Introduction

This module contains the definitions of the most important mean flow variables used in geophysical models. In GOTM, these are

• the mean horizontal velocity components, $U$ and $V$
• the mean potential temperature, $\Theta$, (or the mean buoyancy, $B$)
• the mean salinity, $S$

Note that in general a variable $\phi$ describing a turbulent field can be decomposed into a mean and a fluctuating part. In GOTM, we use the notation

$$\phi = {\langle \phi \rangle} + \phi' \; , \quad$$ (1)

where ${\langle \rule{3mm}{0mm} \rangle}$ denotes the ensemble mean and the prime the fluctuating part. In addition, for brevity, we use the following conventions:

$$\begin{array}{rcl} U &=& {\langle u \rangle} \quad \text{for ... ...& {\langle s \rangle} \quad \text{for the salinity} \end{array}$$ (2)

Note that, if not explicitly mentioned, GOTM uses the units kg, m, s, K. Further conventions are introduced in the turbulence chapter section 4. All operations on these meanflow variables are executed and coordinated in the meanflow module.