Deep-ocean Assessment and Reporting of Tsunamis

Deep-ocean Assessment and Reporting of Tsunamis (DART) is a component of an enhanced tsunami warning system.

By logging changes in seafloor temperature and pressure, and transmitting the data via a surface buoy to a ground station by satellite, DART enables instant, accurate tsunami forecasts. In Standard Mode, the system logs the data at 15-minute intervals, and in Event Mode, every 15 seconds. A 2-way communication system allows the ground station to switch DART into Event Mode whenever detailed reports are needed.

DART II System Diagram
A diagram of the Dart II System
Dart tsunamicover
A tsunami buoy
Water column height on 11 March 2011 (Tōhoku earthquake and tsunami) at DART buoy 21413, 690 NM Southeast of Tokyo
2010 Chile earthquake - NOAA buoy 34142 - water column height short
Plot of measurements from DART buoy 34142 showing the passage of the tsunami generated by the 2010 Chile earthquake. Buoy 34142 is located in the southeastern Pacific Ocean 630 nautical miles (1170 km) southwest of Lima.


Each DART station consists of a surface buoy and a seafloor bottom pressure recording (BPR) package that detects pressure changes caused by tsunamis. The surface buoy receives transmitted information from the BPR via an acoustic link and then transmits data to a satellite, which retransmits the data to ground stations for immediate dissemination to NOAA's Tsunami Warning Centers, NOAA's National Data Buoy Center, and NOAA's Pacific Marine Environmental Laboratory (PMEL). The Iridium commercial satellite phone network is used for communication between 31 of the buoys.[1]

When on-board software identifies a possible tsunami, the station leaves standard mode and begins transmitting in event mode. In standard mode, the station reports water temperature and pressure (which are converted to sea-surface height) every 15 minutes. At the start of event mode, the buoy reports measurements every 15 seconds for several minutes, followed by 1-minute averages for 4 hours.[2]

The first-generation DART I stations had one-way communication ability, and relied solely on the software's ability to detect a tsunami to trigger event mode and rapid data transmission. In order to avoid false positives, the detection threshold was set relatively high, presenting the possibility that a tsunami with a low amplitude could fail to trigger the station.

The second-generation DART II is equipped for two-way communication, allowing tsunami forecasters to place the station in event mode in anticipation of a tsunami's arrival.

Deep-ocean Assessment and Reporting of Tsunamis is officially abbreviated and trademarked as DART.[3]


National Oceanic and Atmospheric Administration’s NOAA have placed Deep-ocean Assessment and Reporting of Tsunami stations in particular areas, areas with a history of generating large tsunamis, to be completely positive that the detection of tsunamis are to be as fast as possible. The year of 2001 was the completion of the first six tsunami detection buoys placed along the northern Pacific Ocean coast. In 2005 the United States president George W. Bush announced a two-year, $3.5 million, plan to install tsunami detecting buoys in the Atlantic and the Caribbean ocean in order to expand the nation’s capabilities to detect tsunamis. With the Pacific Ocean creating 85 percent of the world’s tsunamis[4] , the majority of new tsunami detecting buoy equipment will be installed around the pacific rim, while only seven buoys will be placed along the Atlantic and Caribbean coast because even though tsunamis are rare in the Atlantic, there have been records of deadly tsunamis being reported in the Atlantic. Roughly $13.8 million of the governments funding was used to procure and install exactly 32 pressure sensors on the ocean bottom to detect tsunamis and collect data such as the height and speed of the approaching tsunami. This proposed system, stated by the John H. Marburger the White House’s Office of Science and Technology Policy, should provide the United States’ Tsunami Warning Centers with nearly one hundred percent coverage for any approaching tsunamis as well as decline all false alarms to just about zero.[4] During all these improvements and upgrades of the current system, roughly three fourths of the tsunami warnings were discovered to be unnecessary and a waste of money. A few years later in 2008 there are now roughly 40 tsunami detection buoys placed in the Pacific Ocean by NOAA. The upgraded DART buoys were originally developed to maintain but to mostly improve the timing of detection of a tsunami. With an improved detection time for tsunamis, that is more time to save lives, warning guidance and international coordination.


