Estimating Subpycnocline Density Fluctuations in the California Current Region from Upper Ocean Observations

1994 ◽  
Author(s):  
Robert L. Haney ◽  
Robert A. Hale ◽  
Curtis A. Collins
Keyword(s):  
California Current ◽  
Density Fluctuations ◽  
Upper Ocean ◽  
Current Region ◽  
Ocean Observations

Ocean Conditions and the Intensification of three Major Atlantic Hurricanes in 2017

2021 ◽  
Author(s):  
Ricardo Domingues ◽  
Matthieu Le Hénaff ◽  
George Halliwell ◽  
Jun A. Zhang ◽  
Francis Bringas ◽  
...  
Keyword(s):  
North Atlantic Ocean ◽  
Heat Content ◽  
Thermal Conditions ◽  
Time Frame ◽  
Upper Ocean ◽  
Tropical North Atlantic ◽  
Ocean Conditions ◽  
Atlantic Hurricanes ◽  
Numerical Model Experiments ◽  
Ocean Observations

AbstractMajor Atlantic hurricanes Irma, Jose, and Maria of 2017 reached their peak intensity in September while traveling over the tropical North Atlantic Ocean and Caribbean Sea, where both atmospheric and ocean conditions were favorable for intensification. In-situ and satellite ocean observations revealed that conditions in these areas exhibited: (i) sea surface temperatures above 28°C; (ii) upper-ocean heat content above 60 kJ cm-2; and (iii) the presence of low-salinity barrier layers associated with a larger-than-usual extension of the Amazon and Orinoco riverine plumes. Proof-of-concept coupled ocean-hurricane numerical model experiments demonstrated that the accurate representation of such ocean conditions led to an improvement in the simulated intensity of Hurricane Maria for the 3 days preceding landfall in Puerto Rico, when compared to an experiment without the assimilation of ocean observations. Without the assimilation of ocean observations, upper-ocean thermal conditions were generally colder than observations, resulting in reduced air-sea enthalpy fluxes - enthalpy fluxes are more realistically simulated when the upper-ocean temperature and salinity structure is better represented in the model. Our results further showed that different components of the ocean observing system provide valuable information in support of improved TC simulations, and that assimilation of underwater glider observations alone provided the largest improvement of the total improvement over the 24-hour time frame before landfall. Our results therefore indicated that ocean conditions were relevant for more realistically simulating Hurricane Maria’s intensity. However, further research based on a comprehensive set of hurricane cases is required to confirm robust improvements to forecast systems.

Sustained Ocean Observations from Merchant Marine Vessels

2001 ◽  
Vol 35 (3) ◽  
pp. 38-42 ◽  
Author(s):  
Tom Rossby
Keyword(s):  
Upper Ocean ◽  
Atmospheric Conditions ◽  
Merchant Marine ◽  
Accurate Picture ◽  
Weather And Climate ◽  
The Mean ◽  
New Generation ◽  
Marine Vessels ◽  
Ocean Observations ◽  
Mean State

Merchant marine vessels have provided invaluable information about weather and climate over the seas. In this note, it is shown how these vessels also contribute to ocean research through systematic surveys of upper ocean temperature, salinity and currents. By repeatedly sampling a particular route, one can obtain an accurate picture of the mean state of the ocean and where and how it varies. With a few examples drawn from our own work we show how commercial shipping and cruise vessels, with their unparalleled access to the oceans, could give society far more extensive and valuable information about upper ocean and atmospheric conditions on a regular basis. But for this to happen, a new generation of ocean instrumentation needs to be developed that is optimized for completely automatic and unattended operation on such vessels. It also means working with the merchant marine community to develop guidelines and procedures for future cooperative efforts.

Mesoscale to Submesoscale Transition in the California Current System. Part I: Flow Structure, Eddy Flux, and Observational Tests

2008 ◽  
Vol 38 (1) ◽  
pp. 29-43 ◽  
Author(s):  
X. Capet ◽  
J. C. McWilliams ◽  
M. J. Molemaker ◽  
A. F. Shchepetkin
Keyword(s):  
Flow Structure ◽  
Current System ◽  
Mesoscale Eddy ◽  
California Current ◽  
Upper Ocean ◽  
Surface Boundary ◽  
Surface Boundary Layer ◽  
California Current System ◽  
System Part ◽  
Wind Driven Currents

Abstract In computational simulations of an idealized subtropical eastern boundary upwelling current system, similar to the California Current, a submesoscale transition occurs in the eddy variability as the horizontal grid scale is reduced to O(1) km. This first paper (in a series of three) describes the transition in terms of the emergent flow structure and the associated time-averaged eddy fluxes. In addition to the mesoscale eddies that arise from a primary instability of the alongshore, wind-driven currents, significant energy is transferred into submesoscale fronts and vortices in the upper ocean. The submesoscale arises through surface frontogenesis growing off upwelled cold filaments that are pulled offshore and strained in between the mesoscale eddy centers. In turn, some submesoscale fronts become unstable and develop submesoscale meanders and fragment into roll-up vortices. Associated with this phenomenon are a large vertical vorticity and Rossby number, a large vertical velocity, relatively flat horizontal spectra (contrary to the prevailing view of mesoscale dynamics), a large vertical buoyancy flux acting to restratify the upper ocean, a submesoscale energy conversion from potential to kinetic, a significant spatial and temporal intermittency in the upper ocean, and material exchanges between the surface boundary layer and pycnocline. Comparison with available observations indicates that submesoscale fronts and instabilities occur widely in the upper ocean, with characteristics similar to the simulations.

