E. Joseph Metzger

United States Naval Research Laboratory | NRL · Ocean Dynamics and Prediction Branch

Luzon Strait and the northern South China Sea are regions of high mesoscale eddy activity. These transient eddies are important to the local circulation and for water mass transports. This work applies satellite altimeter observations and an ocean model reanalysis, simulation, and forecasts to evaluate the realism of these eddies and to determine t...

During polar nights of 2012 and 2017, bioluminescence (BL) potential surveys demonstrated high emissions at depths around and below 100 m at offshore stations to the north of a Svalbard fjord (Rijpfjorden). We demonstrated that the highest bioluminescent emissions for offshore stations are located at depths below depths of modelled/ambient light in...

An empirical method is developed to predict the counter-wind South China Sea Warm Current (SCSWC) using wind stress at a specific location that is built on the most dominant Empirical Orthogonal Function (EOF) mode of the Sea Surface Height (SSH), i.e. the Ekman mode (Yu et al., 2021). Based on the most dominant EOF modes from a 22-year HYbrid Coor...

During polar nights in January 2012 and 2017, significantly higher bioluminescence (BL) potential emissions in the upper 50 m were observed in the fjord Rijpfjorden (Svalbard, Norway) in comparison to offshore stations (located on the shelf-break, shelf-slope areas and in the deeper water). The objective of this paper is to better understand why, d...

Intraseasonal variability (20-90 days) of the Indonesian Throughflow (ITF), which is primarily forced by the Madden-Julian Oscillation (MJO), is investigated using a high-resolution global ocean reanalysis and satellite altimeter data. Previous studies show that during the MJO active phase, downwelling Kelvin waves generated in the central equatori...

A 22-year (1994–2015) HYbrid Coordinate Ocean Model (HYCOM) global reanalysis is used to study the generation mechanism of the counter-wind characteristic of the South China Sea Warm Current (SCSWC) in winter seasons. Our analysis clearly demonstrates that the counter-wind SCSWC in winter is driven by wind relaxation. An Extended Empirical Orthogon...

Mesoscale eddies dominate energetics of the ocean, modify mass, heat and freshwater transport and primary production in the upper ocean. However, the forecast skill horizon for ocean mesoscales in current operational models is shorter than 10 days: eddy-resolving ocean models, with horizontal resolution finer than 10 km in mid-latitudes, represent...

The circulation in the northern South China Sea (SCS) strongly responds to anticyclonic eddies that shed from the Kuroshio intruding across Luzon Strait. An eddy tracking algorithm was applied to 26 years of altimetry data to better quantify the surface characteristics of eddies in and near the Luzon Strait with an emphasis on eddies with significa...

This paper describes the new global Navy Earth System Prediction Capability (Navy‐ESPC) coupled atmosphere‐ocean‐sea ice prediction system developed at the Naval Research Laboratory (NRL) for operational forecasting for timescales of days to the subseasonal. Two configurations of the system are validated: (1) a low‐resolution 16‐member ensemble sys...

Twin 5-month seasonal forecast experiments are performed to predict the September 2018 mean and minimum ice extent using the fully coupled Navy Earth System Prediction Capability (ESPC). In the control run, ensemble forecasts are initialized from the operational US Navy Global Ocean Forecasting System (GOFS) 3.1 but do not assimilate ice thickness...

Bioluminescence (BL) potential observations registered high BL potential emissions during the polar night of January 2012 at the mouth of a fjord Rijpfjorden (northern Svalbard, Norway). Notably, observations of BL potential at this location were significantly higher in the upper 50 m than observed BL potential at offshore stations located on the s...

Plain Language Summary Cyclones (storms) over the Arctic Ocean may be associated with periods of locally enhanced sea ice loss during the summer, and some studies have found that an intense cyclone in August 2012 resulted in a rapid sea ice retreat. This study uses a computer model (Navy‐ESPC) that includes interactions between the atmosphere, the...