The DART buoy technology was developed at PMEL,[5] with the first prototype deployed off the coast of Oregon in 1995. In 2004, the DART® stations were transitioned from research at PMEL to operational service at the National Data Buoy Center (NDBC), and PMEL and NDBC received the Department of Commerce Gold Medal "for the creation and use of a new moored buoy system to provide accurate and timely warning information on tsunamis".[6]

In the wake of the 2004 Indian Ocean earthquake and its subsequent tsunamis, plans were announced to deploy an additional 32 DART II buoys around the world.[7] These would include stations in the Caribbean and Atlantic Ocean for the first time.

The United States' array was completed in 2008 totaling 39 stations in the Pacific Ocean, Atlantic Ocean, and Caribbean Sea. The international community has also taken an interest in DART buoys and as of 2009 Australia, Chile, Indonesia and Thailand have deployed DART buoys to use as part of each country's tsunami warning system.

In the 2018 budget justification for NOAA, the Trump administration proposed eliminating the DART system as part of a 56% cut to the tsunami warning program.[8]


Deep-ocean Assessment and Reporting of Tsunami buoy systems are made up of three parts. There is a pressure recorder anchored to the bottom of the sea floor. A moored surface buoy and an acoustic transmission link that is connected to the pressure recorder and sends data from the anchored pressure recorder to the surface buoy.[9] The surface buoy has a two and a half meter diameter fiberglass disk covered with foam and has a gross displacement of 4000 kg.[10] The mooring line connecting the surface buoy and the pressure recorder is a nineteen millimeter nylon line that has a tensile strength of 7100 kg.[10] The data being sent from the anchored pressure recorder and the surface buoy consists of temperature and pressure of the surrounding sea water. It retrieves and releases data every 15 seconds to get an average reading of the current weather conditions.[11] Once the data is retrieved to the surface buoy, the pressure data is converted to an average height of the waves surrounding the buoy. The data containing the temperature of the surrounding sea water is important to the calculations because temperature can affect pressure, and sea temperature is required to get that much more of an accurate reading of the ocean swells. Because swell size of ocean varies constantly, the system has two modes of reporting data, standard mode and event modes.[12] Standard mode is the more common mode of the two because standard mode sends the estimated sea surface height and the time these calculations were recorded every 15 minutes.[9] If the software receives data that is not within the recent data averages, the system automatically switches to event mode. Event mode transmits data every 15 seconds and calculates the average sea surface height and the time when data being recorded every minute. If no further data is received that is not out of the averages being calculated at the time, it switches back to standard mode after four hours.[12] When NOAA released the first six DART buoys, their system only had a one way communication system. It was not until 2005 when the first generation of the DART buoy was upgraded to the second generation of the DART buoy. After 2005 the Dart buoys started using Iridium communication satellites that abled you to not only retrieved information but to also send information to a DART.[13] The two-way communications between Tsunami Warning Centers and the pressure recorder made it possible to manually set DART buoys in event mode in case of any suspicion of a possible in-coming tsunamis. To make sure communications are always in contact and secure, the DART buoys have two communication systems; two independent and a redundant communication system.[13] With these updated and reliable communicating systems, data can now be sent where it needs to be sent around the world.