Impact of Assimilating Underwater Glider Data on Hurricane Gonzalo (2014) Forecasts

2017 ◽  
Vol 32 (3) ◽  
pp. 1143-1159 ◽  
Author(s):  
Jili Dong ◽  
Ricardo Domingues ◽  
Gustavo Goni ◽  
George Halliwell ◽  
Hyun-Sook Kim ◽  
...  
Keyword(s):  
Initial Conditions ◽  
Storm Track ◽  
Upper Ocean ◽  
Underwater Glider ◽  
Intensity Forecast ◽  
Spatial Coverage ◽  
Ocean Conditions ◽  
The Impact ◽  
Ocean Observations ◽  
Limited Coverage

Abstract The initialization of ocean conditions is essential to coupled tropical cyclone (TC) forecasts. This study investigates the impact of ocean observation assimilation, particularly underwater glider data, on high-resolution coupled TC forecasts. Using the coupled Hurricane Weather Research and Forecasting (HWRF) Model–Hybrid Coordinate Ocean Model (HYCOM) system, numerical experiments are performed by assimilating underwater glider observations alone and with other standard ocean observations for the forecast of Hurricane Gonzalo (2014). The glider observations are able to provide valuable information on subsurface ocean thermal and saline structure, even with their limited spatial coverage along the storm track and the relatively small amount of data assimilated. Through the assimilation of underwater glider observations, the prestorm thermal and saline structures of initial upper-ocean conditions are significantly improved near the location of glider observations, though the impact is localized because of the limited coverage of glider data. The ocean initial conditions are best represented when both the standard ocean observations and the underwater glider data are assimilated together. The barrier layer and the associated sharp density gradient in the upper ocean are successfully represented in the ocean initial conditions only with the use of underwater glider observations. The upper-ocean temperature and salinity forecasts in the first 48 h are improved by assimilating both underwater glider and standard ocean observations. The assimilation of glider observations alone does not make a large impact on the intensity forecast due to their limited coverage along the storm track. The 126-h intensity forecast of Hurricane Gonzalo is improved moderately through assimilating both underwater glider data and standard ocean observations.

Forecasting and reanalysis in the Monterey Bay/California Current region for the Autonomous Ocean Sampling Network-II experiment

2009 ◽  
Vol 56 (3-5) ◽  
pp. 127-148 ◽  
Author(s):  
P.J. Haley ◽  
P.F.J. Lermusiaux ◽  
A.R. Robinson ◽  
W.G. Leslie ◽  
O. Logoutov ◽  
...  
Keyword(s):  
California Current ◽  
Monterey Bay ◽  
Sampling Network ◽  
Current Region ◽  
Ocean Sampling

Autonomous Profiling Floats: Workhorse for Broad-scale Ocean Observations

2004 ◽  
Vol 38 (2) ◽  
pp. 21-29 ◽  
Author(s):  
Dean Roemmich ◽  
Stephen Riser ◽  
Russ Davis ◽  
Yves Desaubies
Keyword(s):  
New Technology ◽  
Central Element ◽  
Upper Ocean ◽  
Depth Range ◽  
Satellite Measurements ◽  
Argo Data ◽  
Argo Float ◽  
The Tropics ◽  
Ocean Observations ◽  
Broad Scale

The autonomous profiling float has been a revolutionary development in oceanography, enabling global broad-scale ocean observations of temperature, salinity, velocity, and additional variables. The Argo float array applies this new technology to provide unprecedented measurements of the global upper ocean in near real time, with no period of exclusive use. It builds on its predecessors, the upper ocean thermal networks of the 1970s to 1990s—extending the spatial domain and depth range, improving the accuracy, and adding salinity and velocity. Precision satellite measurements of sea surface height, as made by the Jason-1 altimeter, combine with Argo data in a dynamically complementary description of sea level variability and its subsurface causes. The broad-scale Argo float array is a central element in the international infrastructure for ocean research. A comprehensive ocean observing system can be constructed from floats, together with satellite measurements, improved measurements of air-sea fluxes, moored time-series in the tropics and other special locations, shipboard hydrography, and high resolution measurements in fronts, eddies and boundary currents from autonomous gliders. One of the primary objectives of the observing system is to close the oceanic budgets of momentum, heat, and freshwater on seasonal and longer time-scales in order to understand the role of the ocean in the climate system.

Ecosystem-based management affecting Brandt's Cormorant resources and populations in the central California Current region

2018 ◽  
Vol 217 ◽  
pp. 407-418 ◽  
Author(s):  
David G. Ainley ◽  
Jarrod A. Santora ◽  
Phillip J. Capitolo ◽  
John C. Field ◽  
Jessie N. Beck ◽  
...  
Keyword(s):  
California Current ◽  
Central California ◽  
Ecosystem Based Management ◽  
Current Region
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