An official website of the United States government
Here's how you know
A .mil website belongs to an official U.S. Department of Defense organization in the United States.
A lock (lock ) or https:// means you’ve safely connected to the .mil website. Share sensitive information only on official, secure websites.

sky background image

Naval Oceanography: Pathfinders of the American Military – Part 1

09 January 2023

From Ed Darack -Wetherwise Magazine

The modern U.S. Navy operates some of the most technologically advanced systems ever created. These include much heralded programs such as the USS Gerald R. Ford (CVN 78) aircraft carrier, the F-35C Lightning II fifth-generation multirole combat jet, and Virginia-class attack submarines. Icons of national power and the culmination of decades of innovation, rigorous testing, and trials by fire, these and other key American military assets can only function to their full capabilities with the backing of myriad support elements. One of the most important of these is the Naval Meteorology and Oceanography Command, COMNAVMETOCCOM, typically shortened to METOC, pronounced “me-tock.” It is referenced throughout the Navy and the Department of Defense by its umbrella term “Naval Oceanography.” The command, headquartered at NASA’s John C. Stennis Space Center in Mississippi . . .
Copyright 2023 by Ed Darack ; Originally published in Weatherwise Magazine, issue 1, Volume 76: January – February 2023.
Permission granted by Ed Darack to the United States Navy for Publication in Electronic and Physical Form


