The mean circulation pattern and its mechanism over Caiwei Guyot (1308~5600 m) in the Northwest Pacific were studied utilizing three years of in‐situ data. A deep anticyclonic cap was found to enclose the entire guyot from its bottom up to a depth of 728 m, which is comprised of a stable but highly asymmetric anticyclonic circulation at the foot and a bottom‐trapped anticyclonic circulation over the

Historical hydrographic data reveal that low‐salinity water can detach from the Yellow River plume in summer. In this study, the mechanism of this detachment is examined using a three‐dimensional numerical model that reproduced the observed detachment, including the position and size of the detached low‐salinity water patch. Sensitivity experiments showed that tide‐induced residual currents and tidal

We explore dense water cascading (DWC), a type of bottom‐trapped gravity current, on multi‐decadal time scales using a pan‐Arctic regional ocean‐ice model. DWC is particularly important in the Arctic Ocean as the main mechanism of ventilation of interior waters when open ocean convection is blocked by strong density stratification. We identify the locations where the most intense DWC events occur and

The western tropical Pacific (WTP) exhibits pronounced large‐scale sea level anomalies (SLAs) during El Niño – Southern Oscillation (ENSO) events with amplitudes of ~0.1 m, exerting potential threats to many low‐lying islands. It is found that the sea level falling in El Niño condition is evidently stronger than the rising in La Niña condition. This SLA asymmetry in the WTP associated with ENSO is

The Atlantic Water (AW) inflow through Fram Strait is the largest oceanic heat source to the Arctic Ocean and undergoes substantial modifications in the Western Nansen Basin (WNB). Evaluation of the Mercator system in the WNB, using 1500 independent temperature‐salinity profiles and five years of mooring data, highlighted its performance in representing realistic AW inflow and hydrographic properties

Anadyr Strait, located at the northernmost reaches of the Bering Sea, influences pan‐Arctic climate through processes occurring in the strait as the Siberian Coastal Current carries water from the subpolar North Pacific Ocean into the western Arctic Ocean. A sharp sea surface temperature front near the Anadyr Strait segregates a tongue‐shaped mass of warm water from areas of cold‐water upwelling proximate

Data from repeat hydrographic surveys over the 25‐year period 1993 to 2017, together with satellite altimetry data, are used to quantify the temporal and spatial variability of the North Icelandic Irminger Current (NIIC), East Icelandic Current (EIC), and the water masses they advect around northern Iceland. We focus on the warm, salty Atlantic Water (AW) flowing northward through Denmark Strait and

The release of greenhouse gases from both natural and man‐made sites has been identified as a major cause of global climate change. Extensive work has addressed quantifying gas seeps in the terrestrial setting while little has been done to refine accurate methods for determining gas flux emerging through the seabed into the water column. This paper investigates large‐scale methane seepage from the

We investigate the lag between warm interannual Sea Surface Temperature (SST) events in the eastern‐equatorial Atlantic, the Atlantic Niños, and the occurrence of Benguela Niños along the southwestern Angolan coast. While it is commonly agreed that both events are associated with equatorial and subsequent coastal‐trapped wave propagations driven remotely by a relaxation of the trade‐winds, it is surprising

The Agulhas leakage of Indian Ocean waters into the Atlantic has been shown to be a key link in global ocean circulation and climate; an increased understanding of this process is therefore of more than just of local interest. While knowledge of the Agulhas leakage has increased over the past 30 years, the precise mechanisms at play and water properties transferred are still not sufficiently documented

Statistical properties of near‐surface horizontal velocity gradients are obtained from four drifter experiments conducted in the Gulf Mexico during Summer 2012 and Winter 2016. The data density provided by the near‐simultaneous deployments of 90‐326 surface drifters in each allows direct, drifter‐based estimates of the scale dependence of velocity gradients at separation scales ranging from 200 m to

The Southern Ocean is the largest region in which iron limits the growth of phytoplankton. However, a phytoplankton bloom thousands of square kilometres in area forms each spring‐summer in the Indian sector of the Southern Ocean, both above and to the east of the Kerguelen Plateau. The central region of the Kerguelen Plateau hosts the volcanically active islands, Heard and McDonald (HIMI), the former

