into  the  Global  Command  and  Communications System-Maritime  (GCCS-M),  which  was  discussed  in chapter  one.  Information  describing  the  status  of  all GFMPL   environmental   programs   and   software versions is contained in the Geophysics Fleet Mission Program  Library  (GFMPL)  Summary,  also published by NAVO. Both the NT and PC versions of GFMPL are released as either unclassified or classified CD-ROMs. The classified GFMPL CD-ROMs contain detailed electromagnetic  and  acoustic  models  and  data  bases. GFMPL FUNCTIONS GFMPL   is   a   rapid-response,   on-scene, environmental  prediction  system  used  to  quickly determine the effects of the environment on fleet platforms,  sensors,  and  weapon  systems.  Locally collected environmental information is used to prepare analyses of present atmospheric and electromagnetic (EM)   propagation   conditions.   Locally   collected oceanographic information is combined with archived data to prepare an analysis of existing oceanographic and acoustic conditions. Analyses and predictions are based upon on-scene data, historical data, platform characteristics, and weapon/sensor characteristics. GFMPL comprises four basic functions as described below. Environmental Data Assimilation GFMPL  accepts  locally  acquired  environmental data from various sources, catalogs and processes the data, and then writes the data to available files for use by the various programs. This data includes operator- entered   surface,   radiosonde,   refractivity, bathythermograph,  and  nearshore  bathymetry  data. This function also incorporates quality control checks of environmental data input. Environmental  Analysis GFMPL   generates   analyses   of   existing environmental   conditions   affecting   air,   surface, amphibious, and USW operations. These analyses are provided  by  atmospheric,  meteorological,  and oceanographic  application  programs.  The  analyzed data is presented in the form of graphic and tabular displays, which can also be hardcopied and used for performance predictions and briefings. Sensor Detection Range/Coverage Prediction GFMPL  computes  acoustic  and  electromagnetic (EM) sensor range predictions based on oceanographic 2-4 and meteorological environmental profiles. Output is used for detection/counter detection of threat/force platforms. Platform and sensor data base parameters can  be  modified  as  necessary  (both  acoustic  and atmospheric). Output is provided in either spreadsheet, graphical, or tabular format. Data File Maintenance This function provides the capability to create, maintain, and/or delete data files. This function also ensures the integrity of the data files and provides adequate  safeguards  for  any  classified  information  in the files. GFMPL PROGRAMS There  are  numerous  environmental  software programs  available  from  GFMPL,  and  each  version comes loaded with a different suite of programs. The environmental  programs  provided  with  GFMPL  NT can be divided into seven broad categories, which are summarized  below: Environment—This option contains general programs,   such   as   Historical   Electromagnetic Propagation  Conditions  (HEPC)  and  Propagation Conditions Summary (PCS). It also contains an ocean Sound Speed Profile (SSP) program. Meteorology—This  option  contains  programs that  calculate  pressure  altitude  and  density  altitude  data, wind chill and heat stress values, and astronomical data (sunrise, lunar illumination, civil twilight, etc.). Electromagnetics—This   option   contains programs that predict radar performance and calculate radar  ranges.  Electromagnetic  programs  include surface-search radar range predictions and electronic countermeasure effectiveness displays. Electromagnetic  path-loss  curves  and  radar  coverage diagrams can also be produced. Oceanography—This  option  contains  programs such as the Tidal Prediction and Analysis (TIDES), Surf Forecasting (SURF), and Beach Survey Chart (BSC). The BSC program allows for the creation, display, and editing of a digital beach chart as surveyed by Special Forces  personnel. Acoustic—The  Acoustic  option  contains  the Generic Acoustic Prediction (GAP) program and the Tactical Oceanographic/Acoustic Spreadsheet (TOAS) program. GAP is used to produce horizontal contours of ocean temperature, sound speed, and salinity. It also