Physical Geography
Oceanography
Oceanography is the interdisciplinary study of Earth’s global ocean, encompassing its physical dynamics, chemical composition, geological structures, and biological systems. The field integrates shipboard surveys, autonomous observing networks, satellite remote sensing, laboratory analyses, and numerical modeling to understand circulation, climate regulation, ecosystems, and the seafloor. Contemporary oceanography addresses issues such as ocean warming, sea-level rise, ocean acidification, deoxygenation, and mapping of the largely unexplored seabed.
Thermohaline circulation
Thermohaline circulation (THC) is the global-scale component of ocean circulation driven by density gradients set by seawater temperature and salinity. It links surface and deep layers through high‑latitude sinking and widespread upwelling, transporting heat, freshwater, nutrients, and carbon and shaping regional and global climate. Modern observing arrays and paleoclimate evidence show its variability across years to millennia, with a very likely weakening projected under continued warming.