Alternative transcript:

ground Condensation cools-water droplets form Surface Runoff flows from land into ocean Evaporation from liquid to vapor EARTH'S CHANGING CLIMATE FACTORS AFFECTING WEATHER AND CLIMATE Atmosphere • The atmosphere is a mixture of gases that surrounds the Earth • Has five different layers; each has different properties • Air Temperature and Pressure change with altitude • Weather occurs in the layer closest to Earth (troposphere) Exosphere ● 400 km altitude Thermosphere Mesosphere Stratosphere Troposphere 300 km 50 km 40 km 10 km Layers of the Atmosphere • Exosphere - the outermost layer of the Earth's atmosphere, where atmospheric pressure and temperature are low. • Ionosphere - the atmospheric layer between the mesosphere and the exosphere; it is part of the thermosphere. • Mesosphere - the atmospheric layer between the stratosphere and the ionosphere. • Stratosphere - the atmospheric layer between the troposphere and the mesosphere. The stratosphere is characterized by a slight temperature increase with altitude and by the absence of clouds. • Thermosphere - the layer of the atmosphere located above part of the ionosphere (starting at the coldest part of the atmosphere) and below outer space; it consists of the exosphere and part of the ionosphere. Troposphere - the lowest layer of the Earth's atmosphere. The weather and clouds occur in the troposphere. ● EARTH'S CHANGING FACTORS AFFECTING WEATHER AND CLIMATE Air Masses body of air with a certain temperature and moisture level • Can be warm or cold • Can contain a lot of moisture or not a lot of moisture Fronts CLIM A ΤΕ places where air masses meet • 4 Types: Warm, Cold, Occluded, Stationary • Each kind can bring different kinds of weather Air Pressure Winds • How much the earth's atmosphere is pressing down on us • Measured with a BAROMETER If it CHANGES, then new weather is on the way: Falling Air Pressure = stormy weather coming Rising Air Pressure = fair weather coming Steady Air Pressure = no change is coming created from differences in air pressure • Moves from areas of HIGH to LOW pressure • Greater the difference in pressure, the FASTER the wind blows • Measured with wind vanes and anemometers or you can estimate with the Beaufort Wind Scale Global Winds • Thousands of kilometers long; can cause weather to move in different directions • et stream, prevailing westerlies, doldrums, horse latitudes, trade winds • Caused by the temperature difference in different regions Hot Tropical Regions-causes air to rise • Cold polar Regions-causes air to sink EARTH'S CHANGING CLIM A ΤΕ FACTORS AFFECTING WEATHER AND CLIMATE Ocean Relative Humidity Measure of the amount of moisture in the air compared to what the air could hold How "full" of water the air is Expressed as % • 100% relative humidity = saturated air Controlled by temperature 1. Warm air holds more moisture than cool air (more space for water vapor between air molecules) 2. As air warms, relative humidity decreases 3. As air cools, relative humidity increases Dew Point =Temperature at which the air is saturated (100% relative humidity) Ocean currents affect the temperature of the land they pass by • Cold ocean currents = cooling effect • Warm ocean currents = warming effect • Temperature changes affect pressure - which then creates WINDS • winds blow this cooling or warming effect over the land