Nitrogen Atmospheres, Ionospheres, Magnetospheres, 21, 23 October 2013!The Earth's Atmosphere: !1.The Earth's atmosphere went through several stages before it became the A.one we have now: !The Earth's first atmosphere was made of hydrogen, helium, methane, a.and ammonia which it inherited from the solar nebula when it congealed 4.5 billion years ago. !Earth's hydrogen and helium atmosphere became a carbon dioxide b.atmosphere due to its mass and volcanism.!The earth's mass was too small to have enough gravity to hold onto 1.hydrogen and helium, so they escaped into the solar system. !The escape velocity of each atom of hydrogen and helium was A.more than the earth's gravity pulling on it. !At the same time, the volcanoes of the Earth were erupting, filling the 2.atmosphere with hydrogen, sulfur, and phosphorous oxides. !Volcanism and Earthquakes were more abundant in the first billion A.years of the earth than they are now. !The oxides of hydrogen (H2O) filled the lowlands on earth, and B.became seas and oceans. !The carbon dioxides filled the Earth's atmosphere. !C.Carbon dioxide was the majority gas in the atmosphere by half a a.billion to a billion years after the Earth first solidified.!The biochemical processes of life that developed in the warm, shallow c.seas of earth replaced the Earth's carbon dioxide atmosphere with one that is predominantly oxygen and nitrogen. !Some of these early life forms used photosynthesis, which involves 1.taking in water and carbon dioxide and to create carbohydrates and hydrocarbons. A bi-product of these reactions is oxygen, which took carbon's place in the atmosphere.!The exact percentage of oxygen in the atmosphere has varied over 2.billions of years. It peaked around 20-30%, and it is currently about 19%. !This oxygen became the fuel source for animals, who take in the 3.oxygen, attach it to carbon from carbohydrates and breathe out carbon dioxide. !The processes of these two types of organisms form a cycle in the air: 4.organisms that use photosynthesis take in carbon dioxide to create oxygen, which other organism transform into carbon dioxide.!The types of organisms that photosynthesize are plants and A.microorganisms.!The organisms which take in oxygen and release carbon dioxide B.are animals. !The exact classification of the organisms with these processes C.continuously changes as scientists learn more about the organisms.!Since the rate of photosynthesis far outstrips the rate that animals 5.change oxygen into carbon dioxide, the atmosphere of Earth remains mostly oxygen. !The processes animals use is much less efficient than A.photosynthesis.!The earth's atmosphere has lots of different layers in it:!B.These layers have turbulence which is called weather at lower levels (and a.different names at higher levels).!This turbulence is caused by lots of pockets and layers of air moving 1.around in the atmosphere. !The air organisms breathe is in the troposphere. !b.Airplanes fly in the boundary between the troposphere and c.stratosphere.!There is O3(ozone) on top of the stratosphere in the ozone layer, but d.this is not the only chemical there (there is also nitrogen). !The mesosphere and ionosphere are above the ozone layers.!e.The Earth's air is mostly nitrogen and oxygen, with trace amounts of other C.chemicals: !The earth's air is about 70-80% nitrogen. !a.No one really talks about it because it is almost inert (it is not 1.involved in a lot of chemical reactions. !The layers in this diagram are somewhat exaggerated, and it is not to scale.Neon comprises about 1% of the atmosphere and is also almost b.completely inert. !The carbon dioxide, water, and oxygen in the earth's atmosphere are c.also relatively abundant and involved in a lot more chemical reactions.!There are trends regarding the global distribution and movement of air on D.Earth: !The air around the equator doesn't move much. !a.At California's latitude the dominant air motion is from west to east. !b.Closer to the tropics, the dominant air motion is from east to west.!c.Clouds:!E.Cumulous clouds: the fluffy, fair weather clouds of summer.!a.They form when sunlight heats the ground, heating the air around it, 1.which becomes less dense. Because the air is less dense, it rises.!The ground is usually hot enough in the afternoon to cause a lot of A.cumulous clouds to form. Less clouds form in the morning, and none at night.!Cumulous clouds with the sharpest edges are the ones most recently 2.formed.!If you happen upon a sharped edged cloud in a plane, you should A.stay away from it. The rapidly moving air that formed the cloud is still there. !The edges of cumulous clouds get softer as they age. !B.Water droplet clouds:!b.Usually called water vapor clouds, but actual water vapor is 1.transparent, and what you actually see in clouds are tiny droplets of water.!You have experienced this type of cloud if you have every been in fog.!2.Stratum clouds: !c.Clouds that lie in a flat layer.!1.The word "stratum" means flat layer.!2.Anvil clouds: !d.Sometimes clouds convect vigorously, and form anvil cloud, so called 1.because their flat tops resemble a blacksmith's anvil. !As the air in these clouds rises, it hits a layer of air that is less A.dense than it is and cannot rise any further. Instead, it just spreads out at the top. !Low lying clouds: !e.Thick, opaque fog that lies on the ground. !1.It can be as high as twenty meters, and as low as your shins. !A.You can often find this type of fog in valleys and bays.!B.Low lying clouds (fog) in the San Francisco bay sloshes back and forth 2.toward San Francisco and Berkley with a period of 40 minutes.!No one has studied this.!A.Verga: !f.A rain cloud where rain falls, but evaporates when it hits a layer of air 1.with low humidity before it can reach the ground.!Cirrus clouds: clouds made out of frozen water droplets.!g.Ice crystals in these clouds come in several different shapes, but the 1.predominant shape is a flat hexagon. It looks like a thin slice of a pencil, so it is called a "pencil crystal."!Sometimes, there is an overall organization to clouds that you can only h.see from above them in a plane or space craft. !There are often different kinds of clouds in the same sky.!i.Books claim that clouds are pretty much the same reflectivity, only j.looking dark if you are seeing them from an odd angle. Real world evidence seems to contradict this.!In a picture of a cloud from a steam vent, you can see the steam 1.changing from white
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