Comparison of Two Navy Environmental Database Models: Generalized Digital Environmental Model and Podeszwa Sound Speed Profile Model.

摘要

We review the construction of the Generalized Digital Environmental Model (GDEM), the Navy standard for modeling sound speed profiles, and the Podeszwa sound speed profile model which has been used by the Naval Underwater Systems Center. GDEM, developed by the Naval Oceanographic Office, derives vertical profiles of temperature and salinity in 30'x30' latitude-longitude grid elements and employs these data to calculate sound speed profiles. The temperature-salinity profiles are derived from quality-screened data from the Master Oceanographic Observation Data Set maintained by the Fleet Numerical Oceanography Center. Podeszwa uses temperature-salinity data from deep Nansen casts and organizes the calculated SSPs into provinces based on temperature-salinity water mass characteristics. In spite of the differences in their construction, the models are found to be essentially equivalent in principle. (kt)