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Estimating Subsurface Horizontal And Vertical Velocities From Sea-Surface Temperature, J. H. Lacasce, A. Mahadevan
Estimating Subsurface Horizontal And Vertical Velocities From Sea-Surface Temperature, J. H. Lacasce, A. Mahadevan
Journal of Marine Research
We examine a dynamical method for estimating subsurface fields (density, pressure, horizontal and vertical velocities) in the upper ocean using sea-surface temperature (SST) and a climatological estimate of the stratification. The method derives from the "surface quasi-geostrophic" (SQG) approximation. The SST is used to generate a potential vorticity (PV) field which is then inverted for the pressure. We examine first the standard SQG model, in which the PV is assumed trapped in a delta-function layer at the surface. We then modify the model by introducing a subsurface PV which is proportional to the surface density and decays exponentially with depth. …
Accounting For Unresolved Spatial Variability In Marine Ecosystems Using Time Lags, Philip J. Walhead, Adrian P. Martin, Meric A. Srokosz, Mike J. R. Fasham
Accounting For Unresolved Spatial Variability In Marine Ecosystems Using Time Lags, Philip J. Walhead, Adrian P. Martin, Meric A. Srokosz, Mike J. R. Fasham
Journal of Marine Research
The formulation and calibration of models is a vital method for probing and predicting the behavior of marine ecosystems. The ability to do this may suffer, however, if the calibrating data set is subject to significant spatial variability between samples that is not resolved in the model. We propose that some of this variability might be accounted for by variable time lags between sampled water masses which are otherwise assumed to follow a common pattern of ecosystem variability (dynamical trajectory). Using twin tests of fitting models to simulated data sets, we show that realistic levels of meso/sub-mesoscale variability in time …
Sensitivity Of The Meridional Transport In A 1.5-Layer Ocean Model To Localized Mass Sources, C. Herbaut, J. Sirven, J. Deshayes
Sensitivity Of The Meridional Transport In A 1.5-Layer Ocean Model To Localized Mass Sources, C. Herbaut, J. Sirven, J. Deshayes
Journal of Marine Research
The response of a 1.5-layer ocean model forced by localized stochastic mass sources is studied. The focus is on the sensitivity of the spectral characteristics of the meridional transport to the location and the extent of the source region. In all the experiments, performed in hemispheric and interhemispheric basins, the spectra show a peak at interannual time scale revealing the existence of an oscillation. The period of the oscillation is defined by the zonal extent of the forcing, whereas its amplitude is affected by its location. When the source region is located in the northwestern corner of the basin, the …
Linking Arenicola Marina Irrigation Behavior To Oxygen Transport And Dynamics In Sandy Sediments, Karen Timmermann, Gary T. Banta, Ronnie N. Glud
Linking Arenicola Marina Irrigation Behavior To Oxygen Transport And Dynamics In Sandy Sediments, Karen Timmermann, Gary T. Banta, Ronnie N. Glud
Journal of Marine Research
In this study we examine how the irrigation behavior of the common lugworm Arenicola marina affects the distribution, transport and dynamics of oxygen in sediments using microelectrodes, planar optodes and diagenetic modeling. The irrigation pattern was characterized by a regular recurring periods of active irrigation lasting approximately 15 min separated by a 15 min rest period. The mean pumping rate during irrigation was 52 ml h−1. Oxygen dynamics and distribution around the tail shaft was closely related to irrigation pattern but independent of pumping rate. During irrigation the oxygen concentration in the burrow was high (>80% air …
Beam Attenuation And Chlorophyll Concentration As Alternative Optical Indices Of Phytoplankton Biomass, Michael J. Behrenfeld, Emmanual Boss
Beam Attenuation And Chlorophyll Concentration As Alternative Optical Indices Of Phytoplankton Biomass, Michael J. Behrenfeld, Emmanual Boss
Journal of Marine Research
Chlorophyll has long functioned as the prominent field metric for phytoplankton biomass, but its variability can be strongly influenced by (even dominated by) physiological shifts in intracellular pigmentation in response to changing growth conditions (light, nutrients, temperature). The particulate beam attenuation coefficient (cp) may offer an alternative optical measure of phytoplankton biomass that is readily assessed in situ and relatively insensitive to changes in intracellular pigment content. Unlike chlorophyll, however, cp is not uniquely associated with phytoplankton and varies as well with changes in inorganic, detrital, and heterotrophic particles. In open ocean environments, particles in the …
Variability In The Indian Ocean Circulation And Salinity And Its Impact On Sst Anomalies During Dipole Events, Bijoy Thompson, C. Gnanaseelan, P. S. Salvekar
Variability In The Indian Ocean Circulation And Salinity And Its Impact On Sst Anomalies During Dipole Events, Bijoy Thompson, C. Gnanaseelan, P. S. Salvekar
Journal of Marine Research
The GFDL Modular Ocean Model (MOM4) has been used to understand the variability of the Indian Ocean circulation and salinity during Indian Ocean Dipole events. The model simulations are compared with HadISST, SODA and ECCO data sets. During the positive dipole years, the climatological cyclonic circulation in the Bay of Bengal weakens or is replaced by an anticyclonic circulation. The interannual variability in the Wyrtki Jet and Bay of Bengal circulation has significant influence on fresh water transport between the equatorial Indian Ocean and Bay of Bengal. The salinity anomalies in the equatorial Indian Ocean are significant during the positive …
Tidal Energy In The Bering Sea, M. G. G. Foreman, P. F. Cummins, J. Y. Cherniawsky, Phyllis Stabeno
Tidal Energy In The Bering Sea, M. G. G. Foreman, P. F. Cummins, J. Y. Cherniawsky, Phyllis Stabeno
Journal of Marine Research
Tidal harmonics computed from TOPEX/POSEIDON altimetry are assimilated into a barotropic, finite element model of the Bering Sea whose accuracy is evaluated though comparisons with independent bottom pressure gauges. The model is used to estimate energy fluxes through each of the Aleutian Passes and Bering Strait and to construct an energy budget for the major tidal constituents. The finite element model does not conserve mass locally and this is shown to give rise to an additional term in the energy budget whose contribution is significant for the prior model, but which is reduced substantially with the assimilation technique. Though the …