Baroclinic Effect on Modeling Deep Flow in Brown Passage, BC, Canada

Brown Passage is a deep (up to 200 m) ocean channel connecting the western offshore waters of Hecate Strait and Dixon Entrance on the Pacific continental shelf with the eastern inland waters of Chatham Sound in Northern British Columbia, Canada. A high-resolution 3D finite difference hydrodynamic model, COastal CIRculation and SEDiment transport Model (COCIRM-SED), was developed in 2010 and 2013 to determine the tidal and wind-driven currents of this area. The barotropic model results for ocean currents were found to be in reasonably good agreement with the historical ocean current observations at near-surface and middle depth available for Brown Passage. Operated from October 2014 to April 2015, the first modern oceanographic measurement program in Brown Passage found surprisingly strong near-bottom currents (the 99th percentile current speed reaches 53 cm/s at 196 m). As a result, the COCIRM-SED model was modified and rerun, with the most important change incorporating water density/salinity fields as modeled variables. This change led to considerable improvements in the ability of the model to generate episodes of relatively strong currents in the bottom layers. The bottom intensification in ocean currents in Brown Passage is shown to be due to semi-diurnal internal tides, which were not previously included in the barotropic version of the 3D model. This finding for the near-bottom flow from the qualitative modeling study is important for applications of the potential sediment deposition and resuspension studies.

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POTENSI ENERGI ARUS LAUT SEBAGAI ENERGI TERBARUKAN DI SELAT LOMBOK BERDASARKAN DATA INSTANT WEST MOORING DEPLOYMENT 1

JURNAL GEOLOGI KELAUTAN ◽

10.32693/jgk.14.2.2016.357 ◽

2017 ◽

Vol 14 (2) ◽

Author(s):

Yogo Pratomo ◽

Widodo Setiyo Pranowo ◽

Sahat Monang Simanjuntak

Keyword(s):

Renewable Energy ◽

Water Depth ◽

Current Speed ◽

Ocean Currents ◽

Ocean Current ◽

The Pacific ◽

Through Flow ◽

The Indian Ocean ◽

The Pacific Ocean ◽

Harmonic Components

Selat Lombok merupakan salah satu perlintasan massa air laut dunia, yang mengalir dari Samudera Pasifik menuju ke Samudera Hindia yang disebut sebagai Arus Lintas Indonesia (ARLINDO). Hal ini terbukti dengan adanya komponen harmonik periode panjang yang di pengaruhi oleh Matahari (SA, SSA), dan dipengaruhi Bulan (MSF). Hasil rekaman mooring selama 1,5 tahun, selat ini memiliki kecepatan arus harmonik rata-rata sebesar 0,25219 m/dt di kedalaman 100 meter. Arus laut merupakan salah satu energi baru terbarukan yang dapat di manfaatkan sebagai pembangkit listrik. Arus laut diolah dengan menggunakan modul toolbox T-Tide 1,3 beta, dan menghasilkan arus harmonik dan arus non harmonik. Berdasarkan komputasi skenario pertama, dengan menggunakan turbin Helix LC 500 dan menghasilkan listrik 3,56 KW (harmonic), dan 1,86 KW (non harmonik) dengan kecepatan arus terbesar terjadi pada kedalaman 146,31 meter. Nilai kecepatan arus rata-rata terdapat pada kedalaman 178,31 meter dengan daya yang dihasilkan sebesar 92,17 W pada kondisi arus non harmonik. Kecepatan arus rata-rata pada kondisi arus harmonik terdapat pada kedalaman 162,31 meter, dengan daya yang dihasilkan sebesar 32,943 W.Kata Kunci : arus laut, energi baru terbarukan, Selat Lombok, INSTANT West Mooring.Lombok Strait is one of seawater mass outlet, flowing from the Pacific Ocean toward the Indian Ocean called as Indonesian Through Flow (ITF). It is proven by long period of harmonic components influenced by sun (SA, SSA) and moon (MSF). The result of mooring record for 1.5 years, this strait has average speed of the harmonic ocean current is 0.25219 m/s at 100 meters water depth. Ocean current is one of renewable energy that can be used for generating power electric. Ocean currents processed by using T-tide matlab toolbox 1.3 beta to identified the harmonic and non harmonic currents. Based on first scenario of the computer conversion, by using a Helix turbine LC 500 and produce an electricity energy about 3.56 KW (harmonic), and 1.86 KW (non harmonic) ocean currents, with the maximum current speed at the 146.31 meters water depth. The average of current speed average found at 178.31 meters water depth, and it produces a power of 92.17 W (non harmonic). The current speed averages from the harmonic condition is found at 162.31 meters water depth, which can produce a power about 32.943 W.Keyword : ocean currents, potential renewable energy, Lombok Strait, INSTANT West Mooring.

