Atmosphere Why is it rainy, cold, and dark this time of year?

Why is it rainy? To know why it rains so much in the PNW you need to know about the atmosphere. Composition of Air

Layers of Atmosphere

Troposphere Stratosphere Mesosphere Thermosphere layers of atmosphere felix baumgartner Red Bull Stratos

Layers of the Atmosphere The atmosphere is divided into five layers. It is thickest near the surface and thins out with height until it eventually merges with space.atmosphere 1) The troposphere is the first layer above the surface and contains half of the Earth's atmosphere. Weather occurs in this layer. 2) Many jet aircrafts fly in the stratosphere because it is very stable. Also, the ozone layer absorbs harmful rays from the Sun. 3) Meteors or rock fragments burn up in the mesosphere. 4) The thermosphere is a layer with auroras. It is also where the space shuttle orbits. 5) The atmosphere merges into space in the extremely thin exosphere. This is the upper limit of our atmosphere.troposphereWeatherstratospheremesospherethermosphere exosphere

Temperature The land and water absorb heat energy from the sun. Some of this energy warms the atmosphere above the surface. Earth’s surface heats up differently depending on the time of day. Copy picture on pg. 201

Temperature Different substances heat faster or slower. i.e. water heats up slower than land Grass does not hold heat very well Blacktop heats up fast and holds heat. It cools down quickly at night.

Wind Forms from convection currents because water and land heat up at different rates. Land heats faster, water slower. Winds can also change direction because the Earth is spinning. This is called the Coriolis effect. equator water experiment heating land and water

Air Pressure We are at the bottom of an ocean of air therefore air pressure is greatest at the surface.

Air Pressure Air has mass, when gravity pulls on the mass the air has weight. Air pressure is the weight of air pressing in all directions. Air pressure is measured by a barometer. weather and air pressure

Conditions to affect air pressure Water Vapor content Moist air has lower pressure Temperature Air gets warmer the pressure goes down Altitude The higher the altitude the less pressure

Weather When air pressure changes, there will be a change in weather. Rising air pressure = clear weather Falling air pressure = cloudy weather weather for today

Humidity Air holds a lot of water vapor. Water vapor in the air is called humidity. Water from oceans, lakes, rivers evaporate into the air. When the air is cold you can sometimes see the water vapor in the air. This is called fog. Humidity is measured with a hygrometer.

Precipitation Water vapor condenses to form liquid. Water droplets clump together to form drops. Clouds get heavy, drops fall to Earth because of gravity. Rainfall is measured with a rain gauge.

Clouds Clouds form when water vapor in the atmosphere condense and change to liquid. Clouds form in low air pressure. Three types of clouds 1.Cirrus (feathery or tufted) 2.Stratus (sheets or layers) 3.Cumulus( piled up) Nimbo- means precipitation

cumulus

Stratus

cirrus

Nimbostratus

Cumulonimbus aka thundercloud

cumulonimbus

Recipe for a cloud Water vapor + low pressure + dust(nuclei) = cloud

Weather Quickwrite Explain how temperature, air pressure, and humidity can work together to form the stratus clouds we see out there today.

Reasons why it rains a lot in the PNW 1.Cascade Mountain range- lots of runoff from the glaciers on the mountains. 2.Puget Sound – keeps temperature cold in summer, warmer in winter 3.Air from Canada is cold and moves down into Washington.

Cascade Mountain rain shadow

Why is it cold and dark? The Earth is rotating in space at a rate of 1,000 miles per hour. This gives us approximately a 24 hour day. The Earth is revolving around the Sun through space at an approximate speed of 66,000 m.p.h. This gives us a 365 1/4 day year.

Why don’t we feel the speed? We don’t feel these speeds because we are always moving at this speed. Just like we don’t feel gravity and air pressure. Try looking at a car on a highway that is traveling your same speed. If you just look at the car it will appear like you are not moving!

Leap Year It takes days for Earth to revolve around the Sun. How many.25 does it take to equal 1? Therefore, leap year is every 4 years.

Reason for the Seasons The reason why it is cold and dark here in the winter is because the Earth is tilted at 23.5°. The Sun hits the Earth differently depending on the time of year. Days are shorter in the winter and longer in the summer. We are the farthest from the sun in the summer, and closer in the winter. What causes Earth's seasons?

Moon The moon is 384,000 km or 235,000 mi. from Earth. It takes 2 seconds for sunlight to reflect off the moon and reach Earth. Moon has 1/6 the gravity compared to Earth. The pull of the moon causes tides in the Earth’s oceans.

Phases of Moon Wax on wane off.

Day 1 of cycle

Day 14

How many days after the full moon?

How many days?

What phase is next?

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