See also


  1. ^ tracks tsunami buoys for NOAA
  2. ^ "Archived copy". Archived from the original on 2010-03-06. Retrieved 2010-03-01.CS1 maint: archived copy as title (link)
  3. ^ DART website with Patent Licensing Application form
  4. ^ a b (January 15, 2005 Saturday). Tsunami Detection To Expand; More Protection for U.S. Coastal Areas. The Washington Post, Retrieved from
  5. ^ DART development Publications & References, 2011-11-15
  6. ^ Note: The Gold Medal is granted for distinguished contributions and is the highest honorary recognition bestowed by the Department of Commerce. Because so many people contributed to this success, the Gold Medal was presented as an organizational award.
  7. ^
  8. ^ NOAA FY 2018 Congresstional [sic] Justification, p. 408. Retrieved June 2, 2017 from
  9. ^ a b (2015). Deep Ocean Tsunami Detection Buoys. Australian Government; Bureau of Meteorology.
  10. ^ a b Meinig, C., S.E. Stalin, A.I. Nakamura, H.B. Milburn (2005), Real-Time Deep-Ocean Tsunami Measuring, Monitoring, and Reporting System: The NOAA DART II Description and Disclosure.
  11. ^ Deep-ocean Assessment and Reporting of Tsunamis (DART®) Description. (2011, July 27). Retrieved March 24, 2015, from Archived 2010-03-06 at the Wayback Machine
  12. ^ a b Deep-ocean Assessment and Reporting of Tsunamis (DART®) Description. (2011, July 27). Retrieved April 21, 2015, from Archived 2010-03-06 at the Wayback Machine
  13. ^ a b Mungov, G., Eblé, M., & Bouchard, R. (2013). DART Tsunameter Retrospective and Real-Time Data: A Reflection on 10 Years of Processing in Support of Tsunami Research and Operations. Pure & Applied Geophysics, 170(9/10), 1369-1384. doi:10.1007/s00024-012-0477-5

External links

Aircraft Meteorological Data Relay

Aircraft Meteorological Data Relay (AMDAR) is a program initiated by the World Meteorological Organization.

AMDAR is used to collect meteorological data worldwide by using commercial aircraft.

Data is collected by the aircraft navigation systems and the onboard standard temperature and static pressure probes.

The data is then preprocessed before linking them down to the ground either via VHF communication (ACARS)

or via satellite link ASDAR.

A detailed description is given in the AMDAR Reference Manual (WMO-No 958) available from the World Meteorological Organization,

Geneva, Switzerland.

Automated Meteorological Data Acquisition System

AMeDAS (Automated Meteorological Data Acquisition System), commonly known in Japanese as "アメダス" (amedasu), is a high-resolution surface observation network developed by the Japan Meteorological Agency (JMA) used for gathering regional weather data and verifying forecast performance. The system began operating on 1 November 1974, and currently comprises 1,300 stations throughout Japan (of which over 1,100 are unmanned), with an average separation of 17 km (11 mi).

Observations at manned stations cover weather, wind direction and speed, types and amounts of precipitation, types and base heights of clouds, visibility, air temperature, humidity, sunshine duration, and atmospheric pressure. All of these (except weather, visibility and cloud-related meteorological elements) are observed automatically.

At unmanned stations, observations are performed every 10 minutes. About 700 of the unmanned stations observe precipitation, air temperature, wind direction and speed, and sunshine duration, while the other stations observe only precipitation.

For about 280 stations (manned or unmanned) located in areas of heavy snowfall, snow depth is also observed.

All the observational data is transmitted to the AMeDAS Center at JMA Headquarters in Tokyo on a real time basis via dedicated telephone lines. The data is then delivered to the whole country after a quality check.

As well as weather conditions, AMeDAS is also used in the observation of natural disasters. Temporary observation points are set up in areas where there are signs of volcanic eruptions or earthquakes.

Automatic weather station

An automatic weather station (AWS) is an automated version of the traditional weather station, either to save human labour or to enable measurements from remote areas. An AWS will typically consist of a weather-proof enclosure containing the data logger, rechargeable battery, telemetry (optional) and the meteorological sensors with an attached solar panel or wind turbine and mounted upon a mast. The specific configuration may vary due to the purpose of the system. The system may report in near real time via the Argos System and the Global Telecommunications System, or save the data for later recovery.In the past, automatic weather stations were often placed where electricity and communication lines were available. Nowadays, the solar panel, wind turbine and mobile phone technology have made it possible to have wireless stations that are not connected to the electrical grid or hardline telecommunications network.

Citizen Weather Observer Program

The Citizen Weather Observer Program (CWOP) is a network of privately owned electronic weather stations concentrated in the United States but also located in over 150 countries. Network participation allows volunteers with computerized weather stations to send automated surface weather observations to the National Weather Service (NWS) by way of the Meteorological Assimilation Data Ingest System (MADIS). This data is then used by the Rapid Refresh (RAP) forecast model to produce short term forecasts (3 to 12 hours into the future) of conditions across the contiguous United States. Observations are also redistributed to the public.