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Shipborne MAX-DOAS measurements for validation of TROPOMI NO<sub>2</sub> products

Atmospheric Measurement Techniques ◽

10.5194/amt-13-1413-2020 ◽

2020 ◽

Vol 13 (3) ◽

pp. 1413-1426 ◽

Cited By ~ 3

Author(s):

Ping Wang ◽

Ankie Piters ◽

Jos van Geffen ◽

Olaf Tuinder ◽

Piet Stammes ◽

...

Keyword(s):

Column Density ◽

Transport Model ◽

Massively Parallel ◽

Optical Absorption Spectroscopy ◽

Vertical Column ◽

Chemistry Transport Model ◽

The Pacific ◽

Tropospheric No2 ◽

Vertical Column Density ◽

Good Agreement

Abstract. Tropospheric NO2 and stratospheric NO2 vertical column densities are important TROPOspheric Monitoring Instrument (TROPOMI) data products. In order to validate the TROPOMI NO2 products, KNMI Multi-AXis Differential Optical Absorption Spectroscopy (MAX-DOAS) instruments have measured NO2 on ship cruises over the Atlantic and the Pacific oceans. The MAX-DOAS instruments have participated in five cruises on board RV Sonne (in 2017 and 2019) and RV Maria S. Merian (in 2018). The MAX-DOAS measurements were acquired over 7 months and spanned about 90∘ in latitude and 300∘ in longitude. During the cruises aerosol measurements from Microtops sun photometers were also taken. The MAX-DOAS measured stratospheric NO2 columns between 1.5×1015 and 3.5×1015 molec cm−2 and tropospheric NO2 up to 0.6×1015 molec cm−2. The MAX-DOAS stratospheric NO2 vertical column densities have been compared with TROPOMI stratospheric NO2 vertical column densities and the stratospheric NO2 vertical column densities simulated by the global chemistry Transport Model, version 5, Massively Parallel model (TM5-MP). Good correlation is found between the MAX-DOAS and TROPOMI and TM5 stratospheric NO2 vertical column densities, with a correlation coefficient of 0.93 or larger. The TROPOMI and TM5 stratospheric NO2 vertical column densities are about 0.4×1015 molec cm−2 (19 %) higher than the MAX-DOAS measurements. The TROPOMI tropospheric NO2 also has good agreement with the MAX-DOAS measurements. The tropospheric NO2 vertical column density is as low as 0.5×1015 molec cm−2 over remote oceans.

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Modeling and Numerical Simulation of a Buoyancy Controlled Ocean Current Turbine

International Marine Energy Journal ◽

10.36688/imej.4.47-58 ◽

2021 ◽

Vol 4 (2) ◽

pp. 47-58

Author(s):

Arezoo Hasankhani ◽

James VanZwieten ◽

Yufei Tang ◽

Broc Dunlap ◽

Alexandra De Luera ◽

...

Keyword(s):

Numerical Simulation ◽

High Energy ◽

Ocean Currents ◽

High Energy Density ◽

Ocean Current ◽

Fault Models ◽

Near Surface ◽

Renewable Power ◽

Flow Speeds ◽

Current Turbine

Increased global renewable power demands and the high energy density of ocean currents have motivated the development of ocean current turbines (OCTs). These compliantly mooring systems will maintain desired near-surface operating depths using variable buoyancy, lifting surface, sub-sea winches, and/or surface buoys. This paper presents a complete numerical simulation of a 700 kW variable buoyancy controlled OCT that includes detailed turbine system, inflow, actuator (i.e., generator and variable buoyancy), sensor, and fault models. Simulation predictions of OCT performance are made for normal, hurricane, and fault scenarios. Results suggest this OCT can operate between depths of 38 m to 329 m for all homogeneous flow speeds between 1.0-2.5 m/s. Fault scenarios show that rotor braking results in a rapid vertical OCT system assent and that blade pitch faults create power fluctuations apparent in the frequency domain. Finally, simulated OCT operations in measured ocean currents (i.e., normal and hurricane conditions) quantify power statistics and system behavior typical and extreme conditions.

