Staff from the Center for Operational Oceanographic Products and Services install a microwave radar water level sensor on the Dog River Bridge in Mobile County, Ala. This is one of five stations installed to support the County's storm surge monitoring network established in 2011.

There are 21 Physical Oceanographic Real-Time Systems (PORTS®) located around the U.S. with the goal of supporting safe and efficient marine transportation.

On June 20, 2012, the M/V Zhen Hua 13 delivered new cranes from China to the Port of Baltimore by navigating the waters of Chesapeake Bay. To reach this destination, the cranes had to clear a major obstacle—passing under the Chesapeake Bay Bridge outside of Annapolis. As the cranes slid under the bridge, the National Ocean Service provided air gap information as part of the Northern Chesapeake Bay Physical Oceanographic Real-Time System (PORTS®). These measurements, along with real-time tides and current data, helped to ensure a safe and early passage of the ship in to the Port of Baltimore.

An iceberg captured on camera during a 30-day mission in 2012 to map areas of the Arctic aboard the NOAA Ship Fairweather.

As multi-year sea ice continues to disappear at a rapid rate, vessel traffic in the Arctic is on the rise. NOAA is working to update Arctic nautical charts, add new tide and current monitoring stations, and conduct geodetic surveys to support safe navigation, national security, and economic growth in the region.

The NOAA Ship Thomas Jefferson prepares to bring aboard one of its launches after a day of hydrographic surveying in Long Island Sound. In 2012, the Thomas Jefferson and its two launches are working in a collaborative effort with the states of Connecticut and New York, to gather data that will help guide policy decisions about future uses of the sea floor, as well as to update nautical charts.

The NOAA Ship Fairweather is named after Mt. Fairweather, located in Alaska's Glacier Bay National Park and Preserve along the U.S.-Canada border. Mt. Fairweather was named by Captain Cook in 1778, presumably because of the good weather encountered at the time of his visit. Fairweather conducted a 2012 reconnaissance mission to help NOAA prioritize its efforts to update navigational charts in the Arctic.

NOAA’s newest survey vessel is the Ferninand R. Hassler. Hassler is a state-of-the-art coastal mapping vessel designed to detect and monitor changes to the sea floor. Data collected by the ship will be used to update nautical charts, detect potential hazards to navigation, and further enhance our understanding of the ever-changing marine environment.

A view of the new "Gateway to NOAA," a permanent exhibit now open in Silver Spring, Maryland. The exhibit--only steps away from the Silver Spring Metro stop--features breathtaking imagery, multimedia presentations, and amazing artifacts that illustrate how NOAA has, since its earliest history, sought to increase people's understanding of the land, the sea, and the sky.

The Center for Operational Oceanographic Products and Services manages the National Water Level Observation Network (NWLON). NWLON provides basic water-level information to determine U.S. coastal marine boundaries and to create nautical charts. It also supports climate monitoring activities, tsunami and storm surge warning systems, coastal processes, and tectonic research. This NWLON station supports the Sabine-Neches, Texas, Physical Oceanographic Real-Time System.

The Center for Operational Oceanographic Products and Services manages the National Water Level Observation Network (NWLON). NWLON provides basic water-level information to determine U.S. coastal marine boundaries and to create nautical charts. On September 9, 2011, a new water level station on Lake Michigan in Holland, Michigan, was declared officially operational. The new station, a replacement for an older structure, was a joint upgrade effort by NOAA and the U.S. Army Corps of Engineers, Detroit District office. The new station is expected to provide modernized and highly-reliable water level data to the Great Lakes community for the next 50+ years.

If you filled out the 2010 Census form from the U.S. Census Bureau, then you had a part in defining the centroid -- the point where the center of the U.S. population falls. Every 10 years, after the Census Bureau crunches the numbers and figures out where the centroid is, NOAA's National Geodetic Survey places a geodetic survey disk (also called a survey marker, monument, or bench mark) in the incorporated community closest to its exact geographic location. For the 2010 Census, the centroid is located in Plato, Missouri.

NOAA's Office of Coast Survey worked with state and federal partners following the March 11, 2011 tsunami. Using a small boat equipped with powerful echo-sounding SONAR equipment, this navigation response team in Crescent City, Calif, searched the seafloor for sunken vessels, debris, and other hazards dangerous to commercial shippers and recreational boaters.

The March 11, 2011 tsunami off the coast of Japan left the port at Crescent City, Calif., in a shambles, with marine debris and wreckage above and below the waterline. To prepare the port for re-opening, a navigation response team from NOAA's Office of Coast Survey used their echo sounders to find underwater debris.

NOAA's Office of Coast Survey responded to requests from the Coast Guard and the Army Corp of Engineers following the March 11, 2011 tsunami. A navigation response team surveyed the federal channel at the port in Santa Cruz, Calif., which experienced extensive damage and destruction to boats, looking for submerged debris. The bathymetric data will also be used to update NOAA's nautical charts of the area.

A map of a seamount in the Arctic Ocean created by NOAA's Office of Coast Survey by gathering data with a multibeam echo sounder.

