 11,469 NATL TC fixes examined between 1988 and 2014, 81% of them had a translation speed of < 20 mph; (2) TCs in the deep tropics of the NATL are invariably slow-moving in comparison with TCs in higher latitudes. Although fast-moving TCs (> 40 mph) are exclusively found north of 30 N, the slow-moving TCs have a wide range of latitude. This is largely a consequence of the background steering flow being weaker (stronger) in the tropical (higher) latitudes with a minimum around the subtropical latitudes of NATL; (3) there is an overall decrease in the frequency of all categories of translation speed of TCs in warm relative to cold El Niño Southern Oscillation (ENSO) years. However, in terms of the percentage change, TCs with a translation speed in the range of 10-20 mph display the most change (42%) in warm relative to cold ENSO years; and (4) there is an overall decrease in frequency across all categories of TC translation speed in small relative to large Atlantic Warm Pool years, but in terms of percentage change in the frequency of TCs, there is a significant and comparable change in the frequency over a wider range of translation speeds than the ENSO composites. This last finding suggests that Atlantic Warm Pool variations have a more profound impact on the translation speed of Atlantic TCs than ENSO.
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 @ rl18 @
Serial
991
Permanent link to this record