Buoyant freshwater released at depth from under Greenland's marine‐terminating glaciers gives rise to vigorous buoyant discharge plumes adjacent to the termini. The water mass found down fjord formed by mixing of buoyant subglacial freshwater and ambient fjord water and subsequent modification by glacial ice melt in the ice mélange is referred to as subglacial water. It substantially affects both the

Repeat measurements of velocity and temperature profiles from the Container Motor Vessel (CMV) Oleander provide an unprecedented look into the variability on the New Jersey Shelf and upper continental slope. Here 1362 acoustic Doppler current profiler (ADCP) velocity sections collected between 1994 and 2018 are analyzed in both Eulerian and stream coordinate reference frames to characterize the mean

This study examines the potential impact of sub‐surface potential temperature and current conditions on the sea surface temperature (SST) and rainfall over the tropical region using Climate Forecast System version‐2 (CFSv2) ensemble seasonal reforecasts for 1958‐2014. The climatological difference of earlier period (1958–78; P58‐78) and later period (1994–2014; P94‐14) in January initialized reforecasts

The dynamics of physical and bio‐optical properties on the shelf and the shelf‐slope break areas offshore of the Delaware Bay were investigated. Compared to monthly means, there were elevated daily freshwater outflows. Glider observations demonstrated significant changes in bio‐optical properties before and after sampling fresher water masses. Prior to sampling fresher water masses, the glider observations

Given their ephemeral nature, eddies have proven difficult to study, with contrary results from field observations that typically sample at the center during a specific stage of an eddy lifespan. Using the natural occurring radionuclide 234Th, we examined particle fluxes within two cyclonic eddies (CEs) at different evolutionary stages (mature stage eddy, C2, and a decay stage eddy, C1) in the oligotrophic

We perform the first global analysis of the spatial footprints of storm surges, using observed and simulated storm surge data. Three different techniques are applied to quantify the spatial footprints: clustering analysis, percentage of co‐occurrence, and joint probability analysis. The capability of the simulated data to represent the observed storm surge footprints is demonstrated. Results lead to

Sea ice physical properties were determined at 21 first‐year ice (FYI) and 20 multiyear ice (MYI) stations in the Pacific sector of the Arctic during summer in 2008–2018. The bulk ice temperature was between −2.7 and −0.3 °C for FYI and between −1.7 and −0.2 °C for MYI. The bulk salinity was 0.4–3.2 practical salinity unit (psu) for FYI and 0.4–2.4 psu for MYI. A low‐salinity layer and an almost fresh

The Doppler frequency shift acquired by Synthetic Aperture Radar (SAR) contains information about ocean surface motion induced by waves and the underlying ocean currents in the radar range direction. An accurate estimate of the wave‐induced contribution is therefore required to derive a reliable estimation of the ocean surface current. In this study, we developed an empirical model for estimating the

Knowledge of ocean surface current at high resolutions is crucial for many applications. In addition to the classic satellite altimetry retrieval from Sea Surface Height (SSH), ocean surface currents can be retrieved from Sea Surface Temperature (SST) observations using a transfer function between SST and SSH. Previous works showed the potential of microwave SST observations to reconstruct ocean surface

Aeolian transport of mineral dust is one of the main inputs of iron (Fe) to the global ocean; however, the magnitude and biogeochemical impact of this supply depends on the solubility of the deposited dust. In particular, the effect of temperature on solubility of dust‐bound Fe has been scarcely investigated even though a seasonal gradient of sea surface temperature (SST) is a common feature in coastal

Upper‐ocean stratification strongly impacts vertical mixing and the heat flux between the ocean and atmosphere, especially under extreme conditions of tropical cyclones (TCs). Knowledge of pre‐storm stratification is important for accurate TC intensity prediction. In‐situ observations of the tropical ocean have significantly increased in the past decade. However, they are still too sparse to resolve

