EARTH 10 Lecture Notes - Lecture 3: Antarctic Circumpolar Current, Downwelling, Upwelling
Document Summary
Thermohaline ocean circulation : driven by global density gradients created by surface heat and freshwater fluxes. Sea-ice formation extracts freshwater, increases salinity and density, causes water to sink. Aa bottom water: deepest water masses in oceans, forms on shelf as sea-ice freezes, including salinities. Aa circumpolar waters: mixing of aa deep waters with warmer north waters. Aa intermediate water: forms north of aa circumpolar current, most widespread intermediate water in the world"s oceans fronts: where different water masses meet polar - 50 subaa - 45 subtropical - 40. Convergence (come together) and divergence (grow apart) of ocean masses leads to upwelling/divergence. Upwelling vs. downwelling important for nutrients in the ocean between antarctic circumpolar current and aa coastal current. Most from the sun (93 million miles/150km away), small fraction from earth"s interior, unbalanced due to tilt tropics have equal energy all year, poles have 6/6 split. Albedo: reflecting solar energy, highest with white, 80% of energy coming to aa"s reflected back.