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Feedback of mesoscale ocean currents on atmospheric winds in high-resolution coupled models and implications for the forcing of ocean-only models

10.5194/os-2017-24 ◽

2017 ◽

Cited By ~ 3

Author(s):

Rafael Abel ◽

Claus W. Böning ◽

Richard J. Greatbatch ◽

Helene T. Hewitt ◽

Malcolm J. Roberts

Keyword(s):

Climate Model ◽

Global Climate Model ◽

Surface Wind ◽

Ocean Currents ◽

Global Ocean ◽

Ocean Current ◽

Western Boundary ◽

Coupling Coefficients ◽

Coupled Models ◽

Near Surface

Abstract. The repercussions of surface ocean currents for the near-surface wind and the air-sea momentum flux are investigated in two versions of a global climate model with eddying ocean. The focus is on the effect of mesoscale ocean current features at scales of less than 150 km, by considering high-pass filtered, monthly-mean model output fields. We find a clear signature of a mesoscale oceanic imprint in the wind fields over the energetic areas of the oceans, particularly along the extensions of the western boundary currents and the Antarctic Circumpolar Current. These areas are characterized by a positive correlation between mesoscale perturbations in the curl of the surface currents and the wind curl. The coupling coefficients are spatially non-uniform and show a pronounced seasonal cycle. The positive feedback of mesoscale current features on the near-surface wind acts in opposition to their damping effect on the wind stress. A tentative incorporation of this feedback in the surface stress formulation of an eddy-permitting global ocean-only model leads to a gain in the kinetic energy of up to 10 %, suggesting a fundamental shortcoming of present ocean model configurations.

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Investigating Alaskan methane and carbon dioxide fluxes using measurements from the CARVE tower

Atmospheric Chemistry and Physics ◽

10.5194/acp-16-5383-2016 ◽

2016 ◽

Vol 16 (8) ◽

pp. 5383-5398 ◽

Cited By ~ 14

Author(s):

Anna Karion ◽

Colm Sweeney ◽

John B. Miller ◽

Arlyn E. Andrews ◽

Roisin Commane ◽

...

Keyword(s):

Carbon Dioxide ◽

Transport Model ◽

Carbon Sources ◽

Wrf Model ◽

Surface Fluxes ◽

Carbon Dioxide Fluxes ◽

Near Surface ◽

Northern High Latitude ◽

Carbon Dioxide Co2 ◽

Good Agreement

Abstract. Northern high-latitude carbon sources and sinks, including those resulting from degrading permafrost, are thought to be sensitive to the rapidly warming climate. Because the near-surface atmosphere integrates surface fluxes over large ( ∼  500–1000 km) scales, atmospheric monitoring of carbon dioxide (CO2) and methane (CH4) mole fractions in the daytime mixed layer is a promising method for detecting change in the carbon cycle throughout boreal Alaska. Here we use CO2 and CH4 measurements from a NOAA tower 17 km north of Fairbanks, AK, established as part of NASA's Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE), to investigate regional fluxes of CO2 and CH4 for 2012–2014. CARVE was designed to use aircraft and surface observations to better understand and quantify the sensitivity of Alaskan carbon fluxes to climate variability. We use high-resolution meteorological fields from the Polar Weather Research and Forecasting (WRF) model coupled with the Stochastic Time-Inverted Lagrangian Transport model (hereafter, WRF-STILT), along with the Polar Vegetation Photosynthesis and Respiration Model (PolarVPRM), to investigate fluxes of CO2 in boreal Alaska using the tower observations, which are sensitive to large areas of central Alaska. We show that simulated PolarVPRM–WRF-STILT CO2 mole fractions show remarkably good agreement with tower observations, suggesting that the WRF-STILT model represents the meteorology of the region quite well, and that the PolarVPRM flux magnitudes and spatial distribution are generally consistent with CO2 mole fractions observed at the CARVE tower. One exception to this good agreement is that during the fall of all 3 years, PolarVPRM cannot reproduce the observed CO2 respiration. Using the WRF-STILT model, we find that average CH4 fluxes in boreal Alaska are somewhat lower than flux estimates by Chang et al. (2014) over all of Alaska for May–September 2012; we also find that enhancements appear to persist during some wintertime periods, augmenting those observed during the summer and fall. The possibility of significant fall and winter CO2 and CH4 fluxes underscores the need for year-round in situ observations to quantify changes in boreal Alaskan annual carbon balance.

