Science / Weather / Density Altitude: The altitude at which a given density is found in the standard atmosphere. Used in aviation, it is computed from the station pressure at takeoff and the virtual temperature at the particular altitude MORE
Science / Weather / Pressure Altitude: The altitude in standard atmosphere at which a given pressure will be observed. It is the indicated altitude of a pressure altimeter at an altitude setting of 29.92 inches of mercury, and is therefore MORE
Technology / Aviation / Absolute Altitude: The measureable height of an aircraft above the actual terrain. MORE
Science / Weather / Subtropical Jet: Marked by a concentration of isotherms and vertical shear, this jet is the boundary between the subtropical air and the tropical air. It is found approximately between 25?° and 35?° North latitude a MORE
Science / Weather / Mean Sea Level: The average height of the sea surface water level. For the United States, it is computed by averaging the levels of all tide stages over a nineteen year period, determined from hourly height readings MORE
Science / Weather / Melting Level: The altitude at which ice crystals and snow flakes melt as they descend through the atmosphere. MORE