The greater the change per unit of distance, the stronger the gradient, and the stronger the winds. Humidity See relative humidity. A measure of the water-vapor content of air. A state in which the vertical distribution of temperature is such that an air particle, if given either an upward or downward impulse, will tend to move away with increasing speed from its original level. Inversion An atmospheric layer where temperature increases with height in contrast to a normal decrease in temperature with height.
Inversion is more common under high pressure with clear skies and light winds.
Warm air above the surface of the ground acts as a lid, trapping colder air in low-lying valleys. Temperatures can be cooler in valleys under the inversion than higher elevated mountain slopes. An extended duration of inversion can lead to increased air pollution. Knot The unit used to measure wind speed, equal to 1.15 statute miles per hour. Unusually cold ocean temperatures in the tropical eastern Pacific waters near the coast of South America, typically felt in winter months with global weather impacts.