With NOAA's predicted, real-time, and forecasted currents, people can safely dock and undock ships, maneuver them in confined waterways, and safely navigate through coastal waters. This helps to avoid ship collisions or delay the arrival of goods. Image credit: Robert Schwemmer, NOAA National Marine Sanctuaries

The Physical Oceanographic Real-Time System, or 'PORTS,' operates in 20 ports around the country, including along the lower Mississippi. PORTS provides up-to-the-minute information on tides, currents, salinity, water and air temperature, atmospheric pressure, and wind (speed, gusts, and direction). This information helps mariners time the movement of their vessels -- from the smallest recreational craft to the most massive oil tankers -- through more than 50 U.S. seaports and waterways. Port authorities, local officials, and marine pilot associations also use PORTS to determine if a waterway is open and safe for navigation.

The NOAA Ship Rainier is designed and outfitted primarily for conducting hydrographic surveys in support of nautical charting. The ship operates off the U.S. Pacific Coast, and in Alaskan coastal waters. The Rainier is named for Mount Rainier.

There are nearly 3,500,000 square nautical miles of our nation's waters to monitor, understand, and chart. The Office of Coast Survey evaluates the 500,000 square natuical miles that are navigationally significant. Then, each spring, hydrographic field parties set out in vessels to survey sections of the 43,000 square nautical miles deemed to be critical by the Coast Survey's evaluation. Sometimes teams break loose from normal surveying to respond to disasters such as hurricanes.

Employees of the National Geodetic Survey conducted leveling to check the stability of the Washington Monument for the National Park Service in the winter of 2008-2009.

NOAA Ship Bay Hydro docked next to a NOAA tide station in Baltimore, Md.

NOAA Ship Thomas Jefferson, one of the most technologically advanced hydrographic survey vessels in the world, departed its Norfolk, Virginia, homeport on April 6, 2010, to conduct a five-month long effort to map the seafloor and look for hazards to navigation off the Gulf coast.

NOAA's National Geodetic Survey established a high-accuracy vertical control network at the Chesapeake Bay Environmental Center to support coastal restoration, research, testing of new geodetic technologies, and monitoring of the effects of local relative sea-level rise. The network includes over a dozen geodetic bench marks distributed throughout the 510-acre wetland reserve near Graysonville, Maryland, with four deep-rod Surface Elevation Table (SET) marks located in the rapidly deteriorating marsh. Here, NOS employees install stainless steel rods into the ground as part of the process to install a SET. The SETs provide data to model the fate of the marsh in the face of rising water levels and ultimately provide insight into its restoration.

Scientists from the Office of Coast Survey and the University of New Hampshire spent three weeks aboard the U.S. Coast Guard icebreaker Healy in the Arctic using a sophisticated echo sounder to create a three-dimensional map of the sea floor in an area north of Alaska known as the Chukchi Cap. Here, the Healy crew lowers echo sounding equipment into the water. The data collected during the expedition will help scientists better understand the underwater landscape in the region and improve climate and ocean current circulation models.

A group of elephant seals sleep in the sun around a sand dune on Active Point, San Miguel Island, of the Channel Islands National Marine Sanctuary, off the coast of California. Image credit: Robert Schwemmer, NOAA National Marine Sanctuaries

Tools such as Side Scan Sonars are helping NOS understand our marine environment.

Multibeam sonar systems emit sound waves from directly beneath a ship's hull to produce fan-shaped coverage of the sea floor. These systems measure and record the time elapsed between the emission of the signal from the transducers to the sea floor or object and back again. Multibeam sonars produce a 'swath' of soundings (i.e., depths) to ensure full coverage of an area.

Staff from the National Geodetic Survey undertakes a GRAV-D flight to collect aerial gravity data over the Gulf Coast in the spring of 2009.

Seven current meter platforms arrive by truck for the Miami Current Survey Project. The project originated in 2007 after requests for up-to-date current information were received from multiple navigational community and marine resource users. The current survey project supports navigation and the operation of deep draft vessels in the area and additionally benefits various state and federal agencies.

NOAA's air gap technology received the ultimate test on the morning of June 27, 2009. The technology passed with flying colors as the new U.S. Navy LPD ship, the USS New York, sailed down the Mississippi River, clearing the underside of the Huey P. Long Bridge just north of downtown New Orleans by 64 centimeters (2.1 feet). The San Antonio-class $1 billion naval vessel, built in part from steel salvaged from the World Trade Center towers, sailed downriver, heading out for a month of sea trials.

NOAA's National Geodetic Survey and Center for Operational Oceanographic Products and Services are collaborating with the National Estuarine Research Reserve System to establish and monitor coastal land elevations in relation to local sea level throughout the reserve system. This marker from the Chesapeake Bay Reserve in Virginia is part of the required spatial framework needed to establish the reserves as 'sentinel' sites for measuring and monitoring the impacts of climate change on estuarine systems. The inscription reads: 'National Oceanic and Atmospheric Administration; National Estuarine Research Reserve System; National Geodetic Survey.'

