Contents

Chapter 3Basics of Geophysical Fluid DynamicsAbstract This chapter introduces the reader to scalars and vectors, Newton’s lawsof motion, waves and steady-state f ows, the buoyancy force, the Coriolis force, anumber of conservation principles, turbulence, and, finall , to the Navier–Stokesequations of flui motion. Practical exercises focus on the interference of waves,movement of a buoyant object in a stratifie water column, and movement of objectsunder the sole influenc of the Coriolis force.3.1 UnitsThe International System of Units will be used in most instances. Distances areexpressed in metres (m), time lapse in seconds (s), and mass in kilograms (kg).For convenience, temperatures are expressed in degrees Celsius ( ◦ C), which is thethermodynamic temperature in Kelvin (K) plus a constant of 273.16. Time lapse istranslated into more convenient units such as minutes, hours, days, weeks, months,years, etc. Other units can be derived from the above base units. For example, volumeis expressed in cubic metres (m 3 ). Often, we also use symbols for multiplierssuch as:micro (μ) = 10 −6 = 0.00001milli (m) = 10 −3 = 0.001centi (c) = 10 −2 = 0.01kilo (k) = 10 3 = 10003.2 Scalars and Vectors3.2.1 Difference Between Scalars and VectorsA scalar is a physical quantity without directional information. Temperature andpressure are examples of this. A vector, on the other hand, carries information ofboth magnitude and direction. Velocity is an example of this. A car moves at acertain speed into a certain direction.J. Kämpf, Ocean Modelling for Beginners,DOI 10.1007/978-3-642-00820-7 3, C○ Springer-Verlag Berlin Heidelberg 200917