ABSTRACT
Wind results from expansion and convection of air as solar radiation is absorbed on earth. On a global scale these thermal effects combine with dynamic effects from the earth's rotation to produce prevailing wind patterns (Fig. 9.1). In addition to this general or synoptic behavior of the atmosphere there is important local variation caused by geographical and environmental factors. Wind velocities increase with height, and the horizontal components are significantly greater than the vertical components. The latter are however important in causing gusts and short term variations. The kinetic energy stored in the winds is about 0.7 × 1021 J, and this is dissipated by friction, mainly in the air but also by contact with the ground and the sea. About 1% of absorbed solar radiation, 1200 TW (1200 × 1012 W), is dissipated in this way (refer to Fig. 1.2).
