1. Unit 3: Weather, Climate and Water
ESR 8E-SCI 8 Name:
Valenti/Rubeo Period:
Unit 3: Weather, Climate and Water

2. Weather (Wx)- condition of the lower troposphere for a given period of time (short period of time)
Climate- general or average weather patterns for an area over an extended period of time (from year to year)
Depends on
Nearness to a large body of water (ocean)
Elevation
Latitude
Topography
Meteorology - the study of weather and weather related variables

3. The variables:
Air Temperature
depends on intensity and length of day (sunlight or energy received)
measured with a thermometer
Atmospheric/Barometric Pressure - the force exerted by the column of air overhead
measured with a barometer
Average air pressure on Earth is “ or 1013 mb
Atmospheric Moisture/Humidity
Amount of water/water vapor in the air
measured with a sling psychrometer
Wind Speed and Direction- Wind is the circulation of air in the atmosphere
Circulation is a result of convection in the atmosphere
wind speed measured with an anemometer
wind direction measured with a wind vane
Atmospheric Transparency - a measure of how clean and clear the air is. It depends on:
number of pollutants (natural and man-made)
cloud cover
Precipitation cleans and clears the air

4. Facts about weather related variables:
all these variables interact in the troposphere - the lowest portion of the atmosphere
the relationship between these variables is very complex and poorly understood
the relationships are expressed as a probability of occurrence - very few occur with 100% certainty
accurate weather predictions are difficult to make - especially those made more than 36 hours in advance
changes in the weather are caused by the uneven distribution of energy within the atmosphere - it varies indirectly with latitude

5. Reading a Station Model
Wx variables are mapped on a Synoptic Wx Map
Station Models represent the variables for a 3 hour period of time for a certain city or airport location
Example of a station model
Information must be decoded in order to read a station model

6. Information must be decoded in order to read a station model
Air Pressure is the most difficult
Here’s how you do it:

7. H L Wind Speed and Direction
Wind - the movement of air parallel to the Earth’s surface - the horizontal movement of air
Facts about wind:
winds are caused by differences in air pressure between two locations
Wind always blows from areas of HIGH pressure to areas of LOW pressure
winds are caused by the unequal heating of Earth’s atmosphere - this results in differences in air pressure
It’s convection! H L

8. H L Air Masses Large body of air in troposphere with similar
Temperature
Humidity
pressure
Two Types of Air Masses:
Fronts- the boundary where two air masses meet (see ESRT for symbols) H L

9. Water exists in all three phases on Earth
Water Cycle
Water is constantly being transferred and transformed through the hydrosphere, atmosphere and even lithosphere
Water exists in all three phases on Earth
Solid (ice), liquid (water), gas (water vapor)
As water changes phase in the atmosphere it fuels our weather