Earth’s Weather and Climate

Our Weather and Climate The condition of the atmosphere at a certain time and place. Changes daily Climate The overall weather patterns of an area Changes occur over long periods of geologic time

Solar Energy Earth receives energy from the sun by radiation. Radiation is the transfer of energy as electromagnetic waves. The suns radiation enters Earth as Visible light Infrared waves - heat Ultraviolet radiation

Solar Energy from the Sun Energy from the sun is transferred around Earth by radiation and convection.

Energy from the sun creates convection currents in the atmosphere and oceans

Convection Currents Convection is the transfer of thermal energy by the circulation of liquids and gases. Warm air or water rises It’s less dense Cool air or water sinks It’s more dense

Ocean Currents Warm water rises and cooler water sinks

Wind and Ocean Currents Influence Earth’s Weather and Climate

Temperature of Our Oceans Ocean water cools down and warms up much slower than land or air. Oceans keep temperatures for nearby land much more moderate. Temperatures are less extreme Doesn’t get too cold or too hot This keeps coastal areas cooler in the summer and warmer in the winter.

Land and Sea Breezes Winds caused by uneven heating of air above ocean water and land. Land heats up and cools down much faster than ocean water. Land gets much hotter during the day and much cooler at night.

Coastal Areas experience Sea Breezes during the day

Coastal Areas also Experience Land Breezes at Night

Sea Breezes by Day Land Breezes by Night

Valley and Mountain Breezes

Ocean Currents Stream like movements of water in oceans Heat is transferred around the world by ocean currents through convection. Over ½ the heat that reaches the Earth from the sun is absorbed by the oceans surface.

Surface Currents Currents at or near the surface of the ocean Caused by WINDS! Affect weather and climate for coastal regions around the world. Warm currents originate at the Equator Cold currents originate at the Poles

Deep Water Currents Deep currents far below the surface of the ocean. Water is cold and salty which makes it more dense and sinks to the ocean floor.

Currents Trade Places Water from deep currents get warmer as they reach the equator and starts to rise. Water from surface currents get colder as they reach the poles and starts to sink Heat is transferred by convection currents, in our oceans. Warm water rises and cold water sinks

Ocean Water Currents

Changes in Ocean Currents El Nino – the warming of water in the Pacific Ocean La Nina – the cooling of water in the Pacific Ocean

Causes Changes in Weather El Nino Weather Rain and flooding along the Pacific Coast Tornadoes and thunderstorms in South US Fewer than normal hurricanes in the Atlantic La Nina Weather Snow and rain on the west coast Cold weather in Alaska Warm weather in the rest of the USA Drought in the south west More hurricanes in the Atlantic

Warm air rises and cool air sinks Wind currents Warm air rises and cool air sinks

Wind Currents Created by differences in Air pressure Caused by unequal heating of the Earth from the sun Equator – Warm, less dense air Low air pressure Poles – Cold, more dense air High air pressure

Atmospheric/Air Pressure The force of the air pushing on any surface. Measured in Millibars Decreases with altitude Changes with air temperatures Creates wind!

Barometer – Measures Air Pressure

Air Pressure Weather Map Isobars – Lines on a weather map that show equal Atmospheric Pressure H = High Pressure L = Low Pressure

Convection Cells of Air Create Winds

Jet Streams High-speed winds that can reach up to 500 km/hour high up in the sky.

Wind Speed Measured by an anemometer Digital

Weather Map showing Isobars and Windspeed/Direction

Air Masses – large bodies of air that have similar temperature and moisture throughout

Types of Air Masses Continental - form over land; dry Maritime - form over water; wet and Tropical - form in a tropical region; warm Polar – form in a polar region; cold

Air Masses mP – Maritime Polar Cold and Wet cP – Continental Polar Cold and dry mT – Maritime Tropical Warm and Wet cT – Continental Tropical Warm and Dry

Air Masses

Fronts Boundary that forms between two different air masses 4 types of fronts: Cold, Warm, Occluded, Stationary

Cold Front When a cold air mass replaces a warm air mass Produces colder temperatures and more precipitation

Warm Front When a warm air mass replaces a cold air mass. Creates warmer temperatures and some precipitation.

Weather Map

The amount of moisture or water vapor in the air. Humidity The amount of moisture or water vapor in the air.

Relative Humidity Relative Humidity – the amount of moisture the air contains compared with the maximum amount it can hold at a particular temperature.

Measuring Humidity Psychrometer Hygrometer Measures Relative Humidity Measures Humidity Psychrometer

Severe Weather Weather that can cause property damage and even death. Thunderstorms Tornadoes Hurricanes

Thunderstorms Intense weather systems that produce strong winds, heavy rain, lightning and thunder Occur when warm, moist air rises rapidly in an unstable atmosphere. Can cause high winds, hail, flash floods, and tornadoes.

Tornadoes A rotating column of air that has high wind speeds and low central pressure that touches the ground. Starts as a funnel cloud formed from a cumulonimbus cloud Produced by thunderstorms 75% occur in the US

Wall Cloud

Wall Cloud – Take Cover

Hurricanes Most powerful storms on Earth Form in warm ocean waters by the equator Fueled by warm water and moist air Die out over cold water and land

Hurricanes, Typhoons, Cyclones Form in warm ocean waters by the equator