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Climate and Weather
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

DEFINITIONS:
a)
WEATHER – short term, daily
characteristics of the atmosphere (i.e.
wind, humidity, cloud cover, visibility,
temp., precip., and air pressure).
b)
CLIMATE – long term characteristics of
our atmosphere, yearly averages of daily
weather patterns.

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
CLIMATE CLASSIFICATION:
a)
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
CLIMATE CLASSIFICATION:
b)


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
Climograph
Hythergraph
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

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?
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

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
INTRODUCTION
Most weather systems in the midlatitudes 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

Midlatitude Cyclone Formation a)
Midlatitude Cyclone Formation b)
Midlatitude Cyclone Formation c)
Midlatitude Cyclone Formation d)
Midlatitude Cyclone Formation e)
JET STREAM
Bands of upper air movement at
altitudes between 9000m and 12000m
 Flow at speeds up to 450 km/h

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