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The evolving response of mesopelagic fishes to declining midwater oxygen concentrations in the southern and central California Current

ICES Journal of Marine Science ◽

10.1093/icesjms/fsy154 ◽

2018 ◽

Vol 76 (3) ◽

pp. 626-638 ◽

Cited By ~ 2

Author(s):

J Anthony Koslow ◽

Pete Davison ◽

Erica Ferrer ◽

S Patricia A Jiménez Rosenberg ◽

Gerardo Aceves-Medina ◽

...

Keyword(s):

Baja California ◽

Southern Oscillation ◽

Global Climate ◽

California Current ◽

Deep Ocean ◽

Near Surface ◽

Oxygen Minimum Zones ◽

The North ◽

The Pacific ◽

Oxygen Concentrations

Abstract Declining oxygen concentrations in the deep ocean, particularly in areas with pronounced oxygen minimum zones (OMZs), are a growing global concern related to global climate change. Its potential impacts on marine life remain poorly understood. A previous study suggested that the abundance of a diverse suite of mesopelagic fishes off southern California was closely linked to trends in midwater oxygen concentration. This study expands the spatial and temporal scale of that analysis to examine how mesopelagic fishes are responding to declining oxygen levels in the California Current (CC) off central, southern, and Baja California. Several warm-water mesopelagic species, apparently adapted to the shallower, more intense OMZ off Baja California, are shown to be increasing despite declining midwater oxygen concentrations and becoming increasingly dominant, initially off Baja California and subsequently in the CC region to the north. Their increased abundance is associated with warming near-surface ocean temperature, the warm phase of the Pacific Decadal oscillation and Multivariate El Niño-Southern Oscillation Index, and the increased flux of Pacific Equatorial Water into the southern CC.

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Variability of springtime transpacific pollution transport during 2000–2006: the INTEX-B mission in the context of previous years

Atmospheric Chemistry and Physics ◽

10.5194/acp-10-1345-2010 ◽

2010 ◽

Vol 10 (3) ◽

pp. 1345-1359 ◽

Cited By ~ 16

Author(s):

G. G. Pfister ◽

L. K. Emmons ◽

D. P. Edwards ◽

A. Arellano ◽

T. Campos ◽

...

Keyword(s):

Transport Model ◽

Pollution Transport ◽

Chemistry Transport Model ◽

Pollution Levels ◽

Annual Variability ◽

Source Regions ◽

Time Period ◽

The Pacific ◽

The Us ◽

Transport Experiment

Abstract. We analyze the transport of pollution across the Pacific during the NASA INTEX-B (Intercontinental Chemical Transport Experiment Part B) campaign in spring 2006 and examine how this year compares to the time period for 2000 through 2006. In addition to aircraft measurements of carbon monoxide (CO) collected during INTEX-B, we include in this study multi-year satellite retrievals of CO from the Measurements of Pollution in the Troposphere (MOPITT) instrument and simulations from the chemistry transport model MOZART-4. Model tracers are used to examine the contributions of different source regions and source types to pollution levels over the Pacific. Additional modeling studies are performed to separate the impacts of inter-annual variability in meteorology and dynamics from changes in source strength. Interannual variability in the tropospheric CO burden over the Pacific and the US as estimated from the MOPITT data range up to 7% and a somewhat smaller estimate (5%) is derived from the model. When keeping the emissions in the model constant between years, the year-to-year changes are reduced (2%), but show that in addition to changes in emissions, variable meteorological conditions also impact transpacific pollution transport. We estimate that about 1/3 of the variability in the tropospheric CO loading over the contiguous US is explained by changes in emissions and about 2/3 by changes in meteorology and transport. Biomass burning sources are found to be a larger driver for inter-annual variability in the CO loading compared to fossil and biofuel sources or photochemical CO production even though their absolute contributions are smaller. Source contribution analysis shows that the aircraft sampling during INTEX-B was fairly representative of the larger scale region, but with a slight bias towards higher influence from Asian contributions.

