Layhers of the Atmosphere

Introduction

In Meteorology Today, Chapter 1 the author discusses

the composition and the structure of the atmosphere and

how these characteristics affect our weather. We begin

by looking at how pressure (and thus density) varies as

we increase in altitude. Since the surface pressure as

measured anywhere on the surface of the earth depends

upon the amount of air molecules in a column and the

fact that gravity causes these air molecules to

accumulate closer to the surface of the earth, we see the

pressure change very rapidly with altitude. We will

address pressure measurements in more detail later in

the course. For now, suffice it to say that at higher

altitudes (such as on mountain plateaus) the pressure as

measured by a barometer will read lower than what it

would at sea level due to the fact that less air molecules

are in a column above the mountainous plateau.

Layers of the Atmosphere Identified by Temperature

The layers of the atmosphere are identified by observing the change in temperature with altitude from the surface of the earth to the

very top of the atmosphere. The four main layers (together with their transition layers) are the troposphere, where temperature

decreases with altitude and the tropospause where the temperature either remains constant or increases slightly. The tropospause

serve as a “lid” that caps the weather that occurs in the troposphere. Later in the course you will see how the tropospause affects the

vertical development of severe storms.

The next layer of the atmosphere is the stratosphere, where we see

the temperature increase with altitude. This layer of the atmosphere

is extremely stable and any pollutants that make their way into the

stratosphere will remain there for hundreds of years. An example

would be very fine particulate matter ejected into the stratosphere by

volcanoes or exhaust emissions from aircraft that can fly within the

stratosphere. We also find a large concentration of ozone in...