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

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

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 29.92 “ 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

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

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

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

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

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

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