ARCTIC WHITEOUT . A peculiar condition affecting 

 visibility caused by a snow cover obliterating all 

 landmarks and accompanied by an overcast sky or 

 cirrostratus and/or altostratus clouds. No shadows 

 are cast and the picture is one of an unrelieved 

 expanse of white. Earth and sky blend so that the 

 horizon is not distinguishable. This condition is 

 extremely dangerous to low-flying aircraft, particu- 

 larly those attempting to land. Pilots have well 

 described the condition as "like flying in a bowl 

 of milk." An analogous condition in the antarctic 

 regions is called an Antarctic whiteout. (25) 



ARD . U. S. Navy designation for a Floating Dry- 

 dock. 



ARC . U. S. Navy designation for an Internal Com- 

 bustion Engine Repair Ship. 



ARGILLACEOUS . Containing clay particles or of the 

 nature of clay. (27) 



ARGUS ISLAND . An oceanographic observation tower 

 located in 194 feet of water on Plantagenet Bank 

 some 25 miles southwest of Bermuda. 



ARL . U. S. Navy designation for a Landing Craft 

 Repair Ship. 



ARM . An inlet. The term is usually used in con- 

 nection with the larger body of water of which 

 it is a part, as an arm of the sea. (17) 



ARPA. Advanced Research Projects Agency. 



ARS . U. S. Navy designation for a Salvage Ship. 



ARSD . U. S. Navy designation for a Salvage Lifting 

 Vessel. 



ARST. U. S. Navy designation for a Salvage Craft 

 Tender. 



ARTHUR REMOTE-INDICATING THERMOMETER , 

 consists essentially of a plexiglass 

 containing the bridge circuit and a s 

 The two are connected by a two-conduc 

 weight plastic cable. It is used in 

 lar to the casting thermometer except 

 not fitted with a float to hold the s 

 at the water surface. The cable is i 

 meters and fractions, permitting the 

 to examine vertical distribution of t 

 (30) 



This device 

 indicator case 

 ensing unit, 

 tor light- 

 a manner simi- 



that it is 

 ensing unit 

 arked in 

 investigator 

 emperature. 



ARTIFICIAL NOURISHMENT . The process of replenish- 

 ing a BEACH by artificial means, e.g. by the 

 deposition of dredged material. (11) 



ARV. U. S. Navy designation for an Aircraft Repair 

 Ship. 



ARVA. U. S. Navy designation for an Aircraft 

 Repair Ship (Aircraft) . 



ARVE . U. S. Navy designation for an Aircraft 

 Repair Ship (Engine) . 



AS. U. S. Navy designation for a Submarine Tender. 



ASA . American Shellfisheries Association. 



ASCENDENT . See GRADIENT. 



ASCIDIAN . See TUNICATES . 



A-SCOPE . A Cathode Ray Oscilloscope indicator 

 depicting echo intensities by vertical deflections, 

 and ranges by the position of these deflections on 

 the horizontal trace. (7) 



ASDEFORLANT . Antisubmarine Defense Force, Atlantic 



Fleet. U. S. Naval Base, Norfolk, Virginia. 

 ASDEFORPAC . See COMASWEOHPAC . 



ASDIC . British echo-ranging equipment. Letters 

 derived from Antt-Submarine Development Investiga- 

 tion Committee. 



ASEXUAL . Any reproductive process which does not 

 involve the union of GAMETES. (18) 



AS HERA . A manned submersible vehicle (U.S.). 



AS IRC . Aquatic Sciences Information Retrieval 

 Center. 



AS LP . American Society of Limnology and Oceanogra- 

 phy. 



ASNE. American Society of Naval Engineers. 



ASP . American Society on Photogrammetry. 



ASPECT . The angle made by a target with the line 

 joining it to the observation point is known as the 

 aspect of the target. (4) 



ASR. U. S. Navy designation for a Submarine Rescue 

 Vessel. Also ASR means Air-Sea-Rescue Operations. 



AS ROC . (Contraction of antisubmarine rocket) . 

 A 1,000 lb rocket homing torpedo as well as an 

 integrated system composed of acoustical under- 

 water detection gear, fire control computer, and 

 a launcher holding eight missiles which are com- 

 binations of missiles, torpedoes, depth charges 

 and sonars . 



ASSA . U. S. Navy designation for a Cargo Submarine. 



ASSP . U. S. Navy designation for a Transport Sub- 

 marine. 



ASTIA . Armed Services Technical Information 

 Administration. Now called Defense Documentation 

 Center (DDC) . 



ASTM . American Society for Testing Materials. 

 AS TOR . A nuclear torpedo. 



ASTRONOMICAL TIME . Time formerly used in astro- 

 nomical calculations in which the day began at noon 

 rather than midnight. The astronomical day com- 

 menced at noon of the CIVIL DAY of the same date. 

 The hours of the day were numbered consecutively 

 from (noon) to 23 (11 a. m. of the following morn- 

 ing) . Up to the close of the year 1924 astronomi- 

 cal time was in general use in nautical almanacs . 

 Beginning with the year 1925 the American Ephemeris 

 and Nautical Almanac and similar publications of 

 other countries abandoned the old astronomical time 

 and adopted GREENWICH CIVIL TIME for the data given 

 in their tables. (14) 



ASW. Ant i -Submarine Warfare. 



ASWEPS . Anti-Submarine Warfare Environmental 

 Prediction System. 



ASWTNS . ASW Tactical Navigation System. 



ATA . U. S. Navy designation for an Auxiliary 

 Ocean Tug. 



ATF. U. S. Navy designation for a Fleet Ocean Tug. 



ATMOSPHERE . The envelope of AIR surrounding the 

 earth and bound to it more or less permanently by 

 virtue of the earth's gravitational attraction; the 