There is a growing need for operational oceanographic predictions in both the Arctic and Antarctic polar regions. In the former, this is driven by a declining ice cover accompanied by an increase in maritime traffic and exploitation of marine resources. Oceanographic predictions in the Antarctic are also important, both to support Antarctic operati...

The Subseasonal Experiment (SubX) is a multimodel subseasonal prediction experiment designed around operational requirements with the goal of improving subseasonal forecasts. Seven global models have produced 17 years of retrospective (re)forecasts and more than a year of weekly real-time forecasts. The reforecasts and forecasts are archived at the...

The temporal variability of volume transport from the North Pacific Ocean to the East China Sea (ECS) through the Kerama Gap (between Okinawa Island and Miyakojima Island—a part of Ryukyu Island Arc) is investigated using a 20-year global HYbrid Coordinate Ocean Model reanalysis with the Navy Coupled Ocean Data Assimilation from 1993 to 2012. We st...

A pair of 12.5-year (July 2002-December 2014) HYbrid Coordinate Ocean Model (HYCOM) simulations that only differ in the wind stress formulation are used to investigate the effect of ocean surface currents on global monthly Eddy Kinetic Energy (EKE) variation. The model results (2004-2014) show that the global monthly mean EKE is reduced by 37%, fro...

Atmospheric rivers (ARs) cause heavy precipitation and flooding in the coastal areas of many mid-latitude continents, and thus the atmospheric processes associated with the AR have been intensively studied in recent years. However, AR-associated ocean variability and air-sea fluxes have received little attention because of the lack of high-resoluti...

https://deepblue.lib.umich.edu/bitstream/2027.42/146536/1/bookchapter_2018_arbicetal.pdf

A 17-year (1999–2015) HYbrid Coordinate Ocean Model (HYCOM) reanalysis is used to calculate the wind work to the global oceanic circulation with a focus on the global integral of the wind work on the ageostrophic currents. While the wind work on the geostrophic currents estimate of the study is in good agreement with previous research, our estimati...

In this study, the contribution of low-frequency ( > 100 days), Madden-Julian oscillation (MJO), and convectively coupled equatorial wave (CCEW) variability to the skill in predicting convection and winds in the tropics at weeks 1-3 is examined. We use subseasonal forecasts from the Navy Earth System Model (NESM); NCEP Climate Forecast System, vers...

We present here a study of the air-sea heat fluxes for the global ocean during fall 2015 within the Earth System Prediction Capability (ESPC) project. In particular, we compared the ESPC-derived heat fluxes with fields derived by the Naval Research Laboratory Ocean Surface Flux (NFLUX) System, and the Modern Era Retrospective-Analysis for Research...

The existence of a seasonally varying undercurrent along 8° N off the east coast of Sri Lanka is inferred from shipboard hydrography, Argo floats, glider measurements, and two ocean general circulation model simulations. Together, they reveal an undercurrent below 100–200 m flowing in the opposite direction to the surface current, which is most pro...

A more complete wind stress (τn) formulation takes into account the ocean surface currents (Vo), while the conventional wind stress (τc) popularly used in ocean circulation models is only a function of 10-m winds (V10). An analytical solution is derived for the difference of Sverdrup transport induced by using τn instead of τc. A scaling analysis o...

Previous studies indicate that equatorial zonal winds in the Indian Ocean can significantly influence the Indonesian Throughflow (ITF). During the Cooperative Indian Ocean Experiment on Intraseasonal Variability (CINDY)/Dynamics of the Madden-Julian Oscillation (DYNAMO) field campaign, two strong MJO events were observed within a month without a cl...

Ocean analyses and forecasts from operational prediction systems are known to contain errors from a variety of sources. Some of those sources are introduced by errors in the surface boundary conditions, i.e. the wind and heat flux forcing. These errors in turn introduce errors, or biases, in the corresponding ocean forecasts. We have forced a high...