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Disturbance learning controller design for unmanned surface vehicle using LSTM technique of recurrent neural network

Journal of Intelligent & Fuzzy Systems ◽

10.3233/jifs-189622 ◽

2021 ◽

pp. 1-11

Author(s):

Sang-Ki Jeong ◽

Dea-Hyeong Ji ◽

Ji-Youn Oh ◽

Jung-Min Seo ◽

Hyeung-Sik Choi

Keyword(s):

Neural Network ◽

Control System ◽

Flow Velocity ◽

Recurrent Neural Network ◽

Pid Controller ◽

Short Term Memory ◽

Ocean Currents ◽

Ocean Current ◽

Movement Speed ◽

Marine Research

In this study, to effectively control small unmanned surface vehicles (USVs) for marine research, characteristics of ocean current were learned using the long short-term memory (LSTM) model algorithm of a recurrent neural network (RNN), and ocean currents were predicted. Using the results, a study on the control of USVs was conducted. A control system model of a small USV equipped with two rear thrusters and a front thruster arranged horizontally was designed. The system was also designed to determine the output of the controller by predicting the speed of the following currents and utilizing this data as a system disturbance by learning data from ocean currents using the LSTM algorithm of a RNN. To measure ocean currents on the sea when a small USV moves, the speed and direction of the ship’s movement were measured using speed, azimuth, and location (latitude and longitude) data from GPS. In addition, the movement speed of the fluid with flow velocity is measured using the installed flow velocity measurement sensor. Additionally, a control system was designed to control the movement of the USV using an artificial neural network-PID (ANN-PID) controller [12]. The ANN-PID controller can manage disturbances by adjusting the control gain. Based on these studies, the control results were analyzed, and the control algorithm was verified through a simulation of the applied control system [8, 9].

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A warm jet in a cold ocean

Nature Communications ◽

10.1038/s41467-021-22505-5 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Jennifer A. MacKinnon ◽

Harper L. Simmons ◽

John Hargrove ◽

Jim Thomson ◽

Thomas Peacock ◽

...

Keyword(s):

The Arctic ◽

Bering Strait ◽

Near Surface ◽

Ice Melt ◽

Beaufort Gyre ◽

The Pacific ◽

Climate Simulations ◽

Initial Evolution ◽

Forecast Models

AbstractUnprecedented quantities of heat are entering the Pacific sector of the Arctic Ocean through Bering Strait, particularly during summer months. Though some heat is lost to the atmosphere during autumn cooling, a significant fraction of the incoming warm, salty water subducts (dives beneath) below a cooler fresher layer of near-surface water, subsequently extending hundreds of kilometers into the Beaufort Gyre. Upward turbulent mixing of these sub-surface pockets of heat is likely accelerating sea ice melt in the region. This Pacific-origin water brings both heat and unique biogeochemical properties, contributing to a changing Arctic ecosystem. However, our ability to understand or forecast the role of this incoming water mass has been hampered by lack of understanding of the physical processes controlling subduction and evolution of this this warm water. Crucially, the processes seen here occur at small horizontal scales not resolved by regional forecast models or climate simulations; new parameterizations must be developed that accurately represent the physics. Here we present novel high resolution observations showing the detailed process of subduction and initial evolution of warm Pacific-origin water in the southern Beaufort Gyre.

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Long-term ocean acidification trends in coastal waters around Japan

Scientific Reports ◽

10.1038/s41598-021-84657-0 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Hiroshi Ishida ◽

Ryosuke S. Isono ◽

Jun Kita ◽

Yutaka W. Watanabe

Keyword(s):

Pacific Ocean ◽

Ocean Acidification ◽

Sea Of Japan ◽

Ocean Current ◽

The Sea Of Japan ◽

Marginal Seas ◽

The Pacific ◽

Activity Measurements ◽

The Pacific Ocean

AbstractThis study examines long-term ocean pH data to evaluate ocean acidification (OA) trends at two coastal research institutions located on the Sea of Japan and the Pacific Ocean. These laboratories are located away from the influences of large rivers and major industrial activity. Measurements were performed daily for the past 30 years (1980s–2010s). The average annual ocean pH for both sites showed generally negative trends. These trends were – 0.0032 and – 0.0068 year–1 (p < 0.001) at the Sea of Japan and Pacific Ocean sites, respectively. The trends were superimposed onto approximately 10-year oscillations, which appear to synchronize with the ocean current periodicity. At the Sea of Japan site, the ocean pH in the summer was higher, and the rate of OA was higher than during other seasons. Our results suggest that seasonality and ocean currents influence OA in the coastal areas of open oceans and can affect the coastal regions of marginal seas.

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