Exploring Earth's Lower Atmosphere
Exploring Earth's Lower Atmosphere
Onderdelen in deze les
Exploring Earth's Lower Atmosphere
What do you already know about the troposphere and stratosphere?
Learning Objective
At the end of the lesson you will be able to describe the main features of the troposphere and stratosphere, and explain their importance to life on Earth.
Layers of the Atmosphere
The atmosphere is divided into 5 layers based on temperature and other characteristics. Today we focus on the troposphere and stratosphere.
What is the Troposphere?
The troposphere is the bottom layer of Earth’s atmosphere and where all weather happens. Most types of clouds are found in the troposphere, and almost all weather occurs within this layer. The troposphere is by far the wettest layer of the atmosphere
Features of the Troposphere
It is about 8 to 15 km thick, contains much of the air we breathe, and gets colder with height. The height of the top of the troposphere varies with latitude, it is lowest over the poles and highest at the equator. It can be as high as 20 km near the equator, and as low as 7 km over the poles in winter.
Life in the Troposphere
All life, aeroplanes, and weather systems are found in this layer. Air is warmest at the bottom of the troposphere near ground level. Air gets colder as one rises through the troposphere. That's why the peaks of tall mountains can be snow-covered even in the summertime.
What is the Stratosphere?
The stratosphere is the second layer, above the troposphere. It stretches to about 10km to 50 km above Earth. The lower boundary of the stratosphere is called the tropopause; the upper boundary is called the stratopause.
The Ozone Layer and Temperature rise
The ozone layer, found in the stratosphere, protects Earth from harmful ultraviolet rays.
Ozone, a type of oxygen molecule that is relatively abundant in the stratosphere, heats this layer as it absorbs energy from incoming ultraviolet radiation from the Sun. Temperatures rise as one moves upward through the stratosphere. This is exactly the opposite of the behavior in the troposphere. Commercial jet aircraft fly in the lower stratosphere to avoid turbulence as the stratosphere is very dry air, containing little water vapor. Because of this, few clouds are found in this layer.
Troposphere vs. Stratosphere
1.Temperature rises with height Calm, little weather.
No Cloud cover
Dry
Occurs in the Zone of non-convection current.
Stratosphere
Troposphere
1. Temperature drops with height Contains most air.
Abundant Clouds
Abundant Moisture
4. Occurs in the Zone of convection cover
Why are These Layers Important?
The troposphere supports life and weather. It helps regulate Earth’s temperature and climate.
It supports the water cycle.
The stratosphere protects us from UV radiation. It provides a stable layer of air, so there is very little weather disturbance.
Review: Key Points
Remember: The troposphere is closest to us and full of activity. The stratosphere holds the ozone layer and acts as Earth’s sun shield.
Write down 3 things you learned in this lesson.
Write down 2 things you want to know more about.
Ask 1 question about something you haven't quite understood yet.
