January 9, 1998

Climate vs. Weather
The Professional Meteorologist
The Ozone Layer

Climate vs. Weather

Climate and weather are different aspects of meteorology. Weather refers to events that occur in specific time periods, whereas climate refers to averages or trends in weather over long periods of time.

If I were to say that Òyesterday in Tallahassee, there was a thunderstormÓ, I am talking about a weather event.

If I were to say that Òduring the Summer, there are usually afternoon thunderstorms in TallahasseeÓ, I am talking about a particular aspect of TallahasseeÕs climate.

Knowing the climate in a particular part of the world helps you guess what the weather will be at a given time as climate is basically concerned with what the weather is like, on average, in a geographical region of the world.

Different climates-Climate Classification

There are many adjectives to describe the climate of a region such as desert, rain forest, tundra, savannah, continental, maritime, and many others. Climates are classified based on a geographic regionÕs annual precipitation, average temperature, and humidity.

The Ancient Greeks were the first to implement climate classification regimes. They broke the Earth into torrid zones, polar zones, and temperate zones.

In 1918, a German scientist, Waldimir Koppen, subdivided climatic zones into 5 major regions:

Climate Characteristic
Tropical Moist Climates All months have an average temperature above 64 F. There is no real winter season.
Dry Climates Deficient precipitation most of the year.
Moist mid-latitude climates Warm-to-hot summers with mild winters.
Moist mid-latitude climates Warm-to-hot summers and cold winters.
Polar climates Extremely cold winters and cool summers.

There are many other classifications employed by meteorologists and climatologists such as: deserts, rain forests, savannahs, maritime, continental, semi-arid, and mediterranan to name a few.

What determines the climate of a region?

Climate is determined by a number of geographical factors including:

Later in the semester, once we have covered more about the fundamentals of the atmosphere, we will revisit climate once again in more detail.

Climatic problems

Many scientists and environmentalists are concerned that there are dangerous changes occurring to our climate that are the result of anthropogenic (man-made) causes.

The Greenhouse Effect and the Ozone Hole are two climatic issues that have caught the attention of many worldwide since the early 1980s.

The Greenhouse Effect is referring to the introduction into the atmosphere of gases (such as Carbon diOxide, Methane, and others) which have the ability to ÒtrapÓ heat within the atmosphere like a blanket. Shortwave radiation is allowed into the atmosphere, but longwave radiation is trapped in and as a result, the average global temperature is theorized to be on the rise.

The Ozone Hole is another example of manÕs impacts on the EarthÕs climate. High up in the stratosphere, some 25-50 km above the surface, there is a high concentration of the substance Ozone (O3). Ozone is actually 3 oxygen atoms bonded together.

Ozone has the ability to absorb ultraviolet radiation from the sun that would otherwise penetrate the entire atmosphere and would be very dangerous to surface dwelling creatures, humans included.

There are a broad classification of chemicals called Chloro-Flouro-Carbons (CFCs) produced in mass quantities by the chemical and manufacturing industry. CFCs are found in a number of places in not just factories, but at home as well. Styrofoam and refrigerators are just 2 examples of substances or objects that contain CFCs.

CFCs are organic molecules. An organic chemical is a large group of substances that contain carbon.

When substances contain CFCs are disposed of, the CFCs do not readily decompose. They eventually find their way into the open atmosphere where they have the ability to interact and destroy stratospheric ozone.

The mechanism by which CFCs destroy stratospheric ozone is covered in the January 9 in-class lecture. It is interesting to note that while ozone is an essential substance in the stratosphere, in large quantities at the surface, it is poisonous to humans. In certain meteorological conditions, by-products of combustion from the burning of fossil fuels in automobile engines can produce ozone. In extreme cases, ozone advisories are issued when many who suffer from respiratory conditions are adversely affected.

In the early 1980s, scientists discovered the existence of an ÒOzone HoleÓ over Antarctica. It is still not clearly known why ozone is being destroyed at a higher rate over the South Pole. The existence of this ozone hole however has prompted a dramatic lifestyle change in the southern parts of Australia. Schoolchildren are requred to wear hats to and from school and there is an incidence of melanoma skin cancer 13 times higher than the rest of the World.

The Ozone Hole is only one example of a climatic change that meteorologists and other scientists need to address as we head into the 21st Century.

The professional meteorologist

It is hard to say exactly what the most important duty of the professional meteorologist is. Certainly one of their top priorities is to alert the public of dangerous or life-threatening weather. But meteorologists are also involved in a number of other important issues including the Ozone Depletion problem and the Greenhouse Effect.

Different branches of meteorology

Meteorology can be subdivided into a few different categories: