Thermocline
A layer of water in the ocean where the temperature gradient, or the degree of inclination, is greater than that of the warmer layer above and the colder layer below. A zone where the temperature starts decreasing rapidly with depth.
Oscillation
The see-saw pattern of reversing surface air pressure between the eastern and western Pacific.
Upwelling
The upward motion of sub-surface water toward the surface of the ocean. This is often a source of cold, nutrient-rich water.
Cumulonimbus
A cloud type that is dense and vertically developed and is associated with rain.