In this research temperature and salinity profiles in eddy‐centered coordinates obtained from satellite altimetry (eddy dataset distributed by AVISO+) are combined to document the mean three‐dimensional structures of cyclonic (CEs) and anticyclonic (AEs) eddies in the Lofoten Basin. For eddies of both polarities, significant eddy‐induced anomalies are concentrated within the zero vorticity radius and

This study investigates the impact of assimilation of Northwestern Tropical Pacific Ocean (NWTPO) moored currents observation system on low‐frequency (over a period of more than 90 days) current estimation. A low‐frequency scale‐selective ensemble optimal interpolation (EnOI) scheme is designed to assimilate the horizontally sparse moored currents into an eddy‐permitting ocean model. In this assimilation

We provide an assessment of the current and future states of Arctic sea ice simulated by the Community Earth System Model version 2 (CESM2). The CESM2 is the version of the CESM contributed to the sixth phase of the Coupled Model Intercomparison Project (CMIP6). We analyze changes in Arctic sea ice cover in two CESM2 configurations with differing atmospheric components: the CESM2(CAM6) and the CESM2(WACCM6)

A regional data‐constrained coupled ocean‐sea ice general circulation model and its adjoint are used to investigate mechanisms controlling the volume transport variability through Bering Strait during 2002 to 2013. Comprehensive time‐resolved sensitivity maps of Bering Strait transport to atmospheric forcing can be accurately computed with the adjoint along the forward model trajectory to identify

The North Atlantic Current (NAC) supplies the subpolar gyre with warm and saline water from the subtropics as part of the upper branch of the Atlantic Meridional Overturning Circulation (AMOC). In the context of climate changes, the North Atlantic Ocean is one of the key regions to investigate the variability of the overturning circulation in which salinity and freshwater variability are playing a

The land‐sea breeze is resonant with the inertial response of the ocean at the critical latitude of 30°N/S. 1‐D vertical numerical experiments were undertaken to study the key drivers of enhanced diapycnal mixing in coastal upwelling systems driven by diurnal‐inertial resonance near the critical latitude. The effect of the land boundary was implicitly included in the model through the “Craig approximation”

Wave‐supported fluid mud (WSFM) plays an important role in sediment downslope transport on the continental shelves. In this study, we incorporated WSFM processes in the wave boundary layer (WBL) into the Community Sediment Transport Modeling System (CSTMS) on the platform of the Coupled Ocean‐Atmosphere‐Wave‐and‐Sediment Transport modeling system (COAWST). The WSFM module was introduced between the

This study builds on Huntley and Ryan (2018) and related prior works on channels and estuaries by considering solutions for the same subtidal dynamics but with alternative integral flow constraints. Prior solutions do not have a truly two‐dimensional (2D) flow field, as axial changes in the axial flow are implied. Three constraint types are considered: the Constant case with spatially constant density

The transport of warm Atlantic Waters north of Svalbard is one of the major heat and salt sources to the Arctic Ocean. The circulation pathways and the associated heat transport influence the variability in the Arctic sea ice extent, the onset of freezing, and marine ecosystems. We present observations obtained from research cruises and an autonomous underwater glider mission in summer and fall 2018

The rate of ocean heat uptake depends on the mechanisms that transport heat between the surface and the ocean interior. A recent study found that the vertical heat transport driven by motions with scales smaller than 0.5° (submesoscales) and frequencies smaller than 1 day−1 is upward. This transport competes with the other major components of the global heat transport, namely, the downward heat transport

The northeast periphery of the Scotia Sea hosts one of the largest chlorophyll‐a blooms of the Southern Ocean. This bloom peaks to the northwest of the island of South Georgia, extending eastward for hundreds of kilometers. Although the Southern Ocean has many islands of similar size, South Georgia is ecologically one of the most significant: It not only sustains one of the Southern Ocean's largest

The Gulf of Mexico receives considerable riverine nutrient inputs that contribute to eutrophication of northern shelf waters. However, it is unclear whether a significant fraction of these riverine nutrients delivered to the Gulf of Mexico are subsequently exported from the Gulf, potentially influencing the chemistry of the North Atlantic. Here, we report the first dual isotopic composition (“δ15N”

