FUNNEL SEA 



variable. It may be presented as a liistoffram, 

 frequency curve, rose, or other graphic form. 



frequency of set — The number of observations 

 sliowing a current set in a particuhir direction. 

 It is expressed as a percentage of the total ob- 

 servations in a specific area or location. 



frequency of sound — The number of sound waves 

 passing a jDoint in a given time; usually meas- 

 ured as cycles per second. 



freshet — An area of comparatively fresh water 

 at or near the mouth of a stream flowing into the 

 sea. (68) 



fresh ice — 1. Ice formed on fresh water. 



2. Young ice of any kind. 



3. Ice that has been salty but is now free of 

 salt. 



(59) 

 fresh water — AVater contammg no signincant 



amounts of salts, such as in rivers and lakes, 



as contrasted with sea water. 



f rictional drag — See intrainment force. 



frictional layer — The layer of the ocean which 

 is affected by wind action. 



friction factor — The wave height reduction factor 

 due to friction (along the bottom) alone. (10) 



friendly ice — From the point of view of the sub- 

 mariner, an ice canopy containing many large 

 ice skylights or other features which permit 

 the submarine to surface. (7) 



fringing reef — A reef attached directly to the 

 shore of an island or continental landmass. Its 

 outer margin is submerged and often consists 

 of algal limestone, coral rock, and living coral. 



frith — See firth, also estuary. 



frond — See lamina. 



front — 1. In meteorology, generally, the interface 

 or transition zone between two air masses of 

 different density. Since the temperature dis- 

 tribution is the most important regulator of 

 atmospheric density, a front almost invariably 

 separates air masses of different temperature. 



2. See ice front, convergence. 

 (5) 



front bay — A large irregular bay connected with 

 the sea through passes between barrier islands. 

 (2) 



front of the fetch — The end of the generating 

 ai'ea toward wliich the wind is blowmg. (61) 



frost columns of ice — See candle ice. 



frost smoke — 1. (sometimes called harber) . Fog- 

 like clouds, due to the contact of cold air with 

 relatively warm sea water, which appear over 

 newly-formed leads (lanes) and pools or lee- 

 ward of the ice-edge. These clouds may persist 

 while slush or sludge and young ice are 

 forming. (74) 

 2. See steam fog. 



frustule — The siliceous shell of a diatom, con- 

 sisting of two valves, one overlapping the 

 other. It is the principal constituent of marine 

 diatomaceous ooze. (2) 



fulls — See beach ridge. 



fully-arisen sea — See fully-developed sea. 



fully-developed sea — (also called fully-aruen 

 sea). The maximum height to which ocean 

 waves can be generated by a given wind force 

 blowing over sufficient fetch, regardless of 

 duration, as a result of all possible wave com- 

 ponents in the spectrum being present with their 

 maximum amount of spectral energy. 



fundamental unit — A unit measure of basic phys- 

 ical quantity such as mass, length, time; for 

 example, one gram, one centimeter, one second, 

 respectively. Other quantities such as force, 

 temperature, etc., may be considered funda- 

 mental and each assigned a fundamental unit. 



(5) 



fungus — (or mold). A thallophj^te lacking 

 chlorophyll. Many marine fungi have been 

 identified. Some are believed to add to the 

 damage caused by marine borers by penetrating 

 the wood around burrows of the borers. 



funnel sea — A gulf or bay, narrow at its head 

 and wide at its mouth and deepening rapidly 

 from head to mouth. (2) 



67 



