This document is a user guide for a three-dimensional, primitive equation, numerical ocean model developed by George L. Mellor and Alan Blumberg around 1977. The model, known as the Princeton Ocean Model (POM), is widely used for simulating ocean dynamics and has been updated over the years to incorporate various improvements and changes. The guide covers the model's structure, equations, numerical scheme, and subroutines, including those for external and internal modes, boundary conditions, and turbulence closure. Key features of the model include: - **Equations**: The model uses a bottom-following, sigma coordinate system to handle topographical variability and simulate realistic bottom boundary layers. - **Turbulence Closure**: The Mellor-Yamada turbulence closure model is embedded to provide vertical mixing coefficients, which are crucial for simulating mixed layer dynamics. - **Numerical Scheme**: The model employs a staggered grid arrangement and a leapfrog time-stepping scheme to handle advection and diffusion terms accurately. - **Subroutines**: Detailed descriptions of subroutines such as `advct`, `proft`, `bcond`, and `advq` are provided, explaining their roles in solving momentum, thermal, and other transport equations. - **Boundary Conditions**: The model supports various boundary conditions, including open boundary conditions for regional models, which are discussed in detail in section 16. - **Time Stepping**: The guide explains the time step constraints for both the external and internal modes, emphasizing the importance of CFL stability conditions. The document also acknowledges the contributions of various researchers and sponsors who have supported the development and application of the model over the years.This document is a user guide for a three-dimensional, primitive equation, numerical ocean model developed by George L. Mellor and Alan Blumberg around 1977. The model, known as the Princeton Ocean Model (POM), is widely used for simulating ocean dynamics and has been updated over the years to incorporate various improvements and changes. The guide covers the model's structure, equations, numerical scheme, and subroutines, including those for external and internal modes, boundary conditions, and turbulence closure. Key features of the model include: - **Equations**: The model uses a bottom-following, sigma coordinate system to handle topographical variability and simulate realistic bottom boundary layers. - **Turbulence Closure**: The Mellor-Yamada turbulence closure model is embedded to provide vertical mixing coefficients, which are crucial for simulating mixed layer dynamics. - **Numerical Scheme**: The model employs a staggered grid arrangement and a leapfrog time-stepping scheme to handle advection and diffusion terms accurately. - **Subroutines**: Detailed descriptions of subroutines such as `advct`, `proft`, `bcond`, and `advq` are provided, explaining their roles in solving momentum, thermal, and other transport equations. - **Boundary Conditions**: The model supports various boundary conditions, including open boundary conditions for regional models, which are discussed in detail in section 16. - **Time Stepping**: The guide explains the time step constraints for both the external and internal modes, emphasizing the importance of CFL stability conditions. The document also acknowledges the contributions of various researchers and sponsors who have supported the development and application of the model over the years.