The structure and variability of the Ryukyu Current System (RCS), which forms the western boundary current along the eastern slope of the Ryukyu Islands, are studied using results from a 32-layer, 1/12.5° global HYbrid Coordinate Ocean Model (HYCOM) and Navy Coupled Ocean Data Assimilation (NCODA) reanalysis for the period 1993-2012. It is confirme...

The temporal variability of volume transport from the North Pacific Ocean to the East China Sea (ECS) through Kerama Gap (between Okinawa Island and Miyakojima Island - a part of Ryukyu Islands Arc) is investigated using a 20-year global HYbrid Coordinate Ocean Model (HYCOM) reanalysis with the Navy Coupled Ocean Data Assimilation from 1993 to 2012...

In this study the forecast skill of the U.S. Navy operational Arctic sea ice forecast system, the Arctic Cap Nowcast/Forecast System (ACNFS), is presented for the period February 2014 to June 2015. ACNFS is designed to provide short term, 1-7 day forecasts of Arctic sea ice and ocean conditions. Many quantities are forecast by ACNFS; the most commo...

Shipboard velocity and hydrographic profiles collected in December 2013 along with drifter observations, satellite altimetry, global ocean nowcast/forecast products, and coupled model simulations were used to examine the circulation in the southern Bay of Bengal as part of ongoing international research efforts in the region. The observations captu...

This study presents the improvement in ice edge error within the US Navy's operational sea ice forecast systems gained by assimilating high horizontal resolution satellite-derived ice concentration products. Since the late 1980's, the ice forecast systems have assimilated near real-time sea ice concentration derived from the Defense Meteorological...

This study presents the improvement in the US Navy's operational sea ice forecast systems gained by assimilating high horizontal resolution satellite-derived ice concentration products. Since the late 1980's, the ice forecast systems have assimilated near real-time sea ice concentration derived from the Defense Meteorological Satellite Program (DMS...

The Naval Oceanographic Office (NAVOCEANO) provides daily operational global, regional, and coastal ocean model forecasts and their associated prediction products. The models utilized include three-dimensional circulation, wave, and ice forecasting systems that have been developed to meet Navy requirements; the models are forced by Navy atmospheric...

The US Navy's operational global ocean nowcast/forecast system is presently comprised of the 0.08° HYbrid Coordinate Ocean Model (HYCOM) and the Navy Coupled Ocean Data Assimilation (NCODA). Its high horizontal resolution and adaptive vertical coordinate system make it capable of producing nowcasts (current state) and forecasts of oceanic "weather,...

Results from two 1/12° eddy-resolving simulations, together with data-based transport estimates at 26.5°N and 41°N, are used to investigate the temporal variability of the Atlantic meridional overturning circulation (AMOC) during 2004-2012. There is a good agreement between the model and the observation for all components of the AMOC at 26.5°N, whe...

The impact of parameterized topographic internal lee wave drag on the input and output terms in the total mechanical energy budget of a hybrid coordinate high-resolution global ocean general circulation model forced by winds and air-sea buoyancy fluxes is examined here. Wave drag, which parameterizes the generation of internal lee waves arising fro...

[1] We apply several skill tests to assess tidal currents within a three-dimensional, eddy resolving, global ocean circulation model compared to over 5000 observational velocity records spanning 40 years. We examine the skill of the HYbrid Coordinate Ocean Model (HYCOM) on a regional, basin, and global scale and in deep versus shallow water. On a g...

Multiple international agencies have performed atmospheric reanalyses using static dynamical models and assimilation schemes while ingesting all available quality controlled observational data. Some are clearly aimed at climate time scales while others focus on the more recent time period in which assimilated satellite data are used to constrain th...

This paper describes present and planned capabilities for regional and global scale air-ocean-wave-ice forecasting systems using the Navy's Coupled Ocean Data Assimilation (NCODA) system. The Naval Research Laboratory Oceanography Division has transitioned the Arctic Cap Nowcast/Forecast System (ACNFS) to operations at the Naval Oceanographic Offic...