The modern U.S. Navy operates some of the most technologically advanced systems ever created. These include much heralded programs such as the USS Gerald R. Ford (CVN 78) aircraft carrier, the F-35C Lightning II fifth-generation multirole combat jet, and Virginia-class attack submarines. Icons of national power and the culmination of decades of innovation, rigorous testing, and trials by fire, these and other key American military assets can only function to their full capabilities with the backing of myriad support elements. One of the most important of these is the Naval Meteorology and Oceanography Command, COMNAVMETOCCOM, typically shortened to METOC, pronounced “me-tock.” It is referenced
throughout the Navy and the Department of Defense by its umbrella term “Naval Oceanography.”
The command, headquartered at NASA’s John C. Stennis Space Center in Mississippi just inland of the Gulf of Mexico, began humbly as a small navigation implement repository and maintenance facility in Washington D.C. Through the decades, as the U.S. military has expanded its range of capabilities, Naval Oceanography has become the Department of Defense’s premier environmental situational awareness provider. It produces a wide range of meteorological, oceanographic, and navigational products, directly supporting Navy and U.S. military conventional and special operations missions, globally. From a technical military standpoint, the best way to describe METOC’s overarching function is that it “optimizes environmental situational awareness in all physical warfighting
domains at the tactical, operational, and the strategic levels for the country’s warfighters and those of its allies.” Optimizing environmental situational awareness means providing the most accurate, timely, and relevant information about dynamic physical surroundings of friendly forces to a degree greater than that which any adversary could possibly attain. Physical warfighting domains are land, sea, air, and space. Conceptual warfighting levels range from the tactical (smallest), to the most expansive, the strategic. Tactical engagements and actions can occur in an area as small as a half-acre (or even smaller). Operational represents the aggregate of the tactical, and is typically as physically expansive as a few miles to a few tens of miles. Strategic describes national-level actions and outcomes that typically have historic implications—like a nuclear strike, launched from a U.S. Navy Ohio Class ballistic missile submarine. METOC plays critical roles throughout this warfighting spectrum on a constant basis, whether at war or not. Its state-of-the-art systems, processes, and above all, highly specialized personnel, have built this command into what is arguably the most advanced atmospheric and oceanographic systems dynamics entity in history. National defense not only relies on this level of capability, it demands it. “Naval Oceanography operates simultaneously at the strategic, operational and tactical levels of warfare in every theater around the globe,” explained Rear Admiral Ron Piret, commander of Naval Oceanography and the Oceanographer and Navigator of the U.S. Navy. “We pride ourselves in our ability to characterize the battle space and then predict changes in the environment over time.”
History provides countless examples where knowledge of the environment has provided a critical advantage over an enemy—and where oversight of such details has led to disaster. Furthermore, some of Naval Oceanography’s information supports not just the U.S. military, but a tremendous range of vital private and commercial activities throughout the globe, activities that would grind to a halt without METOC’s continuous support.
Naval Meteorology, A History
The history of the Naval Meteorology and Oceanography Command stretches back nearly two centuries. On December 6, 1830, then Secretary of the Navy, John Branch, directed 25-year-old Navy Lieutenant Louis M. Goldsborough to establish a facility to maintain, update, and log performance data for all of the Navy’s navigation equipment. This included chronometers, necessary for mariners to compute longitude. Established on a budget of $330 (plus his salary), Goldsborough opened the Depot of Charts and Instruments in early 1831 in Washington D.C., near the White House (see Sidebar 1 on the modern iteration of this command, the U.S. Naval Observatory). The overarching goal of the depot was to ensure that the Navy would always maintain the highest degree of precision in navigation on the high seas as was possible, the most basic form of environmental situational awareness. The Depot worked to give Navy personnel the best tools and information for this end, with an emphasis on calibrating their chronometers. Shortly after opening the depot, the Navy recognized the need for a detailed understanding and observation of celestial bodies, integral to gauging both time and position. In 1834, under the directorship of Navy Lieutenant Charles Wilkes, the Depot moved to a location just north of the Capitol, a part of Washington, D.C., much better situated for viewing the heavens. After expanding their repertoire with the inclusion of astronomy, the Depot undertook its first hydrographic survey. Led by Wilkes, members of the Depot explored Georges Bank, an elevated swath of seafloor of the North Atlantic Ocean east of Cape Cod, Massachusetts.
In November of 1838, just after the Georges Bank survey, the Depot began regimented meteorological observations. Working under a broad directive of the Secretary of the Navy that mandated an ever greater degree of environmental understanding, then officer in charge of the Depot, Lieutenant James Melville Gilliss, had the Depot take and record key atmospheric data. These included weather type (clear, rain, cloudy); wind force (calm, light, moderate, heavy); wind direction; temperature, both in the sun and in the shade; dew point; atmospheric pressure; 24-hour precipitation; diurnal maximum and minimum temperatures; and evaporative potential. Depot personnel made these measurements four times per 24-hour period: 3 a.m., 9 a.m., 3 p.m., and 9 p.m. In less than a decade, the Naval Depot of Charts and Instruments established itself as an exploratory body of the sea, the stars, and the sky. In the years to come, this work would continue to accelerate in scope and breadth, due in great measure to the superintendent who took charge of the command in 1842, Navy Lieutenant Matthew Fontaine Maury. Born January 14, 1806, Maury was fascinated by the heavens, the world’s oceans, and the sky from a young age. At 19, he became a midshipman, a U.S. Naval officer in training, and served initially on the frigate USS Brandywine. As his naval career progressed, Maury both taught himself and pioneered the disciplines of meteorology, oceanography, astronomy, cartography, and geography. He focused on the interaction of winds, latitudes, and ocean currents, forging a synthesized view of the sky and the ocean. He was a member of a number of ship crews during his total of nine years at sea, including on the USS Vincennes when it made the first circumnavigation of the world by an American warship. He published a number of books, including On the Navigation of Cape Horn, Plan of an Instrument for Finding the True Lunar Distance, and A New Theoretical and Practical Treatise on Navigation. The latter, first scientific book written and published by a U.S. Naval officer, proved a tremendous success, with a copy placed on every ship in the Navy in 1837. His work made him famous, and he became known as the “Father of Modern Oceanography,” the “Father of Naval Meteorology,” and most enduringly, “Pathfinder of the Seas.”