The role of the internal tide in driving tracer transport across the continental slope is examined using simplified layered theory, channel model experiments and observational diagnostics of near shelf‐edge moorings. The effect of the internal tide is interpreted in terms of its Stokes' drift, which is separated into two distinct components: a bolus component, driven by the co‐variance of layer thickness

Sea‐ice thickness is a critical variable, both as a climate indicator and for forecasting sea ice conditions on seasonal and longer time scales. The lack of snow depth and density information is a major source of uncertainty in current thickness retrievals from laser and radar altimetry. In response to this data gap, a new Lagrangian snow‐evolution model (SnowModel‐LG) was developed to simulate snow

Extreme sea level variability (excluding the effects of mean sea level (MSL) and long‐period tidal cycles) at decadal to multidecadal time scales is significant along the U.S. coastlines and can modulate coastal flood risk in addition to long‐term MSL rise. Therefore, understanding the climatic drivers and ultimately predicting these low‐frequency variations are important. Extreme sea level indicators

The Madden‐Julian Oscillation (MJO) is the dominant mode of air‐sea interaction over intraseasonal timescales. The effects of the MJO are well understood, but the initiation of the MJO remains less conclusive, particularly under El Niño Southern Oscillation (ENSO) conditions. Primary MJO events are those not immediately preceded by existing MJO activity of sufficient strength. As they are rare by definition

The decadal to multidecadal temperature variability of the intermediate (700–2,000 m) North Atlantic Subpolar Gyre (SPG) significantly imprints the global pattern of ocean heat uptake. Here, the origins and dominant pathways of this variability are investigated with an ocean analysis product (EN4), an ocean state estimate (ECCOv4), and idealized modeling approaches. Sustained increases and decreases

Atlantic Water takes various pathways through the Nordic Seas, and its transformation to denser waters forms a crucial connection to the lower limb of the Atlantic Meridional Overturning Circulation. Circulation maps often schematize two distinct pathways of Atlantic Water: one following the Norwegian Atlantic Slope Current along the continental slope of Norway and one following the Norwegian Atlantic

A new method for generating synthetic salinity (SS) profiles in the Southwest Atlantic was developed and applied in data assimilation experiments. This method was based on the smallest integrated values of root mean square deviation (RMSD)—with respect to observations—to infer salinity through climatological data and by regressive methods on temperature (T) using a five‐order polynomial function (P5)

Variability in the El Niño‐Southern Oscillation (ENSO) has global impacts on seasonal temperatures and rainfall. Current detection methods for extreme phases, which occur with irregular periodicity, rely upon sea surface temperature anomalies within a strictly defined geographic region of the Pacific Ocean. However, under changing climate conditions and ocean warming, these historically motivated indicators

In order to document relative changes in water mass contributions in the Gulf of Maine (GoM), we used the shell material of the long‐lived ocean quahog (Arctica islandica). A multi‐century, crossdated master shell growth chronology facilitated the reconstruction of a radiocarbon Δ14C history prior to the radiocarbon bomb‐pulse of the 1950s. This reconstruction reveals a highly variable Δ14C series

Ocean reanalysis products are routinely employed as reality checks in model evaluations and for process studies. This is especially so for critical regions such as the equatorial cold tongue (ECT) in the eastern equatorial Pacific where models suffer a chronic cold bias. ECT is a major player in the Pacific equatorial zonal sea surface temperature (SST) gradient (ΔEWSST) that has a significant impact

At the base of the marine food web, phytoplankton are an essential component of the Arctic Ocean ecosystem and carbon cycle. Especially after sea ice retreats and light becomes more available to the Arctic Ocean each summer, phytoplankton productivity is limited by nutrient availability, which can be replenished by vertical mixing of the water column. One potential mixing mechanism is gale‐force wind

Melt ponds occupy a large fraction of the Arctic sea ice surface during spring and summer. The fraction and distribution of melt ponds have considerable impacts on Arctic climate and ecosystem by reducing the albedo. There is an urgency to obtain improved accuracy and a wider coverage of melt pond fraction (MPF) data for studying these processes. MPF information has generally been acquired from optical

No abstract is available for this article.

