The North Atlantic Ocean Stations Agreement


At the end of World War II, international civil aviation expanded at an increased rate; when the Provisional International Civil Aviation Organization (PICAO) came into being on 6 June 1945, the PICAO (and later ICAO) and its regional meetings were the proper forum of exchange on the establishment and operations of safe and efficient international air services. Under the Convention on International Civil Aviation, each state is primarily responsible for providing in its territory, so far as it may find practicable, air navigation services to facilitate international air transport. In some instances, the desired facilities had to be located in inhabited regions and in areas of uncertain sovereignty.


The recommendations of the PICAO Dublin Regional Meeting, held in March 1946, recognized that there was a serious lack of weather observation and air navigational facilities over the world’s most heavily travelled trans-oceanic corridor, i.e. the North Atlantic. Moreover, as underlying sovereign States had little to gain domestically in providing what would have been enormously expensive services for over-flying international services, the Dublin meeting suggested that a network of ships be stationed at specific points to provide all necessary observations and communications relay points, and to serve as emergency air-sea rescue bases.


The question of meteorological services for international air operations over the North Atlantic Ocean was again discussed by the delegates of interested States attending the First Interim Assembly of the Provisional International Civil Aviation Organization (PICAO) in May 1946. As a result, a special conference was convened by PICAO in London in September 1946 with all interested parties. The conference considered to retain wartime Atlantic Ocean weather ship stations and decided that affected Member States would financially support the continued operations of these stations in the form of a Joint Support action. This action was supported by the International Meteorological Organization (IMO, the predecessor of the World Meteorological Organization), which had developed a scheme with vessels providing meteorological surface observations to stations ashore. However the airliner required meteorological information about the atmosphere up of 20,000 feet and over; aviation made imperative the need for a system of forecasting so exact and reliable that airlines can work out flight plans which would avoid headwinds and other unfavourable weather and take advantage of tailwinds. Obviously, this could not be provided by the existing IMO observations with the rapid development of civil aviation after 1945 and the aircraft overtaking the ocean liner as the major means of transport between Europe and North America.


The resulting Agreement provided for the operation of thirteen weather stations (i.e. stations A to M) located at strategic points across the North Atlantic covering constant meteorological information, navigational aids, search and rescue facilities for aviation and shipping. The 1946 North Atlantic Ocean Stations (NAOS) Agreement was revised by the Second Conference on ICAO North Atlantic Ocean Stations, which was convened in London in May 1949. Under the revised Agreement, only ten (later reduced to 9 fixed stations) weather stations served by 25 vessels would be maintained in the North Atlantic; the main responsibility of ICAO was to administer the joint program of operation of the stations in consultation with such other international organizations as required. From the inception of this network, its meteorological data were also widely disseminated on the WMO telecommunications circuits, and thus contributed not only to aviation requirements but also to all other meteorological purposes. Fourteen nations were participating in the 1949 agreement.


Among the ten stations, six stations were allocated to the United States, some of which would be operated jointly. Such case was for station B, named Baker (the stations were called by the same names as used in the International Phonetic Alphabet. Station B was later renamed Bravo), where the frigate HMCS St. Stephen (K454) from the Canadian Coast Guard fleet, with a complement of civilian staff of five meteorological observers, served in the North Atlantic, on alternate patrols with the United States from 27 September 1947 till August 1950, by which time, for economic reasons, it was decided that Canada would abandon her half share in the Atlantic work.


USCGC Bibb (WPG-31) Coast Guard ship

The value of these stations for the secondary purposes, namely search and rescue services, had also been amply demonstrated since the inception of the network and would continue to be so during its lifetime. Their use for such purposes was illustrated, for instance, by a dramatic rescue at sea on 14 October 1947 for the American-owned Boeing 314 flying boat Bermuda Sky Queen, carrying sixty-nine passengers flying from Foynes, Ireland to Gander, Newfoundland. Gale force winds had slowed her progress and the aircraft was running low on fuel. Too far from Newfoundland and unable to make it back to Ireland, Captain Charles Martin decided to fly toward USCGC Bibb (WPG-31) which was on Ocean Station Charlie in the North Atlantic. The plane’s captain decided to ditch and have his passengers and crew picked up by Bibb. In 10-meter seas, the transfer had been both difficult and dangerous. The rescue made headlines throughout the country and upon their arrival in Boston, Bibb and her crew received a hero’s welcome for having saved all those aboard the ditched Bermuda Sky Queen. This act of rescue remained an epic story in the annals of lifesaving at sea and was not the only example.


