Weather & Climate
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Weather & Climate Defined
• Weather- “the state of the atmosphere with
respect to heat or cold, wetness or dryness,
calm or storm, clearness or cloudiness”.
• Climate – “the average course or condition of
the weather at a place usually over a period of
years as exhibited by temperature, wind
velocity, and precipitation”
Weather is…
• The state of the atmosphere, to the degree
that it is hot or cold, wet or dry, calm or
stormy, clear or cloudy.
• Most weather phenomena occur in the
troposphere.
• Weather generally refers to day-to-day
and/or hour to hour/or minute to minute
atmospheric conditions on a local scale.
Weather can not occur without
an…
Atmosphere
Climate
• encompasses the average
temperature, humidity, atmospheric
pressure, wind, precipitation,
atmospheric particle count and
other meteorological elemental
measurements in a given region
over long periods.
Global Warming
• To a scientist, global warming
describes the average global surface
temperature increase from human
emissions of greenhouse gases.
• Its first use was in a 1975
• Not used by the scientific community.
Climate Change
(inadvertent climate modification old school termonology)
• is the significant and lasting changes in
the (re)distribution of climate patterns
over periods ranging from decades to
millions of years.
• climate change is a change in the statistical
properties of the climate system when
considered over long periods of time;
natural or human impacted
High Pressure
• Higher pressure than what is
normal for that altitude.
• What do you notice about the air in this
region?
• Brings clear skies and fair weather.
– The sinking cold air warms as it does so and
becomes stable.
Low Pressure
• A low pressure region (depression
or cyclone) is caused by rising air.
• Clouds, rain, and very strong winds
occur.
• Why do you think that is?
Clouds
• See Cloud ppt.
Temperature & Humidity
• Temperature - Air higher in pressure is usually
cooler air and air lower in pressure is usually
warmer air.
• What happens when the two meet?
• Humidity - How much water is in the air over
how much water could fit in the air (right before
the water begins to condense out of the air).
• Dew point - Temperature at which the moisture
saturates the air is the dew point.
Wind
• Caused by the earth’s surface
being heated unevenly by the sun.
• Why would the earth’s surface heat unevenly?
• How do you think this causes the wind?
Thunderstorms
• What type of cloud causes these?
• Consists of gusty winds, heavy rain and hail.
• Can result in a tornado
Lightning
• What did you observe in all the lightning
demonstrations? How does this suggest
lightning occurs?
• Interesting Fact: More people are killed by
lightning per year than
in tornadoes!!!
Atmosphere
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Troposphere - Most of the weather
occurs.
Stratosphere - 19% of the atmosphere’s
gases are here; ozone layer is here
Mesosphere - Most meteorites burn up
here.
Thermosphere - High energy rays from
the sun are absorbed; hottest layer.
Exosphere - Molecules from atmosphere
escape into space; satellites orbit here.
Greenhouse Gases
• Greenhouse gases - carbon dioxide, methane,
water vapor, nitrous oxide, and
fluorocarbons.
• Are they all bad? We will find out through
learning activity (lab).
• Retain the heat through a process called the
Greenhouse effect.
Greenhouse Effect