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Weather. Weather is …. The condition of the variables in the atmosphere at a given time and place. Variables – temp, air pressure, wind, cloud cover, precipitation, etc. Measuring Temperature. 3 different scales to measure temp. Celsius Fahrenheit Kelvin. ESRT pg 295 (13). Temp is ….
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Weather is …. • The condition of the variables in the atmosphere at a given time and place. • Variables – temp, air pressure, wind, cloud cover, precipitation, etc.
Measuring Temperature • 3 different scales to measure temp. • Celsius • Fahrenheit • Kelvin ESRT pg 295 (13)
Temp is …. • Measured using a thermometer (liquid filled glass tube) • Modeled on maps or charts by using isolines (isotherms)
The atmosphere is heated in many ways: • Insolation from the Sun • Conduction • Condensation • Coriolis effect
Heat energy is transferred in our atmosphere by the process of convection.
Transfer of heat energy through substances which can flow. A closer look at CONVECTION: water A convection cycle air Molten rock 5. Rising heated water moves outward to replace sinking cooler water. 4. Cooler more dense water sinks. 2. Lower density warmer water rises upward. 1. Heating causes a decrease in density Heat source 3. Water moves in to replace rising warm water
Air Pressure • Air Pressure- Pressure due to weight of the overlying atmosphere pushing down on a given area. • Pressure&Densityaredirectly related • Density = Pressure
Measuring Air Pressure Barometers • Mercury barometer • Standard reference but difficult to transport (inches of mercury) • Aneroid barometer • Non-liquid barometer that is smaller (millibars)
ESRT pg 295 (13) 1013.2 mb = ________ inches 1022.0 mb = ________ inches 30.53 inches = ________ mb 29.81 inches = ________ mb 29.92 30.18 1034.0 1009.5
decreases • As the temp of air increases the density & pressure _____________ • As the altitude increases the density & pressure _______________ decreases
The greater the amount of water vapor, the lower the air pressure & density…. but WHY? Water has less mass than other elements, which it replaces in the atmosphere.
Practice Questions According to the Earth Science Reference Tables, an air pressure of 30.15 inches of mercury is equal to 1. 1017 mb 2. 1019 mb 3. 1021 mb 4. 1023 mb
A balloon carrying weather instruments is released at the Earth’s surface & rises through the troposphere. As the balloon rises, what will the instruments generally indicate? 1. An increase in both air temp. & air pressure 2. A decrease in air temp. & an increase in air pressure 3. An increase in air temp. & a decrease in air pressure 4. A decrease in both air temp and air pressure
A temperature of 80°F would be approximately equal to how many degrees on the Celsius scale? 1. 27 3. 178 2. 299 4. 34
Where was he? • Jumped from 128,000 feet, or 24 miles!
Why Use Weather Maps? • Weather maps help us picture what is going on in the atmosphere. • Data is collected in multiple locations, and is displayed in a format that can be understood easily by people. • The information is placed on weather maps.
Isolines • Connect points of equal value on a map. Ex.: Temperature, Pressure, Elevation.
Types of Isolines • Isotherms – connect points of equal temperature. • Isobars – connect points of equal air pressure.