Unit 3 Chapter 10: Earth's Atmosphere and Oceans

Temperature gradients in Atmospheric Layers

Air temperature at any altitude depends on how much energy is being deposited there by various forms of radiation, both from the sky and from earth Where these layers come from. The temp. of air causes them to be where they are. Change comes from where the air/heat is being directed.

Earth's Atmosphere and Oceans

All things work together to keep the earth working—atmosphere, oceans, etc

Atmospheric pressure decreases with altitude since the air at the bottom gets more compressed by the weight of all the air at the top that it has to bear!

Atmosphere has layers of air Layers at bottom are high pressure Air pressure must balance the force of gravity in every layer

If the earth was shrunk to the size of an apple then our atmosphere would be as thin as the apple's skin

But without it there would be no life on Earth. There's no clear boundary to our atmosphere. 60 miles is probably the best number to use

Venus' slow rotation rate (243 days) means it has a very weak magnetic field and thus no protection from solar wind that can strip away atmospheres.

Early on Venus must have had oceans and rivers like earth, but the slow warming of the sun coupled with a 30% closer distance and no ozone layer caused its water to split into hydrogen and oxygen and was slowly stripped away by solar wind! With nothing to dissolve CO2 a runaway greenhouse effect was unavoidable!! On Venus, problem was that it doesn't rotate fast enough. No ozone layer means no water The oxygen that stays, absorbs by rock, so the water gets sucked up.

An aurora seen above Bear Lake, Alaska, USA

Have to go to the poles to see the Auroras in the winter time

A thick atmosphere made up of carbon dioxide, water vapor and methane is a recipe for a huge runaway greenhouse effect that would have baked Earth's surface into a dry crust with no liquid water.

However at that time the Sun was 30% cooler and most of the water vapor condensed into deep oceans! The carbon dioxide dissolved into the water and was then locked into carbonate rocks How did we get to poison gasses to what we have now with enough carbon dioxide? Our earth was cool enough at this time, sun was far enough away, and sun was cooler, it was able to vapor condensed water.

Chlorofluorocarbons (CFCs) from aerosol spray cans have been depleting the ozone layer creating a big hole. Banning of CFCs is starting to close this hole!

Human activity creates problems for life on earth. Chemicals we use have been hurting the ozone layer in our atmosphere

Interaction of sunlight with oxygen forms the ozone layer in the stratosphere, which protects us from harmful UV rays. These rays can also split water molecules into hydrogen and oxygen. Mars has no ozone layer which may have contributed to the loss of its oceans.

Hydrogen was lost to space and oxygen reacted with iron in Mars' soil to create reddish rust. Ozone comes from the interaction of sunlight to oxygen in the air UV rays can hurt our bodies and they could break apart H20. once they become separated, we could lose our water this way, which is why we are lucky to have an Ozone layer.

Earth's magnetic field deflects the solar wind and keeps it from kicking air molecules into space. As Mars' core lost its heat, its magnetic field vanished, and the solar wind stripped off its atmosphere!

Magnetosphere: protects us from solar wind We are largely protected by these objects because of our reflected field.

Gas pressure is caused by the rapid collision of gas molecules on the walls of the container. The more collisions per unit area the more the force exerted.

Molecules continuously collide

Where did our atmosphere come from? It all came from gases released from the volcanic activity that ejected molten rock buried deep in earth's interior.

Origin of our atmosphere began in the middle of the earth. As the inside of earth is heated and melts, the gas is released and what was released created our atmosphere.

Our atmosphere is like a bubble around us that protects us from harmful radiation and particles.

The air above 100 km is very very thin, but it still serves important functions! Our atmosphere is divided into layers

This just shows how lucky we are on Earth! Our oceans and rocks absorbed most of the carbon dioxide leaving just enough of it to keep us warm. The evolution of photosynthesizing bacteria created oxygen and the ozone layer which blocked out UV.

The cloud-rain cycle, photosynthesis and volcanism keep our atmosphere stable!The rain and the wind cycle is important to keep the right proportion of carbon dioxide and oxygen. A lot of carbon gets absorbed in rain, and rain becomes acidic. Which makes it easier for that rain to erode the land. When shells from animals fall off, they go under and make limestone. Oxygen comes from plants.

Greenhouse effect warms and moderates changes in the troposphere; the resulting convection creates the water cycle of evaporation, clouds & rain/snow

The right amount of the greenhouse gasses can be beneficial. It keeps air, moderates temp, and allows for liquid water and weather, etc.

Some of the solar wind particles get funneled into the polar regions creating the amazing Auroras!

This creates auroras/ northern lights.

The ionosphere provides a way for AM radio waves to be transmitted around the curvature of the earth without using a satellite. FM, UVF or TV waves are not reflected by this layer and pass right through.

What the benefits are of the ionosphere. Has been useful for radio communication

What two processes stopped the Earth from suffering the same fate as Venus where a runaway greenhouse effect has made life impossible

condensation of water and absorption of carbon dioxide

The boundaries between atmospheric layers are determined by changes in the [ Select ] ["pressure", "density", "temperature"] gradient with respect to the [ Select ] ["altitude", "area", "angle"] measured from the surface

temperature and altitude

Match the numbers on the left with the layers of the atmosphere on the right such that 1 matches the lowest layer, 2 matches the next higher layer and so on.

troposphere stratosphere mesosphere thermosphere exosphere

T or F The ozone hole that was created by the commercial use of CFCs in aerosol sprays and refrigerants is slowly starting to close.

true

Which type of radiation or particles are not stopped by any of the layers in our atmosphere?

visible light

An atmosphere is the layer of gas that surrounds a world. Earth's atmosphere has many benefits!

•Supplies oxygen for our breathing •Scatters light to make our skies bright and blue •Shields us from harmful rays from the sun •Shields us from being bombarded with meteorites •Makes rain which provides us with fresh water •Stops ocean waters from evaporating into space •Traps heat to create a comfortable temperature •Provides stability to our long term climate Our earth didn't start out with oxygen, early life didn't need it, but earth evolved to create creates/life that needs oxygen Our atmosphere gives color to the sky. If there's no atmosphere, it would be dark, regardless of the sun Weather keeps the water cycle going and helps with erosion. Our atmosphere traps heat and the pressure stops oceans from evaporating.