1. Climate and Weather

2. Major Factors
Solar radiation is the major factor in determining the climates of our world
Other factors (LOWNER)
Latitude
Ocean Currents
Winds and Air Masses
Near Water
Elevation (Altitude)
Relief

3. DEFINITIONS:
WEATHER – short term, daily characteristics of the atmosphere (i.e. wind, humidity, cloud cover, visibility, temp., precip., and air pressure).
CLIMATE – long term characteristics of our atmosphere, yearly averages of daily weather patterns.

4. in some areas “weather” and “climate” are almost the same thing.
if the weather is very consistent and does not change much from day to day (i.e. Africa)
in other areas the weather may differ greatly from one day to another so “weather” and “climate” are much different
in most locations in the world the weather will change daily, but the over all climate remains constant during a given time of year

5. CLIMATE CLASSIFICATION:
purpose for a classification system: to identify patterns that exist on the earth’s surface
this allows us to study the factors controlling our climate
many classification systems are based on 2 variables:
temp and precip

6. WEATHER MISINTERPRETATION
We often misquote the weather person!
What does 70% probability of precipitation (POP) mean?
What is partly sunny?
Some words really don’t mean what they seem to
Cloud cover is really sky cover
Zero visibility includes visibility up to a distance of below 100m
“cloudy with sunny periods” or “sunny with cloudy periods” – what is the difference?

7. CLIMATE CLASSIFICATION:
Collection of climate data: 2 ways
Climograph – a combination graph that displays average monthly temperatures as a line graph and monthly precip as a bar graph
Hythergraph – a scatter graph in which each of the 12 points represents both the average monthly temp and the total monthly precip for a place

8. Climograph

9. Hythergraph

10. WEATHER MISINTERPRETATION
We often blame the meteorologist for predicting the wrong weather, when often it is our fault
Often words are too vague and give rise to misinterpretation
A forecast needs to be clear, specific, and concise, not too much information at once

11. Air Masses
Some areas have “predictable” weather because one air mass dominates the area for a very long period of time
In much of the mid-latitude areas of the world, weather is influenced by constant movement of air masses of different characteristics and the meeting of these air masses

12. INTRODUCTION Most dramatic and influential zone is the polar front
Along the polar front cold, dry polar air meets warm, humid subtropical air
Front = the boundary zone between two different air masses

13. INTRODUCTION
Most weather systems in the mid-latitudes develop due to the interaction of the two different air masses
Like the front lines between two opposing armies meeting
Warm air (less dense) is forced to rise over the colder (more dense) air mass

15. Midlatitude Cyclone Formation a)

16. Midlatitude Cyclone Formation b)

17. Midlatitude Cyclone Formation c)

18. Midlatitude Cyclone Formation d)

19. Midlatitude Cyclone Formation e)

20. JET STREAM
Bands of upper air movement at altitudes between 9000m and 12000m
Flow at speeds up to 450 km/h

22. JET STREAM If your location is:
North of jet stream you will be affected by cold, dry air
South of jet stream you will be affected by warm, moist air
Directly under jet stream you will experience storms and unsettled weather