Chapter 6: Physical Oceanography
Paul Webb
Learning Objectives
After reading this chapter you should be able to:
- explain the relationship between depth and pressure
- define the terms thermocline, pycnocline, and mixed layer
- recreate and describe temperature profiles for different regions of the ocean
- explain how density is related to temperature, pressure, and salinity
- explain how density changes with depth and latitude
- explain how sound travels through water, and what physical factors impact sound transmission
- define the concept of the SOFAR channel
- describe the behavior of light as it penetrates through ocean water
Picture yourself swimming in the ocean. Are you imaging frolicking in warm, crystal-clear water? Well scrap that idea, as that idyllic setting represents the conditions in only a tiny portion of the global ocean. The conditions in the vast majority of the ocean are nothing like those at the surface; most of the ocean is very cold, dark, and subjected to crushing pressures. However, even in those hostile conditions, there is a great diversity of organisms managing to make a living at depth. This chapter examines the physical environment of the ocean, including processes that are important for marine life, such as temperature, and light and sound transmission. The field of physical oceanography typically also includes the fluid properties of ocean water, such as waves, tides, and circulation. Those topics will be addressed in subsequent chapters.