On Friday, 27 February 1953, the United States Coast Guard Cutter "Coos Bay", rescued the ten-man crew of a U. S. Navy Patrol aircraft which was forced down in the North Atlantic. The “Coos Bay" is one of the 25 ships used to maintain the ICAO Ocean Station Network in the North Atlantic


The 1949 North Atlantic Ocean Stations (NAOS) Agreement (originally expiring on 1 July 1953 and extended for one year by a special protocol signed in the summer of 1952) was revised by the Fourth Conference on the North Atlantic Ocean Stations which was convened in Paris from 9 to 25 February 1954. Under the revised Agreement and for reasons of economy, only nine weather stations served by 21 vessels would be maintained in the North Atlantic.



Weather balloon launched aboard the Cirrus ship

In June 1959, the Council decided to convene the Fifth NAOS Conference early in 1960. It had been requested to do so under Article  XIV of the Agreement by the Netherlands Government, which considered that, mainly because of the rise in operating expenses since the Fourth Conference (held in Paris from 9 to 15 February 1954), the European States operating weather ships, and in particular the Netherlands, were bearing  a disproportionate share of the cost of the ocean stations network and that the distribution of responsibilities under the Agreement needed to be adjusted to present conditions. The Fifth NAOS Conference met in The Hague from 17 to 29 March 1960 for the limited purpose of revising the method of calculating cash adjustments under Article III of the Agreement.  In recognition of the fact that the contributions of the North American operating States exceeded their theoretical responsibilities, the Conference recommended the establishment of a common fund into which would be put cash received from Australia, Venezuela and any State subsequently contributing to the Ocean Stations scheme and specified contributions by the European States, and which would be divided annually among all States parties to the Agreement in  proportion to their theoretical responsibilities. 


Reports received from governments indicated that, in 1961, there were 42,556 complete transatlantic crossings by civil aircraft that benefited from the communications, meteorological and search and rescue services provided by the North Atlantic Ocean Stations.


Emblem of the Flight Safety Foundation

The Flight Safety Foundation Award for Distinguished Service, for assistance to aviation throughout the world in the achievement for safer utilization of aircraft, was given in Athens, Greece on 7 November 1963 to the personnel of the ICAO weather ships. Flight Safety Foundation, with Headquarters in Alexandria, Virginia, USA, is an independent, non-profit, international organization dedicated to research, education, advocacy and publishing in the field of air safety, with the vast majority of the world's airlines and aircraft manufacturers holding membership of the foundation.


The unit cost of the services provided by the ocean weather stations in 1964 was calculated at US$84 per crossing, which was slightly lower than the corresponding figure for 1963 ($85.4). Actually, the trend has been steadily downward, because the number of crossings has been increasing faster than the costs chargeable to the NAOS scheme.


In 1965, the number of transatlantic flights considered to have benefited from the services provided by the North Atlantic Ocean Stations was 66,478, 10,751 (about 19.3%) more than in 1964.


At the beginning of 1968, a total of 21 ships were needed to man the nine stations continuously. Each station consisted of a ten-mile square patrolled by one ship; ships stayed on station for a three-week period or until relieved, and it therefore took between two and three ships to man one station continuously, depending upon how far that station was from their home bases. It was the responsibility of Canada and the United States to man the four most westerly stations (stations B, C, D and E); the other five stations (stations A, I, J, K and M) were manned by France, the Netherlands, Norway/Sweden and the United Kingdom (see picture here-below showing the position of those stations). In addition, Australia, Belgium, Czechoslovakia, Denmark, Germany, Iceland, India, Ireland, Israel, Italy, Japan, Mexico, Pakistan, Spain, Switzerland and Venezuela regularly made cash contributions to defray certain of the costs of the service. The allocation of responsibilities, whether operation of ships or contribution of cash, between the countries concerned was based to a major extent (eighty per cent) on the aeronautical benefits as represented by the number of flights made by the civil aircraft of each country across the North Atlantic, and to a lesser extent (twenty per cent) upon the non-aeronautical benefits, such as the better forecasting of surface weather, which each country may receive.