NOAA nautical charts, such as this chart of Tampa Bay, Florida, are important tools to help mariners navigate safely at sea. A nautical chart is a graphical portrayal of the marine environment, showing the nature and form of the coast, the depths of the water, character and configuration of the sea bottom, locations of hazards and dangers, the rise and fall of the tides, ocean currents, magnetic variation, regulatory boundaries, and the locations of aids to navigation (e.g., lights, buoys, beacons and other important landmarks).

NOAA Ships Fairweather and Rainier in Alaska. Both ships are designed and outfitted primarily for conducting hydrographic surveys in support of nautical charting, but are capable of many other missions in support of NOAA programs.

With the assistance of the United States Embassy, NOAA's National Geodetic Survey provided technical assistance to the Ministry of Water Resources, General Directorate for Surveying and Mapping in Iraq, for the first Continuously Operating Reference Station (CORS) to be installed by the Iraqi government. CORS is a permanently operating Global Positioning System (GPS) base station, which enables the determination of highly accurate GPS positions. The new Iraqi-installed CORS, part of the Iraqi Geospatial Reference System, will improve the quality, accuracy, and cost of airfield and boundary surveys and other precise positioning activities in Iraq. This CORS looks east over the city of Baghdad and is maintained and operated by the Iraq Ministry of Water Resources.

These images represent three distinct visual sensing techniques. The top picture represents a true-color image, the middle an infrared image, and the bottom an elevation image. The images were taken in March 2008 over Hatteras Island, North Carolina.

NOAA Ship Thomas Jefferson in New York Harbor. The Thomas Jefferson is one of a fleet of research and survey vessels used by NOAA to improve our understanding of the marine environment. The ship is home ported in Norfolk, Virginia, and primarily operates along the Atlantic and Gulf coasts, including Puerto Rico and the U.S. Virgin Islands. The primary mission of the Thomas Jefferson is to conduct hydrographic surveys for updating NOAA's nautical charts.

NOAA Ship Fairweather in Kachemak Bay, Alaska. The Fairweather is designed and outfitted primarily for conducting hydrographic surveys in support of nautical charting, but the ship is capable of many other missions in support of NOAA programs. The Fairweather is equipped with the latest in hydrographic survey technology — multi-beam survey systems; high-speed, high-resolution side-scan sonar; position and orientation systems; hydrographic survey launches; and an on-board data-processing server. The Fairweather is named for Mt. Fairweather in southeast Alaska, which is the highest peak in the Fairweather Range -- the tallest coastal range on Earth.

NOAA's National Geodetic Survey employees level to a pier as part of a larger island-wide project to provide St. Thomas, U.S. Virgin Islands with a vertical datum.

Center for Operational Oceanographic Products and Services National Current Observation Program conducted several major surveys of tidal currents in response to user requests. Data has been collected in southeast Alaska since 2001 to help update tidal current predictions critical to safe navigation and other applications that are published annually in the U.S. Tidal Current Tables. Here, scientists deploy current meter buoys and anchors used for the surveys.

An employee from the Center for Operational Oceanographic Products and Services installs an air gap sensor which measures bridge clearance on the Verrazano-Narrows Bridge, New York. The sensors take readings every six minutes to account for changes in water level, volume of traffic crossing the bridges, and air temperature, all of which cause bridge clearance to fluctuate. As ships become taller, some are passing under bridges with just inches to spare. This new capability is available through NOAA's Physical Oceanographic Real-time System, which provides quality-controlled oceanographic and weather data at U.S. seaports to aid navigation.

The RV Sam Gray, a vessel operated by Gray's Reef National Marine Sanctuary, assisting in the Battle of the Atlantic Expedition Summer 2008. NOAA's Office of National Marine Sanctuaries, in collaboration with the National Park Service, Minerals Management Service, East Carolina University, the University of North Carolina Coastal Studies Institute, and the State of North Carolina, conducted this archaeological expedition to survey ships sunk off the coast of North Carolina during World War II.

A Global Positioning System setup on a benchmark on the top of the NOAA Sentinel at Shell Beach, Louisiana. NOAA Sentinels are water-level observing stations which have been strengthened to deliver real-time storm tide data during severe coastal events. Built to withstand category four hurricanes, these structures maintain an incredible presence, given their size and stature, along the Gulf coast.

An employee from the Center for Operational Oceanographic Products and Services installs an air gap sensor which measures bridge clearance on the Verrazano-Narrows Bridge, New York. The sensor is part of the New York/New Jersey Physical Oceanographic Real-Time System. Information from the sensor is critical for under-bridge clearance, as ships continue to maximize channel depths and widths while, at the same time, push the bounds of bridge heights.

The Hi'ialakai is one of seven former Navy T-AGOS class ships transferred to NOAA. T-AGOS ships are monohull ocean surveillance ships originally designed to gather underwater acoustical data. Hi'ialakai was converted to conduct coral reef and related research in the Hawaiian Islands, primarily in support of NOAA's National Ocean Service.

A hurricane-hardened 'NOAA Sentinel' water level observing station.