The slopes of the wavenumber spectra of sea surface height (SSH) and kinetic energy (KE) have been used to infer "interior" or surface quasi-geostrophic (QG or SQG) dynamics of the ocean. However, inspection of spectral slopes for altimeter SSH in the mesoscale band of 70 to 250 km shows much flatter slopes than the QG or SQG predictions over most...

Global comparisons of barotropic and internal tides generated in an eddy-resolving ocean circulation model are made with tidal estimates obtained from altimetric sea surface heights and an altimetry-constrained tide model. As far as we know, our Hybrid Coordinate Ocean Model (HYCOM) simulations shown here and in an earlier paper are the only publis...

We present and apply several skill tests to assess tidal currents generated within a global ocean model compared to an archive of current meter records spanning 40 years. Within the North Atlantic we have identified over 1800 velocity records available for comparison to model output. The skill tests identify those regions where tidal ellipse parame...

We compared the estimates of surface drifter trajectories from 1 to 7 days in the equatorial Atlantic over an 18-month period with five eddying ocean general circulation model (OGCM) reanalyses and one observational product. The cumulative distribution of trajectory error was estimated using over 7,000 days of drifter trajectories. The observationa...

In 2008-2009 the Makassar throughflow profile changed dramatically: the characteristic thermocline velocity maximum increased from 0.7 to 0.9 m/sec and shifted from 140 m to 70 m, amounting to a 47% increase in the transport of warmer water between 50 and 150 m during the boreal summer. HYCOM output indicates that ENSO induced change of the South C...

Ocean tides, and the atmospherically forced oceanic generalcirculation and its associated mesoscale eddy field, have long been run separately in high-resolution global models. They are now being simulated concurrently in a high-resolution version of the HYbrid Coordinate Ocean Model (HYCOM). The incorporation of horizontally varying stratification...

The Naval Research Laboratory has developed a two-way coupled Arctic Cap Nowcast Forecast System (ACNFS) which consists of the Los Alamos Community Ice Code (CICE), the Hybrid Coordinate Ocean Model (HYCOM) and the Navy Coupled Ocean Data Assimilation (NCODA) system. Model fields are exchanged using the Earth System Modeling Framework (ESMF). The A...

The characteristics and plausible genesis of the 20–40 day variability observed within the Labani Channel, a constriction within the Makassar Strait, Indonesia, are described. The 20–40 day variability, trapped beneath the depth of the strongest stratification of the pycnocline, is most evident in the across-strait flow, and in the across-strait gr...

The U.S. Navy Arctic Cap Nowcast/Forecast System (ACNFS) is designed to provide short term (order 5 day) forecasts of Arctic ocean/ice conditions. Like many short term weather forecast system, ACNFS uses data assimilation to improve forecasts based on current observations. Regarding observations and model forecasts, the quicker the data is availabl...

El Niño Modoki is a variant of El Niño characterized by warming around the dateline flanked by anomalous cooling in the east and west. However, the opposite phase (La Niña Modoki) has received little attention because the prominent cooling of sea surface temperature (SST) during major La Niña events is observed in the central Pacific, and thus, it...

The ocean west of the main Hawaiian Islands is characterized by enhanced eddy kinetic energy arising from the abundance of locally generated mesoscale eddies, most frequently in the area west of the island of Hawaii. Two mechanisms of eddy generation in the wake of an island are examined with numerical model experiments. The first, eddy generation...

Over the last decade, ice conditions in the Arctic have changed dramatically resulting in the Arctic having a minimum in ice extent during the summers of 2007, 2008 and 2010. With this rapidly changing polar environment, the need for accurate ice forecasts is essential. The Naval Research Laboratory (NRL) has developed the Arctic Cap Nowcast/Foreca...

Three ocean models, 1/25 degrees global HYbrid Coordinate Ocean Model (HYCOM), 1/12 degrees global HYCOM, and East Asian Seas Navy Coastal Ocean Model (EAS NCOM) nested in global NCOM, were used to provide a global context for simulation of the circulation within the Philippine Archipelago as part of the Philippine Straits Dynamics Experiment (Phil...

