METEOROLOGY. GEL-1370. Chapter Five. Cloud Development & Precipitation. Goal for this Chapter. We are going to learn answers to the following questions: Why there any instabilities in the atmosphere? How can we make the atmosphere more stable? Why cloud droplets seldom reach the ground?
Cloud Development & Precipitation
We are going to learn answers to the following questions:
Unstable Air. Warmth from the forest fire heats the air, causing insta. near the surface; warm, less dense air bubbles upward, expanding & cooling as it rises – rises air cools to dew point, condensation begins & cumulus cloud forms
Conditionally unstable air – when unsaturated stable air is lifted to a level where it becomes saturated and warmer than the air surrounding air
How clouds form: a) surface heating & convection; b) forced lifting along topographic barriers; c) convergence of surface air; d) forced lifting along weather fronts
Formation of lenticular clouds: Moist air rises in the upwind side of the wave, it cools and condenses, producing cloud; in the downwind side, air sinks and warms – the cloud evaporates
Water droplets and ice crystal are in equilibrium; water vapor molecules > liquid is saturation vapor pressure over water is greater than it is over ice