Climate and weather have intrigued people for 1000’s of years. Mankind has seen droughts, floods and ice bringing many species into extinction and mankind on the brink of extinction.
Before we can even start looking at any aspect of climate and weather its important to define these concepts. Climate refers to the long-term average weather of a geographical region taken over 30 years or more. Weather can be describes as the day-to-day atmospheric conditions of a particular place. Aspects of weather include hat and cold, humidity, wind, clouds, fog, hail, sleet and rain. The last three aspects are also known as precipitation. Climate is very unstable over time. Currently the earth is going through a warming period which is intensified by global warming. Climate has a huge impact on population growth and human activities.
Weather in life occurs in he lowest part of our atmosphere and it is here where people have the greatest impact. The earth’s atmosphere consists out of different layers with its own unique characteristics.
i) The troposphere
The troposphere reaches up to a height of approximately 16km above the earth’s surface at the equator and 9km over the poles. It contains more than 80% of all the gases in the atmosphere. The temperature decreases from an average of 22˚C to -50˚C. This temperature decrease takes place at a specific lapse rate known as the environmental lapse rate.
ii) Tropopause
The tropopause is not a layer but rather a transition zone between the troposphere and the stratosphere. The tropopause is characterized by a temperature increase with increase in altitude known as temperature inversion. This temperature increase is the result of a high concentration of ozone (O3) which absorbs harmful ultraviolet sun rays. Natural holes in the ozone exist over the poles but chlorofluorocarbons (cfc’s) released by humans into the atmosphere destroy ozone, allowing dangerous levels of radiation to pass.
iii) Stratosphere
The temperature increases from -60˚C to just below 0˚C. The increase in temperature is due to the presence of ozone.
iv) Stratopause
The stratopause forms the transition zone between the stratosphere and mesosphere.
v) Mesosphere
In the mesosphere the lack of gases results in very little absorption of solar heat energy.
vi) Mesopause
The mesosphere forms the transition zone between the mesosphere and the thermosphere.
vii) Thermosphere
The thermosphere has virtually no gases although the temperature increases sharply. In this layer you are completely expose to the full force of solar radiation.
