End of Year – Science Study Guide Earth Systems and Structures

Earth Systems Weather – daily temperature and precipitation Climate – average temperature and precipitation over time

Weather Tools Thermometer – used to tell the temperature Barometer – used to tell the amount of air pressure Rain Gauge – collects the amount of rainfall that has fallen Hygrometer – tells how much moisture is in the air (humidity) Anemometer – indicates wind speed Wind Vane – indicates wind direction

Types of Clouds Cirrus Wispy clouds that are the highest clouds in the atmosphere; made of ice crystals Change in weather is coming Stratus These clouds form in layers, blanket the sky, and bring gray/dull weather (fog) but they don’t bring rain

Types of Clouds Cumulus Large white puffy clouds that may bring light rain Cumulonimbus Large dark clouds that bring severe storms. Can expect heavy rains.

Air Pressure Low Pressure (lousy) Air rises and forms water droplets Strong winds and dropping temperatures Usually results in rain and storms High Pressure (happy) Several days of clear, sunny skies Causes air to sink Mild winds and stable temperatures

Air Masses and Fronts Air Mass – a large body of air with about the same temperature and humidity throughout Polar Air Mass – Cold air Tropical Air Mass – Warm air Front – the boundary where two different air masses meet

Front Symbols

Types of Fronts Warm Front Laid back – rises over the cold front Rain showers Warmer air follows the front Cold Front Rude – takes over and pushes warm front up Stormy/Windy weather Cooler air follows the front

Types of Fronts Stationary Front Cold and warm front meet and neither moves Overcast and rainy weather Occluded Front Two cold air masses meet and the warm air between them is pushed upward. Rain and Snow Cool Temperatures

Types of Storms Type of StormWhere it FormsTime of Year ThunderstormWithin large cumulonimbus clouds Spring or Summer TornadoCumulonimbus CloudsSpring or Summer HurricaneOver warm ocean waterLate Summer and early Autumn/Fall

Weather Patterns Local Weather Patterns: Moderate temperature and moderate rainfall with hot Summers and cold Winters Thunderstorms, Tornadoes, and Hurricanes possible between Spring and Fall

What Affects Weather Patterns? Equator – an imaginary line that divides the Earth into the Northern and Southern Hemispheres Latitude – distance north or south of the equator

Climate Zones Tropical Zones Located closest to equator so it gets most energy from the sun; warm and hot all year Polar Zones Located farthest from the equator near North and South Poles; get least amount of energy from sun; cool and cold all year Temperate Zones Between Polar and Tropical Zones; amount of energy from the sun changes throughout the year; seasons with very different temperatures

Two Hemispheres Northern HemisphereSouthern Hemisphere Located above the equatorLocated below the equator Opposite weather of Southern Hemisphere Opposite weather of Northern Hemisphere In Temperate Zone: Summer is June, July, AugustSummer is Dec., Jan., Feb. Winter is Dec., Jan., Feb.Winter is June, July, August Fall hereSpring there Spring hereFall there

Also Affecting Weather Patterns Mountains higher places have cooler temperatures than low places Warm air moving toward mountains will rise and cool (causing rainfall) Bodies of Water tend to have milder weather In Winter – warmer ocean water keeps nearby land warm In Summer – cooler ocean water keeps nearby land cool

Currents Current – a flow of air or water in a certain direction Two Types: Global wind currents – in the air (includes Jet Streams) Ocean Currents – in the water (includes Gulf Stream, El Nino, La Nina)

Global Winds Polar Easterlies – Travel from the Poles (east to west) Westerlies - Between the Poles and Tropics (travel west to east); where we live Trade Winds- Travel toward the Equator (east to west) The paths of global winds curve because…Earth spins on its axis.

Jet Stream An air current in the upper atmosphere that flows from East to West. Dip, bend and change position to affect North America’s weather Affect the paths of storms. From the North (dips South) – Polar Jet Stream lets cold air from Canada flow down into the US From the South (bends North) – Subtropical Jet Stream lets warm air flow in from the South

Ocean Currents Warm Currents (Tropical) – ocean currents that flow away from the equator; carry warm water near coastlines to cooler areas Cold Currents (Polar) – ocean currents that flow away from the poles; bring cooler temperatures to hotter coastlines

Ocean Currents The Gulf Stream – a warm ocean current in the Atlantic Ocean that moves warm waters toward the north. Helps keep weather mild during cooler months by warming the air and land. El Nino – unusual warming of surface temperatures in the Pacific Ocean, drought in Western US, Flooding in S. America La Nina – unusual cooling of the surface temperatures in the Pacific Ocean, flooding in Western US, drought in S. America