After nearly a decade on the world’s oceans, his seafaring career came to an abrupt end in 1839. While travelling to the New York Naval Yard after a visit with his parents, the stagecoach on which he was a passenger overturned, breaking his right femur. The injury rendered him permanently unfit for sea duty. After a long recovery, he took the job of superintendent of the Depot of Charts and Instruments, reporting for duty on July 4, 1842. During his tenure at the command, Maury took what had been accomplished in the fields of meteorology, oceanography, and astronomy and combined it with his work and the outlook that he had forged while on the seas. Under his directorship, the Depot became the premier scientific institution in the country, pioneering the disciplines of hydrography and atmospheric science. Among Maury’s many accomplishments, the installation produced a series of influential navigation charts that revolutionized maritime travel for both the Navy and commercial shipping.
The decades that followed saw the Navy change the name of the command a number of times, move it to its current location, and enhance its capabilities through a number of the nation’s most grueling, and important, conflicts. With each war, and with each advancement in military, meteorological, astronomical, and oceanographic technology, the knowledge base grew. As the nature of warfare evolved—with the advent of air power, changes in sea power to include submarine warfare, and with the introduction of space systems—Navy meteorology, oceanography, and navigational capabilities expanded, adapted, and evolved, always maintaining a place at the edge of innovation, often pioneering it. The command has been responsible for a number of discoveries and important experiments, including discovering the moons of Mars and verifying the effects of Albert Einstein’s general and special theories of relativity. Maury’s tenure, which combined the foundational work of the Depot with his own outlook, burgeoned over the decades to form the modern Naval Meteorological and Oceanography Command. Today, rooted in the spirit of Maury, members of the command are the modern pathfinders of the Navy and the American military.
The Modern METOC
METOC today comprises fourteen subordinate commands and employs over 2,600 people, including members of the Navy (many with the official title of aerographer, who collect both meteorological and oceanographic data), full-time government employees, and contractors. They are located throughout the globe, and operate and source data from a wide range of systems, including unmanned underwater vehicles, manned surface vessels, aircraft, satellites, and deep space telescopes, engendering their motto “from the bottom of the ocean to the stars.” The products that Naval Oceanography produces support operations throughout the Department of Defense, both conventional and special operations—and because they are a component of the Navy, they have a special emphasis for operations organic to the service, including anti-submarine warfare, naval special warfare, fleet operations, and naval aviation, among others. The individual components of METOC include the U.S. Naval Observatory (the modern embodiment of METOC’s progenitor, the Naval Depot of Charts and Instruments), the Naval Ice Center, the Joint Typhoon Warning Center, two Fleet Weather Centers, the Naval Oceanographic Office, and the Fleet Numerical Meteorology and Oceanography Center.
Ranking among the most important of products Naval Oceanography delivers to the Navy and the Department of Defense are myriad environmental forecasts, and notably, weather forecasts. “Not a ship gets underway and not an aircraft takes off without a forecast from our community,” explained Captain Kate Hermsdorfer, the commanding officer of METOC’s Fleet Weather Center San Diego, which is responsible for providing forecasting for the geographic area stretching from the West Coast of the United States to the Suez Canal. This includes the entire Indo Pacific region, formally classified as the USINDOPACOM Geographic Combatant Command by the Department of Defense. METOC’s Fleet Weather Center Norfolk VA is responsible for the Atlantic and the Mediterranean regions. Hermsdorfer explained that some ships have embedded METOC personnel onboard, and some don’t. Either way, ships receive timely forecasts, custom tailored to their needs. Forecasts include a variety of relevant data, including wind speeds and directions, sea conditions, fronts, and expected precipitation and other conditions. While focused on maritime travel, METOC generates environmental forecasts for military personnel and platforms functioning in all physical warfighting domains: sea, land, air, and even for space-based platforms.
The forecasts are focused largely on safety of flight for aircraft and safety of navigation for surface vessels and submarines. To this end, Naval Oceanography personnel generating these products take into consideration a number of factors about the platforms that will be traversing regions for which the forecasts are to be made. These include dimensions of ships, including length, beam, and wave size that they can sustain. Even the latest aircraft carrier, the USS Gerald R. Ford (CVN 78), has its limits with respect to wave height. A poor forecast, or a forecast unheeded, can lead to a ship sinking. An example of this, unrelated to Naval Oceanography, occurred with the commercial cargo vessel SS El Faro, when it sank while in the eyewall of 2015’s category 3 Hurricane Joaquin. Waves that battered the vessel were estimated to have been upward of 30 feet. Routers, who are integral to METOC’s two Fleet Weather Centers in determining specific ship routes, work with individual Navy ships underway to ensure their safe passage based on predicted weather events.
Captain Hermsdorfer noted that their forecasts, in addition to ensuring safe passage and safe operation of platforms, are developed with operational efficacy in mind. “We look at operational intent,” she explained. Forecasts are then fashioned in as great of detail as necessary, including recommended routing. These can include tactical situations, in which a certain predicted weather event may provide leverage over a potential adversary, such as fog or high seas.
The U.S. Naval Observatory: Providing Precision Time and Location Data for the U.S. Department of Defense—and the Entire World
