ALBEDOMETER . An instrument used for the measure- 

 ment of the reflecting power (the ALBEDO) of a 

 surface. A PYRANOMETER (see ACTINOMETER) adapted 

 for the measurement of radiation reflected from 

 the earth's surface is sometimes employed as an 

 albedometer. (24) 



ALEUTIAN CURREOT . An eastward flowing ocean cur- 

 rent which lies north of the NORTH PACIFIC CURRENT; 

 it is the northern branch of the KUROSHIO extension 

 which moves northeast then east between 40 N and 

 50°N. As it approaches the coast of North America 

 it divides to form the northward-flowing ALASKA 

 CURRENT, and the southward -flowing CALIFORNIA 

 CURRENT. (24) 



ALGAE . Marine, brackish, and fresh-water plants 

 (including marine seaweeds), ranging in size from 

 microscopic unicellular plants to the giant kelps. 

 Marine algae often have leaflike and stemlike parts 

 similar to those of terrestrial plants but differ 

 from them in cellular structure. (15) 



ALIMENTATION . Generally, the process of providing 

 nourishment or sustenance; thus in glaciology, the 

 combined processes which serve to increase the mass 

 of a glacier or snowfield; the opposite of ABLATION. 

 The deposition of snow is the major form of glacial 

 alimentation, but other forms of precipitation 

 along with sublimation, refreezing of melt water, 

 etc. also contribute. 



The additional mass produced by alimentation 

 is termed ACCUMULATION. (24) 



ALKALINITY . In sea water, the excess of hydroxyl 

 ions over hydrogen ions, generally expressed as 

 milliequivalents per liter. (24) 



ALPHA PARTICLE . Same as the helium atom nucleus, 

 containing two protons and two neutrons and pro- 

 duced or ejected by certain nuclear reactions or 

 rearrangements such as the decomposition of radium 

 and uranium. Each alpha particle has a double 

 positive charge and is spoken of collectively as 

 alpha radiation. (39) 



ALS . American Littoral Society. 



ALTERNATION OF GENERATIONS . Alternation of genera- 

 tions is the occurrence of two phases, or genera- 

 tions, in the life cycle of an organism which re- 

 produces sexually. One of these generations pro- 

 duces the spores and is called the SPOROPHYTE gener- 

 ation. The other, which produces the GAMETES, is 

 known as the GAMETOPHYTE generation. The word 

 generation refers here to the time interval between 

 the birth of the parents and that of the progeny. 

 (18) 



ALTOCUMULUS . A cloud layer (or patches) within the 

 middle level (mean height 6,500-20,000 feet) com- 

 posed of rather flattened globular masses, the 

 smallest elements of the regularly arranged layers 

 being fairly thin, with or without shading. These 

 elements are arranged in groups, in lines, or waves, 

 following one or two directions, and are sometimes 

 so close together that their edges join. (17) 



ALTOSTRATUS . A sheet of gray or bluish cloud with- 

 in the middle level (mean height 6,500-20,000 feet). 

 Sometimes the sheet is composed of a compact mass 

 of dark, thick, gray clouds of fibrous structure; 

 at other times the sheet is thin and through it the 

 sun or moon can be seen dimly as though gleaming 

 through ground glass . (17) 



ALUMINAUT . An aluminum hulled submarine presently 

 under construction by the Electric Boat Division 

 of General Djmamics Corp. It is designed for 

 oceanographic research, will be 50 feet in length, 

 and have a maximum cruising depth of 15,000 feet. 



ALUVIUM . Soil (sand, mud, or similar detrital 

 material) deposited by flowing water, or the 

 deposits formed thereby. (10) 



ALVEOLAR EXCHANGE . The transposition of oxygen to 

 the blood and the removal of carbon dioxide in the 

 alveolae of the lungs. (37) 



ALVEOLI . The lungs can be thought of as two 

 elastic bags containing millions of little dis- 

 tensible air sacs. These air sacs or alveoli 

 are all connected to the air passages, which 

 branch and rebranch like the twigs of a tree. (37) 



ALVIN. A manned submersible vehicle (USA). See 

 Appendix Chart. 



AM. U. S. Navy designation for a Minesweeper. 



AMBIENT NOISE . The composite noise from all sources 

 in a given environment excluding the desired signal 

 and noise inherent in the measuring equipment and 

 platform. 



AMCU. U. S. Navy designation for Underwater 

 Locator. 



AMERICAN SUBMARINE MODEL 600 . A manned submersible 

 vehicle (US). 



AMMETER . An instrument for measuring the electron 

 flow in amperes. (36) 



AMOS. 



Acoustic Meteorological Oceanographic Survey. 



AMPERE . The basic unit of current flow; a current 

 of one ampere- V7ill flow through a conductor having 

 a resistance of one ohm when a potential of one 

 volt is applied. (36) 



AMPHIDROMIC POINT . A point on a chart of COTIDAL 

 LINES from which the cotidal lines radiate. (24) 



AMPHIDROMIC REGION . An oceanic region whose 

 COTIDAL LINES radiate from one AMPHIDROMIC POINT. 

 (24) 



AMPHITRITE . The name of a 65 foot long, 6 ton in- 

 flatable ship used as a tender in sea diving 

 operations . 



AMPLIDYNE . A type of dc generator used as a power 

 amplifier, (output voltage responds to changes in 

 field excitation) . 



AMPLITUDE . 1. The semirange of a CONSTITUENT tide. 

 By analogy, it may be applied also to the maximum 

 velocity of a constituent current. (14) 



2. In hydrodynamics, one-half the wave height. 



3. In engineering usage, loosely, the wave 

 height from crest to trough. (10) 



AMS . American Meteorological Society. 



AMS . U. S. Navy designation for a Minesweeper, 

 Coastal. 



AMSFC . Atlantic States Marine Fisheries Commission, 

 AN . U. S. Navy designation for a Net Laying Ship. 



ANCHORAGE BUOY . One of a series of buoys marking 

 the limits of an anchorage. A buoy marking the 

 location of a quarantine anchorage is called a 

 quarantine buoy. (17) 



ANCHOR BUOY . A buoy marking the position of an 

 anchor. (17) 



ANEMOMETER . The general name for instruments 