Our ability to predict the future of Arctic sea ice is limited by ice's sensitivity to detailed surface conditions such as the distribution of snow and melt ponds. Snow on top of the ice decreases ice's thermal conductivity, increases its reflectivity (albedo), and provides a source of meltwater for melt ponds during summer that decrease the ice's albedo. In this paper, we develop a simple model of

The Amundsen Sea has the highest thinning rates of ice shelves in Antarctica. This imbalance is caused by changes in ocean melting induced by warm Circumpolar Deep Water (CDW) intrusions. The resulting changing freshwater balance could affect the on‐shelf currents and mixing. However, a clear understanding of the sources and sinks of fresh water in the region is lacking. Here we use a model of the

Astronomical variations in tidal magnitude can strongly modulate the severity of coastal flooding on daily, monthly, and interannual timescales. Here, we present a new quasi‐nonstationary skew surge joint probability method (qn‐SSJPM) that estimates interannual fluctuations in flood hazard caused by the 18.6 and quasi 4.4‐year modulations of tides. We demonstrate that qn‐SSJPM‐derived storm tide frequency

Offshore real‐time ocean bottom networks of seismometers and ocean bottom pressure (OBP) gauges have been recently established such as DONET and S‐net around the Japanese islands. One of their purposes is to practice rapid and accurate tsunami forecasting. Near‐fault OBP records, however, are always contaminated by nontsunami components such as sea‐bottom acceleration change until an earthquake stops

Oceanic quantities of interest (QoIs), for example, ocean heat content or transports, are often inaccessible to direct observation, due to the high cost of instrument deployment and logistical challenges. Therefore, oceanographers seek proxies for undersampled or unobserved QoIs. Conventionally, proxy potential is assessed via statistical correlations, which measure covariability without establishing

Using SODA oceanic reanalysis data, the subduction rate and low potential vorticity (PV) water masses in the North Pacific are investigated from January 1870 to December 2008. A new low PV water mass with a large subduction rate is found near‐equatorial North Pacific, which is named as the near‐equatorial North Pacific low PV water mass (NELPVW), and it is the only one low PV water mass in North Pacific

Recent observations suggest that substantial phytoplankton blooms occur under sea ice on Arctic continental shelves during June and July. This is opposed to the traditional view that no significant biomass is produced in sea‐ice covered waters. However, no observational estimates are available on the Arctic‐wide primary production beneath sea ice. Here, using a fully coupled Arctic system model, we

A well‐defined Triple MOde of Salinity (TMOS) variability in the tropical Pacific thermocline layer (24–25.5 σθ isopycnal surfaces) is revealed from the Argo observations during 2004–2018. Thermocline salinity in the tropical northern and southwestern Pacific Ocean varies out of phase on interannual to near‐decadal time scales with that in the tropical southeastern Pacific Ocean. The TMOS is attributed

Numerical simulations of three of the most severe historical tropical cyclones to affect the Delaware River Basin (DRB) are used to evaluate a new numerical approach that is a candidate model for the inland‐coastal compound flood forecast. This study includes simulating interactions of tides/surges, freshwater streamflows, winds, and atmospheric pressure for the DRB. One‐way coupling between the hydrologic

No abstract is available for this article.

Given that few drifter experiments combined with a wave‐current coupled model system had been conducted in the complex nearshore area, this work was motivated to reveal the nearshore dynamics by applying an observation‐modeling system to Lake Michigan. Analysis of 11 surface drifters, wind, and current observations along the lake's eastern coast indicates that their trajectories are synergistically

Arctic and Antarctic sea ice has undergone significant and rapid change with the changing climate. Here, we present preindustrial and historical results from the newly released Community Earth System Model Version 2 (CESM2) to assess the Arctic and Antarctic sea ice. Two configurations of the CESM2 are available that differ only in their atmospheric model top and the inclusion of comprehensive atmospheric