The U.S. Naval Observatory (USNO), the historic origin of METOC, today performs some of the American Military’s most technical, far-reaching, and critically-important work. While not directly involved in meteorological and oceanographic observation and prediction, the USNO provides precise time and location data, which is used not only by other components of METOC and the Navy, but by the entire Department of Defense—and the entire world.
The Observatory, founded in 1830 in Washington D.C. as the Naval Depot of Charts and Instruments, was established to ensure the proper function of all the Navy’s navigation equipment, notably chronometers. Accurately functioning chronometers were vital to maritime travel at that time as they are necessary to gauge longitude while at sea. Calibrating and gauging the reliability of each instrument was performed by comparing its function against the timing of the rotation of the earth. To do this, the observatory used a “transit telescope,” an optical system that precisely measures positions of celestial bodies, notably stars, as they visually intersect the meridian passing through the observatory’s location as the planet rotates.
From these beginnings, the small facility soon began disseminating time and celestial body information. In 1845, personnel at the Depot began dropping a large ball at noon every day, visible to citizens of Washington D.C. as well as to ships plying the Potomac River. In later years, Western Union transmitted USNO coordinated time throughout the United States. Starting in 1852, the Depot began publishing the “American Ephemeris and Nautical Almanac,” an annual publication giving precise positions of celestial bodies, necessary for maritime navigation and a number of terrestrial applications, like surveying. The information is still published each year, although it has been divided into two publications, the Nautical Almanac and the Astronomical Almanac, since 1981.
Today, the USNO continues to provide time and positioning information, and the instruments the facility uses—descendants of its earliest telescopes and chronometers—are the most advanced and precise in the world. The U.S. Naval Academy continues to teach celestial navigation, and the Navy considers it a backup form of navigation on ships. It is also a form of navigation on another type of Navy vehicle, a Trident II D5 submarine launched ballistic missile. Once launched, a special star tracking camera isolates a star in the sky and compares its location to digital tables the USNO produces, and then the missile makes adjustments to align itself onto the proper course to the target (such missiles do not use GPS as this system can possibly be jammed or “spoofed”). The science is called astrometry (related to astronomy). With astrometry, which the USNO continues to pioneer, specialists take extremely precise measurements of celestial bodies.
“USNO has two main jobs that can be summarized in two words: reference frames,” explains Geoff Chester, the public affairs officer of the USNO. Position information comes from radio telescopes, located throughout the globe, that observe quasars. Quasars, extremely bright galactic cores, are some of the most distant objects known in the universe. Although the universe is expanding, their great distances make them essentially stationary to an observer on earth, and provide ideal “fixed” positional references. “Perhaps the most important part of these measurements are called Earth Orientation Parameters (EOPs),” explains Chester, who has a background in astronomy and physics (and whose great grandfather was the superintendent of the observatory from 1902 to 1906). “When measured against the celestial reference frame, we can see the small but significant changes in the Earth’s speed of rotation as well as the changing angle of the planet’s rotational poles. These parameters figure into the position solutions of GPS.”
GPS, or Global Positioning System, relies on the USNO’s time calculations to function. The foundational process of GPS is called multilateration, in which precise distance measurements from each of three or more orbiting satellites to a position on the surface of the planet gives a precise coordinate for that position. With the speed of light known, distances are calculated by time-of-travel from each satellite to the position in question, hence the importance of precision time.
Called the Department of Defense Master Clock, the USNO system that coordinates this process is an ensemble of more than 100 specialized atomic clocks. Atomic clocks, initially developed by Britain’s National Physical Laboratory in the early 1950s, rely on counting oscillations of the single valence electron of certain atoms (cesium, rubidium, and hydrogen). Chester explains that when these atoms are stimulated by microwave radiation, the electron oscillates between two “hyperfine” states at a specific frequency. “Working with astronomers here at USNO, a relationship was determined that linked an astronomically defined second, the Ephemeris Second, with a specific frequency of oscillation in the cesium-133 atom. Since 1967, the second has been defined by this frequency as the duration of 9,192,631,770 cycles of radiation corresponding to the transition between two hyperfine levels of the ground state of cesium-133.” Clocks that use cesium, Chester explains, are formally called “cesium beam frequency standards,” as their frequency defines the second. Each GPS satellite has a number of onboard atomic clocks, some that use cesium and some that use rubidium. Just as the USNO originally analyzed chronometers and noted any deviations from locally-observed timing, personnel at the USNO today carefully check the onboard clocks on GPS satellites daily against the Master Clock, which has a precision of a few hundred picoseconds (a picosecond is a trillionth of a second). Any deviations in specific clocks in satellites from the Master Clock are disseminated so that receivers can automatically adjust and provide location information of the highest possible accuracy and precision. Department of Defense GPS satellites transmit frequencies usable by any GPS-enabled device on earth, and furthermore, USNO adjustments are disseminated globally. USNO-sourced timing data are critical in a number of nonmilitary applications. Virtually all global electronic financial transactions and computer and telephonic networking systems rely on the USNO’s continuously updated timing standards. Just like the early days when it provided daily noontime ball drops for residents of Washington D.C. and those on the Potomac, the modern USNO keeps the entire U.S. Military—and much of the entire world—synchronized.
Ed Darack is an author, unmanned systems developer, and founder of Darack Research. More information at

Copyright 2023 by Ed Darack ; Originally published in Weatherwise Magazine, issue 1, Volume 76: January – February 2023.
Permission granted by Ed Darack to the United States Navy for Publication in Electronic and Physical Form


Commander, Naval Meteorology and Oceanography Command | 1100 Balch Blvd. | Stennis Space Center, Mississippi 39529

Guidance-Card-Icon Dept-Exclusive-Card-Icon