APHELION 



anomaly of dynamic height — See dynamic 

 height anomaly. 



anomaly of geopotential difference — See dy- 

 namic height anomaly. 



anomaly of specific volume — See specific vol- 

 ume anomaly. 



anoxemia — See anoxia. 



anoxia — (also called anoxemia) . The absence of 

 oxygen; an abnormal condition produced by 

 breathing air which is deficient in oxygen. (5) 



anstau — The process resulting in the piling up of 

 water, such as occurs in convergence. (14) 



antagonism — A relationship between species in 

 which at least one species is harmed. See anti- 

 biosis, parasitism. 



antarctic air — A type of air whose characteristics 

 are developed in an antarctic region. Antarctic 

 air appears to be colder at the surface in all sea- 

 sons, and at all levels in autumn and winter, than 

 artic air. (5) 



antarctic anticyclone — ( or antarctic high) . The 

 glacial anticyclone which has been said to over- 

 lie the continent of Antarctica ; analogous to the 

 Greenland anticyclone. (5) 



Antarctic Bottom Water — See v^ater mass. 



Antarctic Circumpolar Current — See West 

 Wind Drift. 



Antarctic Convergence — (or Antarctic Con- 

 vergence line, Antarctic Convergence zone). 

 The Southern Hemisphere polar convergence. 

 It is the best defined convergence line in the 

 oceans, being recognized by a relatively rapid 

 northward increase in the surface temperature. 

 It can be traced around the world in the broad 

 belt of open water between Antarctica to the 

 south and Africa, Australia, and South America 

 to the north. See convergence. 



Antarctic Convergence line — See Antarctic 

 Convergence. 



Antarctic Convergence zone — See Antarctic 

 Convergence. 



antarctic high — See antarctic anticyclone. 



Antarctic Intermediate Water — See water 

 mass. 



Antarctic Ocean — The name commonly applied to 

 those portions of the Atlantic, Pacific, and In- 

 dian Oceans which reach the Antaric Continent 

 on the south and are bounded on the north by 

 the Subtropical Convergence. This feature is 

 not a recognized ocean body. 



antecedent platform theory — A theory of coral 

 atoll and barrier reef formation which postu- 

 lates a submarine platform 50 meters or more 

 below sea level from which barrier reefs and 

 atolls grow upward to the water surface without 

 changes in sea level. (2) 



anthozoan — One of a class (Anthozoa) of coelen- 

 terates in which the medusoid stage is absent 

 and the polyp (hydroid) stage is better de- 

 veloped than in the other coelenterates. The 

 sea anemones, sea pens, and corals are some 

 members of this group. 



antibiosis — Tlie relationship between species in 

 wliich certain substances produced or excreted 

 by organisms are generally harmful to others. 

 The mass kills of fishes and other organisms due 

 to outbreaks of red tide are examples of anti- 

 biosis. 



anticline — A fold or arch of rock in which the 

 strata dip in opposite directions away from the 

 plane of the axis. See syncline. 



anticyclone — An atinospheric anticyclonic cir- 

 culation, a closed circulation. With respect to 

 tiie relative direction of its rotation, it is the 

 opposite of a cyclone. 



Because anticyclonic circulation and relative 

 high atmospheric pressure usually coexist, the 

 terms anticyclone and high are used inter- 

 changeably in common practice. (5) 



anticyclonic — Having a sense of rotation about 

 the local vertical opposite to that of the earth's 

 rotation; that is, clockwise in the Northern 

 Hemisphere, counterclockwise in the Southern 

 Hemisphere, undefined at the Equator. It is 

 the opposite of cyclonic. (5) 



antif ouling coating — See antifouling paint. 



antifouling paint — (or antifouling coating). A 

 substance applied to a surface to prevent the 

 attachment of fouling organisms when sub- 

 merged. The principle applied is the gradual 

 release of compounds toxic to fouling organisms; 

 effectiveness of the coating depends upon the 

 toxicity of the compound and the rate and 

 duration of release. Toxic compounds com- 

 monly used are cuprous oxide and mercuric 

 oxide. 



Antilles Current — A current formed by part of 

 the North Equatorial Current that flows along 

 the northern side of the Greater Antilles. The 

 Antilles Current joins the Florida Current 

 north of Grand Bahama Island to form the 

 Gulf Stream. 



antinode — See loop. 



Antisubmarine Warfare — (abbreviated ASW). 

 Operations conducted against submarines, their 

 supporting forces and operating bases. (63) 



Antisubmarine Warfare Environmental Pre- 

 diction System— (abbreviated ASWEPS). 

 An integrated system of men and machines to 

 predict and display oceanographic parameters 

 in support of antisubmarine warfare operations. 



antitrades — (formerly, also called counter- 

 trades) . A deep layer of westerly winds in the 

 troposphere above the surface trade winds of 

 the tropics. They comprise the equatorward 

 side of the mid-latitude westerlies, but are found 

 at upper levels rather than at the surface. 



The antitrades are best developed in the 

 winter hemisphere, and also above the eastern 

 extremities of the subtropical highs. (5) 



aperiodic motion — Any nonperiodic motion. 



aphelion — The point in the earth's orbit farthest 

 from the sun. (50) 



