This users guide provides documentation for the Princeton Ocean Model (POM), a three-dimensional numerical ocean model developed by Alan Blumberg and George L. Mellor around 1977. The model has been further developed by several researchers, including Leo Oey, Jim Herring, Lakshmi Kantha, and Boris Galperin. Recent contributions include work by Tal Ezer, who has been instrumental in research and user support. The model is used for simulating ocean dynamics, including turbulence, vertical mixing, and boundary layer processes. The POM is a sigma-coordinate model, meaning the vertical coordinate is scaled on the water column depth. It uses curvilinear orthogonal coordinates and an "Arakawa C" differencing scheme. The model includes a turbulence closure sub-model based on the Mellor-Yamada turbulence closure model, which is used to simulate mixed layer dynamics. The model also includes a free surface and a split time step, with the external mode being two-dimensional and the internal mode three-dimensional. The model has been updated over time, with changes in variable names and numerical schemes. The current version, pom2k.f, is written in standard FORTRAN 77 and includes a variety of subroutines for solving the basic equations, including advective, diffusive, and pressure gradient terms. The model supports both diagnostic and dynamic modes, with the diagnostic mode allowing for invariant thermodynamic properties over time. The model is used for a wide range of applications, including simulating coastal circulation, tidal estuaries, and deep ocean basins. It has been applied to various oceanographic problems and has been supported by numerous sponsors, including the Geophysical Fluid Dynamics Laboratory, Princeton University, and the Department of Energy. The model includes a variety of subroutines for solving the basic equations, including the calculation of baroclinic integrals, turbulence closure, and vertical diffusivity. The model also includes a variety of boundary conditions, including open boundary conditions, which are essential for regional models. The model is available online and can be accessed via FTP or the POM web page. The model is designed to handle significant topographical variability and includes a turbulence closure sub-model that provides vertical mixing coefficients. The model is used to simulate the flow across a seamount with prescribed vertical temperature stratification, constant salinity, and zero surface heat and salinity flux. The model is also used to simulate the flow through a channel with an island or seamount at the center of the domain. The model includes a variety of subroutines for solving the basic equations, including the calculation of advective terms, diffusive terms, and pressure gradient terms. The model is used to simulate the dynamics of coastal circulation, including fast-moving external gravity waves and slow-moving internal gravity waves. The model is designed to separate the vertically integrated equations (external mode) from the vertical structure equations (internal mode), allowing for efficient computation. The model includes a varietyThis users guide provides documentation for the Princeton Ocean Model (POM), a three-dimensional numerical ocean model developed by Alan Blumberg and George L. Mellor around 1977. The model has been further developed by several researchers, including Leo Oey, Jim Herring, Lakshmi Kantha, and Boris Galperin. Recent contributions include work by Tal Ezer, who has been instrumental in research and user support. The model is used for simulating ocean dynamics, including turbulence, vertical mixing, and boundary layer processes. The POM is a sigma-coordinate model, meaning the vertical coordinate is scaled on the water column depth. It uses curvilinear orthogonal coordinates and an "Arakawa C" differencing scheme. The model includes a turbulence closure sub-model based on the Mellor-Yamada turbulence closure model, which is used to simulate mixed layer dynamics. The model also includes a free surface and a split time step, with the external mode being two-dimensional and the internal mode three-dimensional. The model has been updated over time, with changes in variable names and numerical schemes. The current version, pom2k.f, is written in standard FORTRAN 77 and includes a variety of subroutines for solving the basic equations, including advective, diffusive, and pressure gradient terms. The model supports both diagnostic and dynamic modes, with the diagnostic mode allowing for invariant thermodynamic properties over time. The model is used for a wide range of applications, including simulating coastal circulation, tidal estuaries, and deep ocean basins. It has been applied to various oceanographic problems and has been supported by numerous sponsors, including the Geophysical Fluid Dynamics Laboratory, Princeton University, and the Department of Energy. The model includes a variety of subroutines for solving the basic equations, including the calculation of baroclinic integrals, turbulence closure, and vertical diffusivity. The model also includes a variety of boundary conditions, including open boundary conditions, which are essential for regional models. The model is available online and can be accessed via FTP or the POM web page. The model is designed to handle significant topographical variability and includes a turbulence closure sub-model that provides vertical mixing coefficients. The model is used to simulate the flow across a seamount with prescribed vertical temperature stratification, constant salinity, and zero surface heat and salinity flux. The model is also used to simulate the flow through a channel with an island or seamount at the center of the domain. The model includes a variety of subroutines for solving the basic equations, including the calculation of advective terms, diffusive terms, and pressure gradient terms. The model is used to simulate the dynamics of coastal circulation, including fast-moving external gravity waves and slow-moving internal gravity waves. The model is designed to separate the vertically integrated equations (external mode) from the vertical structure equations (internal mode), allowing for efficient computation. The model includes a variety