Category: Define

Ionosphere A complex atmospheric zone of ionized gases that extends between 50 and 400 miles (80 to 640 kilometers) above the earth’s surface. It is

Isobar The line drawn on a weather map connecting points of equal barometric pressure. Barometric Pressure The pressure exerted by the atmosphere at a given

Isotherm The line of equal or constant air temperature. If something is isothermal, it is of equal or constant temperature with respect to either time

Jet Stream An area of strong winds that are concentrated in a relatively narrow band in the upper troposphere of the middle latitudes and subtropical

Kelvin Temperature Scale A temperature scale with the freezing point of +273°K (Kelvin) and the boiling point of +373° K. It is used primarily for

Knot A nautical unit of speed equal to the velocity at which one nautical mile is traveled in one hour. Used primarily by marine interests

Land Breeze A diurnal coastal breeze that blows offshore, from the land to the sea. It is caused by the temperature difference when the sea

Landfall The point at which a tropical cyclone’s eye first crosses a land mass. Tropical Cyclone A warm core low pressure system which develops over

Landspout A small, weak tornado, which is not formed by a storm-scale rotation. It is generally weaker than a supercell tornado and is not associated

Latent Heat The energy released or absorbed during a change of state.