Coastal-Marine Automated Network

The Coastal-Marine Automated Network (C-MAN) is a meteorological observation network along the coastal United States. Consisting of about sixty stations installed on lighthouses, at capes and beaches, on near shore islands, and on offshore platforms, the stations record atmospheric pressure, wind direction, speed and gust, and air temperature; however, some C-MAN stations are designed to also measure sea surface temperature, water level, waves, relative humidity, precipitation, and visibility.

The network is maintained by the National Data Buoy Center (NDBC) of the National Weather Service (NWS), which is part of National Oceanic and Atmospheric Administration (NOAA), and data is ingested into numerical weather prediction computer models. It was created in the early 1980s to maintain observations that were about to be discontinued by other programs. Data is processed and transmitted similarly to the moored buoy system.

In 2002, C-MAN was added to the NOAA Observing System Architecture (NOSA).


Dart or DART may refer to:

Dart (missile), a projectile weapon

Dart, the equipment in the game of darts

Dart (sewing), a fold sewn into the fabric of a garment


A dropsonde is an expendable weather reconnaissance device created by the National Center for Atmospheric Research (NCAR), designed to be dropped from an aircraft at altitude over water to measure (and therefore track) storm conditions as the device falls to the surface. The sonde contains a GPS receiver, along with pressure, temperature, and humidity (PTH) sensors to capture atmospheric profiles and thermodynamic data. It typically relays this data to a computer in the aircraft by radio transmission.

Global Atmosphere Watch

The Global Atmosphere Watch (GAW) is a worldwide system established by the World Meteorological Organization – a United Nations agency – to monitor trends in the Earth's atmosphere. It arose out of concerns for the state of the atmosphere in the 1960s.

Global Sea Level Observing System

The Global Sea Level Observing System (GLOSS) is an Intergovernmental Oceanographic Commission program whose purpose is to measure sea level globally for long-term climate change studies. The program's purpose has changed since the 2004 Indian Ocean earthquake and the program now collects realtime measurements of sea level. The project is currently upgrading the over 290 stations it currently runs, so that they can send realtime data via satellite to newly set up national tsunami centres. They are also fitting the stations with solar panels so they can continue to operate even if the mains power supply is interrupted by severe weather. The Global Sea Level Observing System does not compete with Deep-ocean Assessment and Reporting of Tsunamis as most GLOSS transducers are located close to land masses while DART's transducers are far out in the ocean.


IWXXM (ICAO Meteorological Information Exchange Model) is a format for reporting weather information in XML/GML. IWXXM includes XML/GML-based representations for products standardized in International Civil Aviation Organization (ICAO) Annex III and World Meteorological Organization (WMO) No. 49, Vol II, such as METAR/SPECI, TAF, SIGMET, AIRMET, Tropical Cyclone Advisory and Volcanic Ash Advisory. IWXXM products are used for operational exchanges of meteorological information for use in aviation.

Unlike the traditional forms of the ICAO Annex III / WMO No. 49 products, IWXXM is not intended to be directly used by pilots. IWXXM is designed to be consumed by software acting on behalf of pilots, such as display software.

List of weather instruments

For financial instruments concerning weather, see weather insurance.This is a list of devices used for recording various aspects of the weather.

NOAA Center for Tsunami Research

The NOAA Center for Tsunami Research (NCTR), located at the Pacific Marine Environmental Laboratory (PMEL) in Seattle, Washington, performs research in support of tsunami forecast models to increase the speed and accuracy of operational forecasts and warnings, tsunami inundation models to predict tsunami impacts on coastal communities, and tsunami measurement/detection technology for optimally designed networks of tsunami buoys.

National Data Buoy Center

The National Data Buoy Center (NDBC) is a part of the National Oceanic and Atmospheric Administration's (NOAA) National Weather Service (NWS). NDBC designs, develops, operates, and maintains a network of data collecting buoys and coastal stations. The NBDC is located in southern Mississippi as a tenant at the John C. Stennis Space Center, a National Aeronautics and Space Administration (NASA) facility.