The Sixth ICAO Joint Financing Conference on North Atlantic Ocean Stations was held at the ICAO’s European Office in Paris (3 bis Villa Emile Bergerat) from 5 to 22 March 1968. Sixteen of the eighteen States parties to the 1954 Agreement participated; five of the ten non-signatory user States and six interested international organizations were represented by observers. The Conference reached a number of conclusions concerning the NAOS scheme and made various recommendations concerning its technical and financial aspects. The Conference agreed that the scheme should be continued for another five years under ICAO administration. It concluded that the meteorological services provided by the NAOS vessels were still essential for both aeronautical and non-aeronautical purposes and should be considered as primary services; search and rescue, communication, navigational aid and other services were now ancillary but worth maintaining as long as the vessels were kept in operation. It recommended that WMO should study, in cooperation with ICAO, the most economical means of obtaining, after 30 June 1973, the meteorological data indispensable to international civil aviation provided by the ocean stations. The Conference considered that the existing nine stations should be maintained at their present locations. As far as the financing of the scheme is concerned, the Conference decided that the ratio of 80% for aeronautical benefits (as measured by the number of complete North Atlantic crossings by civil aircraft) to 20% for non-aeronautical benefits should be maintained for cost sharing purposes at least through the nineteenth year of the Agreement (i.e. to 30 June 1973). 


In the course of time, aviation made impressive advances and cruising altitudes rose to levels above the prevailing weather. The value of the network to aviation therefore diminished steadily, whereas its importance to meteorology, which itself had made substantial scientific progress, continuously increased for forecasting, climatology, and research.


It therefore gradually became increasingly clear that any long-term future for the NAOS network would rest with WMO rather than ICAO. Eventually the Seventh ICAO Conference on NAOS held in Paris in 1972 decided that the system under the administration of ICAO should be terminated on 30 June 1975 and that WMO should develop a new Agreement if the network remained in existence after that date. The transfer of NAOS from ICAO to WMO marked the end of the system as an essential aeronautical requirement and the beginning, under WMO, of a new phase as a general meteorological facility within the framework of the World Weather Watch. The new network design assessments by WMO resulted in specifications for a composite observing system for the North Atlantic, including a few NAOS vessels as well as polar orbiting and geostationary satellites, drifting buoys and so on. The last vessel was phased out in 1986.


United Nations New York - 19 September 1968

World Weather Watch

The stamp depicts a radarscope, and globes in the form of a polar-aspect azimuthal projection that appears to be based on a projection developed by the National Snow and Ice Data Center (NSIDC).

The Board which administers the North Atlantic Ocean Stations (NAOS) Agreement held its ninth session from 25 to 28 June 1984 at the WMO headquarters in Geneva under the chairmanship of Dr D. N. Axford (United Kingdom). All Contracting Parties to the Agreement and three other countries were represented as well as the COST-43 project. At this session, the Board's main concern was the continuation of NAOS after 1985. From the discussions it became clear that, in the view of the majority, the NAOS system could only be maintained for another three-year period up to 1988 which would have to see a transition to a cost-effective Composite Observing System for the North Atlantic (COSNA). The need was urgent therefore to build up this new system; upper-air observations from a reduced NAOS network would probably still be needed throughout this transitional period. The actual manning of the NAOS stations would depend upon the level of implementation and the quality of data produced by the new observing systems, such as Aircraft Satellite Data Relay (ASDAR), the Automated Shipboard Aerological Programme (ASAP) and drifting buoys, taking account of the results of observing systems experiments and network studies. The NAOS Agreement should therefore be maintained with a measure of flexibility as regards the manning of the stations. The Board foresaw a likely need for an extraordinary session later in 1984 to consider amendments proposed by Contracting Parties and establish the legal foundation for such an Agreement, to be operative for the period 1986-1988. The Board welcomed and encouraged all activities on drifting buoys, ASDAR, ASAP and other programmes, especially those which aimed at demonstrating the cost-effectiveness of new marine observing systems.

The US Navy patrol frigate PF-58, named Abilene, was used as air-sea rescue station during World War II and continued its routine weather patrols until 24 March 1946. The ship was then sold to the Netherlands on 5 May 1947 and renamed Cirrus. Located at the station M (also called Mike), just south of the Arctic Circle, this Dutch ship S.S. Cirrus became one of the 21 vessels that manned ICAO weather stations across North Atlantic. The Cirrus was scrapped in 1969. In December 1962, United Nations Photographer Marvin Bolotsky visited the Cirrus and produced a series of photographs, some of which are shown on the first day covers commemorating the World Weather Watch programme in 1968 and 1989; the ship had a crew of more than 50 and remained at its position for a period of generally 35 days before being relieved by another weather ship.


