Energy Transport in the Climate System and Its Parameterisation

Abstract

In the annual mean, the Earth takes up energy between 30∘ S and 30∘ N, while it has a negative energy balance towards the poles (Fig. 4.1). Since neither a continuous warming in the lower latitudes nor a cooling in the high latitudes are observed, a strong poleward transport of energy is required. The integration of the meridional radiation balance from the South Pole to the North Pole, as it is given in Fig. 4.1, yields the heat transport, required by the radiation balance (Fig. 4.2). In each hemisphere, about (Petawatt) are transported polewards. This flux is split about evenly between ocean and atmosphere. The maximum heat transport in the northern hemisphere occurs around 45∘ N in the atmosphere and around 20∘ N in the ocean. This fact points to the different mechanisms and boundary conditions (continents) responsible for the meridional heat transport. The atmosphere transports heat in a way fundamentally different from that of the ocean. The most important mechanisms are briefly explained in the following sections.