The ice of the Baltic Sea

Sea ice forms in the Baltic Sea annually, can be found there for seven months of the year, and has a very important role in the annual course of physical and ecological conditions in the basin. Therefore, a treatise on the Baltic Sea needs a chapter on ice, a topic that is usually less familiar to physical oceanographers. Section 7.1 introduces the ice season, and the following sections then progress from small to large scales. Section 7.2, for example, contains fine-scale questions and shows that brackish ice is structurally like normal sea ice; it also presents ice crystal structure, phase diagram, and sediments. Section 73 focuses on the small scale considering the growth and melting of sea ice, using analytical and numerical models. Section 74 looks at meso-scale and large-scale physics and introduces drift ice, its material structure, kinematics, and dynamics. Sea ice is a peculiar, granular, compressible, non-linear medium. Section 7.5 presents full sea ice models (i.e., basin-scale systems for the growth, drift, and decay of ice with vertical thermodynamics and horizontal dynamics).