III. Water and Climate

Like plants and animals, people need fresh water to live. Water is influential in shaping climates.

How long can a human being survive without water? 3 Days

A. Oceans and Climate Oceans and large bodies of water help spread Earth’s heat. Global temperature differences and wind patterns create ocean currents. These currents move across great distances, transporting warm water from the tropics to the poles. also transport cool water from the poles to the tropics.

water temperature affects the air temperature. Warm water warms up the air above it Cold water cools the air above it water takes longer to heat or cool than land

as air and land heat up, water remains cooler Wind blows over this cool water, which cools the land nearby. Land near water will be cooler during the heat of the summer.

However, water remains warmer than land during the winter Land near water will be warmer during the cold of the winter

What heats up faster: Water or Land?

B. The Water Cycle Earth’s water is always moving. This process is known as the water cycle. Water Cycle – the movement of water from Earth’s surface into the atmosphere and back.

Water heats up and moves from rivers, oceans and lakes up into the air. As water cools, it falls back to Earth and flows into rivers and streams, oceans, and lakes. The water cycles includes both precipitation and evaporation Evaporation – the process in which a liquid changes to a gas.

The Water Cycle The Sun’s heat makes water evaporate from a sea or lake and rise into the sky as water vapor Water vapor condenses to form clouds, made up of little drops of water. As clouds and moist air rise, they cool. Larger droplets of water condense and fall to the ground as rain. Water seeps into the ground or runs into streams – the water then flows into a lake or ocean or evaporates.

IV. Air Circulation and Precipitation

A. Moving Air Belts of rising and sinking air form a pattern around Earth. Air rises near the Equator, sinks at the edge of the tropics, rises in the temperate zones, and sinks over the poles. The area of rising air near the equator is known as the Intertropical Convergence Zone, or ITCZ There tends to be more precipitation in areas of rising air than areas of sinking air.

What causes wind? heat from the sun warms the air warm air is lighter than cold air causing it to rise. cool air is pushed up and away by rising warm air, forming winds high above the Earth. Eventually, this cool air begins to sink back to the ground

How do winds form? Cool air is pushed up by rising warm air

Cool air has little moisture and there is little rain fall in areas where cool air sinks. As sinking air reaches the surface, winds form that blow along the surface and pick up moisture. These winds blow from areas of sinking air, or high pressure, to areas of rising air, or low pressure.

B. Raging Storms Most storms occur when two air masses of different temperatures or moisture contents come together. Some storms bring small amounts of rain or snow. Others bring large amounts of heavy wind and rain causing great destruction.

Tropical Cyclone – is an intense rainstorm with strong winds that forms over oceans in the tropics. Hurricane – is a dangerous type of cyclone that forms over the Atlantic Ocean The east coast of North America sees a large number of Hurricanes due to its location along the Atlantic Ocean Tornado – a swirling funnel of wind that can reach 200 miles per hour. Often more dangerous than Hurricanes, but they cover a smaller area.

Many other storms are less dangerous Blizzards often strike North America during the winter months. Severe Thunderstorms are common in the spring and summer.