Both covers seen here-below illustrate the Cirrus ship at sea. In addition, the 1968 issue illustrates the preparation of a balloon with a radiosonde attached; as the balloon rises, signals transmitted by the radiosonde to the ship will enable observers to determine air temperature, pressure and humidity at a number of levels. It is interesting to note that the 1989 cover commemorating the 25th anniversary of the World Weather Watch still shows the Cirrus ship and a photograph of a Meteorological Officer taken on the Cirrus in 1962, although the latter ship had been scrapped in between and the ICAO NAOS Agreement had ceased to exist; moreover, the WWW programme had been established in 1963, so that its 25th anniversary should have been celebrated in 1988, and not in 1989.


Without the vital, organized, multi-nationally supported meteorological, navigational, supplemental air traffic control, and search and rescue services provided by the ocean vessels, such early and safe civil air transport operations over the North Atlantic would not have been possible.


Excerpt from Le Journal de l’UNESCO (Le Courrier), Volume III, No 10, Novembre 1950, Page 7.

Weather balloon launching from the ship S.S. Cirrus under the ICAO Agreement named North Atlantic Ocean Stations (NAOS).


Belgium – 17 April 1958 - World’s Fair Expo 58

United Nations series issued for the purpose of financing the UN pavilion during the 1958 Brussels World Fair. In the background (bottom-right): Oceanic navigation station ship.



Newsletter released by the Paris Office announcing the Third Conference on North Atlantic Ocean Stations (NAOS) held at the Royal Pavilion in Brighton, England, from 8 to 15 July 1953. The agenda of the Brighton Conference was confined to consideration of the re-allocation of responsibilities and distribution under the existing Agreement.


Location of the 9 weather stations in 1960 in the North Atlantic Ocean. The stations were called by the same names as used in the International Phonetic Alphabet.


December 1962 – Picture taken by UN Photographer Marvin Bolotsky,

when he visited the Dutch ship SS Cirrus.

Captain A. Koster and J.W. Fredericks, Chief Officer, plotting the ship’s position on the chart.



Front and back of picture taken on the M.S. Coast Guard Cutter Spencer ship, one of the ICAO weather ships.

Spencer was assigned to the US Navy's Seventh Fleet, in the Pacific in late 1944, where she served as a Communications Command Ship. There she was credited with taking part in numerous amphibious assaults including Luzon and Palawan in the Philippines Campaign. After the war, Spencer returned to her Coast Guard duties, serving in the Atlantic Ocean. Here she provided navigational assistance for the fledgling Trans-Atlantic air industry and acted as a search and rescue platform both ships and aeroplanes.



Weather ship S.S. Cirrus - Launching of the weather balloon filled with hydrogen and equipped with radio gear.

Nabisco, manufacturers of Vita-Brits, in cooperation with the United Nations Association of Australia (UNAA), developed in 1969 a project named “The United Nations in Action” with a series of 24 cereal trading cards to help people to know more of this magnificent world-wide Organization. The above card No. 18 (recto and verso) is related to ICAO and the North Atlantic Ocean Ships.

Nabisco (abbreviated from the earlier name National Biscuit Company) is an American manufacturer of cookies and snacks headquartered in East Hanover, New Jersey. The company is a subsidiary of Illinois-based Mondelēz International.


With pictures taken on the SS Cirrus, the above issue of 19 September 1968 commemorates the World Weather Watch (WWW) programme developed by the World Meteorological Organization (WMO), an Agency of the United Nations headquartered in Geneva, Switzerland. Established in 1963, the World Weather Watch -the core of the WMO programmes- combines observing systems, telecommunication facilities, and data-processing and forecasting centers to make available meteorological and related environmental information needed to provide efficient services in all countries.


19 September 1968 – First Day Cover commemorating the World Weather Watch (WWW) programme. The cachet shows various elements of WWW global observing system, built upon existing sub-systems (both surface- and space-based), i.e. ships, weather radars, satellites and aircraft. The inscription on the ship reads “STATION METEO. K”, referring the weather station K (Kilo), as organized under the ICAO Agreement named North Atlantic Ocean Stations (NAOS).

This issue was sponsored by the Schering Laboratories. Marketed by Schering, Coricidin is used to alleviate coughs and includes chlorpheniramine for people with high blood pressure.


This issue of 21 April 1989 commemorates the 25th anniversary (although with one year behind the actual anniversary date) of the World Weather Watch (WWW) programme developed by the World Meteorological Organization (WMO). Pictures were taken on the SS Cirrus in 1962.