Moisture, Clouds, & Precipitation

Chapter 18

18.1 Water in the Atmosphere

Water vapor

● the most important gas to understanding atmospheric processes

● the source for all clouds and precipitation.

Water Changes of State

Latent heat: heat (energy) required to change state without a change of temperature

Humidity: amount of water vapor in the air

Water evaporates → air pressure increases

Saturated: 100% humidity, precipitation results

Higher temps= more water vapor

Relative Humidity: a ratio to show how much water is in the air compared to how much it can hold at a given temperature. (shown in %)

Low temps= less water vapor

Dew Point: the temperature at which relative humidity is equal to 100%

Video

Moisture condenses to form dew or fog

Calculating RH & Dew Point