EESA09H3 Lecture Notes - Lecture 2: Ultraviolet, Ozone Depletion, Cumulonimbus Cloud
21 May 2018
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Wind
EESA09- Lecture 2- Science of Wind
Vertical structure of the Atmosphere:
- There are four main layers in the atmosphere.
○Thermosphere: The layer of atmosphere that is farthest to the ground.
Temperature within this layer increases as the altitude increases because of the
ability of nitrogen and oxygen to absorb solar radiation.
○Mesosphere: As altitude within this layer increases, the temperature decreases
due to vertical air motions.
○Stratosphere: Lots of ozone molecules are present and absorbs ultraviolet
radiation from the sun and heats it up- as altitude within this layer increases, the
warmer it will get. Ozone in this layer absorbs the ultraviolet radiation so that it
protects organisms from the dangerous effects of the sun ultraviolet radiation.
○Troposphere: the layer of atmosphere that is closest to ground level- the
majority of weather events occur in this layer (this layer is the main focus for the
class)
- As altitude increases, the temperature of the atmosphere decreases. The layers near the
earth’s surface is hotter than the layers closest to the sun because the layers at the top
of the atmosphere are transparent which means the sun’s rays penetrate through the
layers and do not absorb the heat
●Ozone hole: The ozone concentration of the lower stratosphere declines (refer to
lecture 1 notes)
Categorizing Clouds: Clouds are formed as rising air cools and sinking air warms: cooling air
leads to condensation or formation of clouds
Clouds are categorized by the liquid constituents of the atmosphere and the location in which it
can be found. (Definitions will be on the midterm; for example: write about the characteristic of
a cumulonimbus)
Wind
●Stratus, Stato
○Clouds that are formed in layers.
○Low-levelled clouds
●Cumulus, cumulo-
○‘Puffy’ shape
○Name will vary depending on its location
●Cirrus, Cirro-
○Always high level clouds
●Nimbus, nimbo-
○Rain clouds
■Cumulonimbus= thunder clouds
●Alto
○Any clouds that are found in the middle
What is Wind?
●Wind is the term used to describe the movement of air
●Wind can be felt but cannot be seen directly however its effects can be seen
Why does wind move?
1. When there is a difference in air pressure, a pressure gradient forms
2. Air will begin to move from areas of high pressure to low pressure- this movement is
called a pressure gradient force (PGF)
●Wind has a wavy nature to it- it does not simply travel in a straight line.
Atmospheric Pressure:
●Changes in atmospheric pressure can be horizontal or vertical.
○Vertical Pressure gradients are dominant in the lower half of the atmosphere while
horizontal pressure gradients are dominant in the upper atmosphere.
○Why doesn’t wind focus its movement on the ground due to gravity?
○Why doesn’t wind move upward due to the fact that pressure decreases with height?
Document Summary
There are four main layers in the atmosphere. Thermosphere : the layer of atmosphere that is farthest to the ground. Temperature within this layer increases as the altitude increases because of the ability of nitrogen and oxygen to absorb solar radiation. Mesosphere : as altitude within this layer increases, the temperature decreases due to vertical air motions. Stratosphere : lots of ozone molecules are present and absorbs ultraviolet radiation from the sun and heats it up- as altitude within this layer increases, the warmer it will get. Ozone in this layer absorbs the ultraviolet radiation so that it protects organisms from the dangerous effects of the sun ultraviolet radiation. Troposphere : the layer of atmosphere that is closest to ground level- the majority of weather events occur in this layer (this layer is the main focus for the class) As altitude increases, the temperature of the atmosphere decreases.
