SCIENCE AND THE SEA 



aircraft on a transocean flight. Accurate information on the veloc- 

 ity and direction of winds at several levels along established routes 

 is essential to proper loading and fueling prior to an overseas flight. 

 The daily weather observational program of each ocean station 

 vessel consists of: 



(1) All foreign ocean station vessels and two of the six United 

 States ocean station vessels. BRAVO and NOVEMBER, make and 

 report hourly surface observations. The remaining ocean station 

 vessels report surface observations every 3 hours. These surface 

 observations include wind, weather, visibility, pressure, air tempera- 

 ture and humidity, sea temperature, direction, period and height of 

 waves, and details regarding cloud formation. 



(2) Upper wind observations, by radar, to an average height 

 of about 54,600 feet, every 6 hours. 



(3) Radiosonde observations (pressure, temperature and 

 humidity), to an average height of about 80,400 feet, every 12 hours. 

 These upper air observations involve launching of a gas-filled balloon 

 equipped with a radar reflector and or a miniature radio transmitter. 



Reports from United States North Atlantic Ocean Station Vessels 

 are forwarded by radio to the U. S. Weather Bureau collection center 

 at Washington, D. C. and those from the North Pacific waters "are 

 sent to the Coast Guard radio station in San Francisco, California. 

 Distribution of the data is made to domestic meteorological offices 

 over teletypewriter circuits and to foreign services by radiotelegraph 

 and radioteletypewriter broadcasts. Observations originated by 

 weather ships maintained by other countries are relayed to the U. S. 

 Weather Bureau along with other weather data in international radio 

 exchanges. All weather observations are prepared fo^ transmission 

 in international weather codes. 



Reports furnished by weather ships, along with other reports 

 received from merchant vessels and continental and island stations, 

 complete the synoptic and upper air meteorological coverage over 

 the Northern Hemisphere. These data are first plotted on charts for 

 the surface and for several levels in the upper atmosphere. Upper 

 air charts show temperature, wind distribution and moisture values 

 for the 850 millibar (averaging 4.800 feet above sea level), 700 mb. 

 (about 10,000 feet), 500 mb. {about 18,000 feet). 300 mb. (about 30,000 

 feet). 200 mb. (about 40.000 feet) and 100 mb. (about 54,000 feet), 

 constant pressure surfaces. From these charts, the meteorologist 

 prepares weather forecasts and advisories for scheduled ocean flights. 

 Frequently, because of the distance between ocean stations, he must 

 forecast conditions over a large area of the route on the basis of 

 successive upper air reports from a single ocean station vessel. 

 Hence, the accuracy of data is of paramount importance. 



Flight plans are made on the basis of conditions shown on the 

 weather charts. Aircraft, of course, are primarily interested in 

 making accurate determinations of fuel requirements and maximum 

 payloads that can be carried with safety. The route and flying 

 altitude is selected by the pilots to take maximum advantage of 

 favorable weather and winds so the flight can be completed in the 

 shortest possible time. Ocean flights sometimes follow one of the 

 contour lines shown on a constant pressure chart for as much of the 

 route as possible in order to take advantage of the favorable winds. 

 This technique is familiarly known as "pressure pattern flying." 



There have been many occasions when upper air reports from 

 weather ships provided the only data on which the meteorologist was 

 able to forecast the development of storms over the oceans. Apart 

 from the large number of lives saved by the ocean station vessels 

 and the reliable forecasts made possible by their observations, the 

 mere presence of these stations takes a considerable strain off the 

 minds of pilots. 



In addition, an aircraft can obtain reports of observations from 

 an ocean station vessel in plain language or "Q" code, or in the ap- 

 propriate international meteorological code, according to the method 

 requested by the aircraft. As English speaking operators are 

 carried on commercial transocean flights, "Q" codes are seldom used, 

 and an intended change in ICAO procedures will abolish "Q" codes 

 for ship to aircraft transmissions. 



OCEANOGRAPHIC DATA COLLECTION 



United States ocean station vessels have traditionally collected 

 the maximum amount of oceanographic data possible. These include 

 bathythermograph observations, plankton tows, and echo soundings. 



Lack of adequate instrumentation, however, has precluded any full- 

 scale observations. 



Prior to 1961, oceanographic work by the Coast Guard was 

 limited to the support of the Internationa] Ice Patrol, and what 

 could be accomplished on a cost free and not-to-interfere basis. 

 However, Public Law 397-87 was intended to bring the facilities and 

 capabilities of the Coast Guard into the National Oceanographic 

 effort. Along with this legislation, the Coast Guard, representing 

 the Treasury Department, became a member of the Interagency 

 Committee on Oceanography. 



To implement oceanographic observations from ocean station 

 vessels, one ship was outfitted in 1962 as a prototype and, to date, 

 has conducted a complete oceanographic program on two ocean 

 station cruises. These observations were made under the super- 

 vision of a team of U. S. Naval Oceanographic Office and Coast 

 Guard oceanographers. 



Based on the experience gained with the prototype ship, a con- 

 tinuing program is now underway for outfitting all major cutters 

 assigned to ocean station duties, so that a basic oceanographic 

 capability will be provided in all ships. In cooperation with the 

 U. S. Naval Oceanographic Office, and in addition to other oceano- 

 graphic instrumentation, these ships are being equipped with wave 

 recorders and electronic bathythermographs. Installation has com- 

 menced and will proceed at the rate of about one ship per month 

 over the next two and one-half years. 



POSITION-INDICATING GRID SYSTEM 



OCEAN STATION VESSELS 



Figure 1- Position indicating grid. 



NAVIGATIONAL AIDS 



Originally, an ocean "station" included the area within a 1(X)- 

 mile radius of an assigned control point. World War II proved this 

 impractical, and, consequently, this limit was discarded. After the 

 war, to assist weather ships in carrying out their mission as aids to 

 surface and air navigation, the "station" was changed to a grid 210 

 miles square. Figure 1. This grid is divided into 10-mile squares. 

 The purpose of the grid is to provide a device for the ocean station 

 vessel to indicate its position on her medium frequency radiobeacon. 

 The signal transmitted by the radiobeacon is a continuous carrier 

 wave with identifying letters superimposed on it. This signal con- 

 sists of four letters; the first 2 letters comprise the characteristic 

 signal of the station and the last 2 indicate its position within the 

 grid. If a ship is on station, i.e., within the 10-mile square at the 

 center, the last two letters of the signal are "OS", the latitude and 

 longitude designators, respectively. If the ship is outside the center 



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