Three ocean models, 1/25° global HYbrid Coordinate Ocean Model (HYCOM), 1/12° global HYCOM, and EAS NCOM nested in global NCOM, were used to provide a global context for simulation of the circulation within the Philippine Archipelago as part of the Philippines Experiment (PhilEx). The Philippine Archipelago provides two significant secondary routes...

The 7 years (2003-2009) of output from a regional version of the Hybrid Coordinate Ocean Model (HYCOM) nested in global HYCOM are used to study the seasonal and interannual variability of the salinity in the northern Gulf of California (NGOC). Previous studies illustrate that the NGOC is characterized by an annual evaporation of ~0.9 m/yr. This eva...

Over the last decade, ice conditions in the Arctic have changed dramatically resulting in the Arctic having a minimum in ice extent during the summers of 2007, 2008 and 2010. With this rapidly changing polar environment, the need for accurate ice forecasts is essential. The Naval Research Laboratory (NRL) has developed the Arctic Cap Nowcast/Foreca...

The HYbrid Coordinate Ocean Model (HYCOM) has been configured for the Gulf of California (GOC) at 1/12° and 1/25° horizontal grid resolution and has been nested inside a basin-scale 1/12° Pacific version of HYCOM. The nested GOC models are used to study the upper-ocean GOC response to Hurricane Juliette. The model results indicate that Juliette’s w...

This paper presents a five-year global simulation of HYCOM, the HYbrid Coordinate Ocean Model, that simultaneously resolves the eddying general circulation, barotropic tides, and baroclinic tides with 32 layers in the vertical direction and 1/12.5° (equatorial) horizontal grid spacing. A parameterized topographic wave drag is inserted into the mode...

The seasonal variation of Indonesian Throghuflow (ITF) transport is investigated using a series of ocean general circulation model experiments with the HYbrid Coordinate Ocean Model (HYCOM). The Indo-Pacific basin (55°N-55°S) HYCOM (1/3° horizontal resolution) was integrated for the period 1950-2008 with surface forcing fields based on the ERA 40,...

This report documents the ocean model response of adding diurnal variations to the incoming shortwave radiation forcing applied to the Global Ocean Forecast System Version 3.0. This can have a large impact on near surface ocean temperature and mixed layer, especially in low wind conditions when the near surface ocean is strongly stratified. This so...

Naval Research Laboratory has compared sea ice hindcast for the Arctic Ocean derived from the latest coupled ice-ocean prediction system to observations. The system is based on the HYbrid Coordinate Ocean Model coupled via the Earth System Modeling Framework to the Los Alamos Community Ice CodE and tested using the Navy Coupled Ocean Data Assimilat...

A 1/12° global version of the HYbrid Coordinate Ocean Model (HYCOM) using 3-hourly atmospheric forcing is analyzed and directly compared against observations from the International Nusantara STratification ANd Transport (INSTANT) program that provides the first long-term (2004–2006) comprehensive view of the Indonesian Throughflow (ITF) inflow/outf...

A fine resolution (≈3.3km) version of the HYbrid Coordinate Ocean Model (HYCOM) is developed for the Caspian Sea. The model consists of a hybrid σ–z coordinate system, with σ-coordinates for the upper layers and z-levels below a user-specified depth and in very shallow water. General features of the Caspian Sea HYCOM are presented including the bot...

In this paper, we study, in detail, one important aspect of our ongoing work on global ocean prediction. Modeling the behavior of western boundary currents, like the Gulf Stream, has been a long-standing issue. Recent modeling results suggest that the abyssal currents play an important role in determining the pathway of the Gulf Stream. The present...

The 1/12 degree global HYbrid Coordinate Ocean Model (HYCOM) has been running daily since 22 December 2006. With ~7 km mid-latitude resolution (3-4 km near the poles), the system depicts the location of mesoscale features such as oceanic eddies and fronts and provides the three dimensional ocean temperature, salinity and current structure. An effic...