GEG-1 Lecture Notes - Lecture 28: Cloud Seeding, Cool Air, Dew Point
Document Summary
Humidity is a measure of water vapor in the air. Absolute humidity- mass of water per cubic meter of air. Maximum amount air can hold depends on air temp. warmer air can hold more air. Since max amount is in denominator, rh inversely proportional. Temp at which air becomes saturated with water vapor. Air becomes saturated either by adding more water to the air or by cooling the air. Cool air below dew point = condensation. Fog cloud at ground surface, mostly caused by diabatic processes. Radiation fog night cooling of ground surface, air above cools. Advection fog warm, moist air moves over cooler surface (coasts). Adiabatic processes cooling not by removing energy, but changing the volume of air. Recall environmental lapse air above is cooler because of lower pressure (not. Dry adiabatic lapse rate rising air cools at about -10 degrees /1000m, until saturation; lower pressure- larger volume- lower temp.
