When a cold air mass catches up with a warm air mass, the cold air slides under the warm air and pushes it upward. As it rises, the warm air cools rapidly. This configuration called a cold front, gives rise to cumulonimbus clouds, often associated with heavy precipitation and storms.

Weather and deserts

Many people rely on weather reports to prepare for daily weather conditions. If the report indicates that the temperature is going to be cold, we make sure to dress in layers and wear hats and coats. If the weather report predicts rain, we know that it is wise to bring our umbrellas. Without weather reports, we would have a much harder time figuring out how to prepare adequately for the weather.

Imagine having to check the weather forecast to know if your food will have what it needs to grow. That is the challenge for many farmers in Southern California. Do farmers in the Central Valley of California have the same challenge? The likelihood of it raining will depend on many factors. In this concept, you will consider how properties of the atmosphere, and their interactions with land and water influence the weather.

​the properties of the atmosphere at a given time and location, including temperature, air movement and precipitation

Weather

liquid water that fall from the sky

Rain

the layers of gases that surround a planet

Atmosphere

​Vocabulary

• ​Exosphere-upper most sphere near vacuum of space

• Thermosphere-Temperatures climb sharply then level off Solar activity strongly influences the temperature

• Mesosphere-Temperature decreases with altitude. The coldest temperatures about -90° C, are near the top of this layer.

• Stratosphere-has dry air, containing little water vapor meaning few clouds, contains the ozone

• Troposphere- lowest layer, contains about 75-85% of the atmospheric mass, the wettest layer, and contains most weather

Vocabulary

The boundary between the mesosphere and the thermosphere is called the mesopause.