I ICAO—Abbreviation for International Civil Aviation Organization. ICEBERG—Ice   found   floating   in   the   sea   that originated from glaciers formed from freshwater accumulations  of  snow. IFR—Abbreviation for instrument flight rules. INFRARED (IR)—The portion of the electromagnetic spectrum with wavelengths just slightly longer than visible light energy (heat energy). INVERSION—With   respect   to   temperature,   an increase in temperature with height. Normally, temperature   decreases   with   height   in   the atmosphere. IRCS—lntemational  radio  call  sign. ISOTHERMAL —Having    an    equal    temperature throughout. K kn—Alternate  abbreviation  for  knot.  In  meteorology, the more frequently used abbreviation is "kt," but this  should  not  be  confused  with  the  uppercase "KT" meaning kiloton. L LAN—Local area network. LAPSE RATE—The  decrease  of  an  atmospheric variable  with  height;  the  variable  being  temperature unless  otherwise  specified. LCD—Liquid crystal display. A gray or black display of   numbers   or   shapes   commonly   used   in electronics. LDATS—Lightning  Detection  and  Tracking  System. LEWP—A radar feature, the line echo wave pattern, normally an indicator of severe weather. LITTORAL—The coastal zone including the beach to the coastal waters. LLWS—Low--level  wind  shear. LOW—An "area of low pressure" in the horizontal plane referring to the isobars on a surface chart, or an "area of low heights," in the vertical plane referring to the height contours on a constant pressure  chart. M MANOP—Formatted weather message header that identifies the product type, originator, and area covered by the product. MET—U.S.  Navy  mobile  environmental  team. METEM   TECHNICIAN—A meteorological electronic  equipment  maintenance  technician,  a term usually referring to a Navy ET who has received   special   training   on   meteorological equipment in the METEM school. METEOROLOGY —The study of phenomenon of the atmosphere. METVANS—USMC  mobile  meteorological  vans. Highly   transportable,   completely   equipped meteorological facilities constructed as complete modules  in  cargo  containers.  Modules  may  be  used independently  or  connected  to  form  complete,  full-- spectrum, meteorological support facilities in a forward  deployed  environment. MILS—An angular measurement scale in which 800 mils equals 45 degrees of arc; a circle is 6,400 mils. MMF—U.S. Marine Corps mobile meteorological force (weather personnel who operate USMC Metvans). MRC—Abbreviation  for  maintenance  requirements card used with the 3-M System. MRS—Mini rawinsonde system. MSL—Mean sea level, a suffix used after altitude measurements. MVFR—Marginal visual flight rules. N NATO—North  Atlantic  Treaty  Organization. NAVMETOCCOM—Short title for Naval Meteorology  and  Oceanography  Command headquartered   at   the   Stennis   Space   Center, Mississippi. NBC—An   acronym   for   nuclear,   biological,   or chemical. NDASI—Navy digital altimeter setting indicator, also DASI. NDB—Nondirectional   beacon;   a   radio   aircraft navigation aid that allows aircraft to determine the direction of the transmitter. AI-3