4. Numerics# 4.1. Overview 4.2. Time Stepping 4.2.1. 3D momentum and tracers 4.2.2. Tracers-momentum coupling 4.2.3. Barotropic mode 4.2.4. Baroclinic-barotropic coupling 4.2.5. Stability constraints 4.3. Advection Schemes 4.3.1. Lateral Momentum Advection 4.3.2. Lateral Tracer advection 4.3.3. Vertical Momentum advection 4.3.4. Vertical Tracer advection 4.3.5. Adaptively implicit vertical advection 4.3.6. Numerical details on advection schemes 4.4. Pressure gradient 4.5. Equation of State 4.6. Wetting and Drying 4.7. Non-Boussinesq Solver