Pacific Tsunami Warning Center

The Pacific Tsunami Warning Center (PTWC) is one of two tsunami warning centers that are operated by NOAA in the United States. Headquartered on Ford Island, HI, the PTWC is part of an international tsunami warning system (TWS) program and serves as the operational center for TWS of the Pacific issuing bulletins and warnings to participating members and other nations in the Pacific Ocean area of responsibility. It is also the regional (local) warning center for the State of Hawaii. The other tsunami warning center is the National Tsunami Warning Center (NTWC) in Palmer, Alaska, serving all coastal regions of Canada and the United States except Hawaii, the Caribbean Sea and the Gulf of Mexico.

The PTWC was established in 1949, following the 1946 Aleutian Island earthquake and a tsunami that resulted in 165 casualties in Hawaii and Alaska.

The PTWC uses seismic data as its starting point, but then takes into account oceanographic data when calculating possible threats. Tide gauges in the area of the earthquake are checked to establish if a tsunami has formed. The center then forecasts the future of the tsunami, issuing warnings to at-risk areas all around the Pacific basin if needed.

Remote Automated Weather Station

The Remote Automatic Weather Stations (RAWS) system is a network of automated weather stations run by the U.S. Forest Service (USFS) and Bureau of Land Management (BLM) and monitored by the National Interagency Fire Center (NIFC), mainly to observe potential wildfire conditions.

Unlike the automated airport weather stations which are located at significant airports, RAWS stations are often located in remote areas, particularly in national forests. Because of this, they usually are not connected to the electrical grid, but rather have their own solar panels, and a battery to store power for overnight reporting. Some instead run on a generator. In both cases, data important to operating the station itself, such as battery voltage or fuel level, is often included in the hourly reports.

Also because of the remote locations, most communicate with a modem via telephone, or via a VSAT connection to a GOES satellite.

In this regard, they are similar to mesonets and may be mesonets if the distance between stations (spatial resolution) is sufficiently dense. They often lack the consistently high-quality data needed for use in numerical weather prediction and climatology, however. Road Weather Information System (RWIS) may likewise be self-powered and located in remote areas.

Road Weather Information System

A Road Weather Information System (RWIS) comprises automatic weather stations (technically referred to as Environmental Sensor Stations (ESS)) in the field, a communication system for data transfer, and central systems to collect field data from numerous ESS. These stations measure real-time atmospheric parameters, pavement conditions, water level conditions, and visibility. Central RWIS hardware and software are used to process observations from ESS to develop nowcasts or forecasts, and display or disseminate road weather information in a format that can be easily interpreted by a manager. RWIS data are used by road operators and maintainers to support decision making. Real-time RWIS data is also used by Automated Warning Systems (AWS). The spatial and temporal resolution can be that of a mesonet. The data is often considered proprietary although it is often ingested into numerical weather prediction models.

Undersea mountain range

Undersea mountain ranges are mountain ranges that are mostly or entirely underwater, and specifically under the surface of an ocean. If originated from current tectonic forces, they are often referred to as a mid-ocean ridge. In contrast, if formed by past above-water volcanism, they are known as a seamount chain. The largest and best known undersea mountain range is a mid-ocean ridge, the Mid-Atlantic Ridge. It has been observed that, "similar to those on land, the undersea mountain ranges are the loci of frequent volcanic and earthquake activity".

Voluntary observing ship program

Due to the importance of surface weather observations from the surface of the ocean, the voluntary observing ship program, known as VOS, was set up to train crews how to take weather observations while at sea and also to calibrate weather sensors used aboard ships when they arrive in port, such as barometers and thermometers. An Automatic Voluntary Observing Ships (AVOS) System is an automated weather station that transmits VOS program reports.

Wave base

The wave base, in physical oceanography, is the maximum depth at which a water wave's passage causes significant water motion. For water depths deeper than the wave base, bottom sediments and the seafloor are no longer stirred by the wave motion above.

Ocean zones
Sea level
Earth-based meteorological observation systems and weather stations


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