Atmosphere and Ocean
Weather is the day-to-day conditions of the atmosphere. It is caused by two main things:
unequal heating of the earth’s surface by the sun
earth’s rotation on its axis
El Nino – 3rd greatest cause of the weather
The unequal heating is caused by the earth’s tilt and curvature. The earth’s rotation causes wind and ocean currents. Some parts of the earth get hotter than others, and the heat is spread around by the atmosphere.
unequal heating causes vertical winds – hot air rising and cold air sinking
earth’s rotation causes horizontal or straight wind; earth rotates more than 1000 mph at the equator
Greenhouse effect; Yeah! See page 5
The atmosphere is the area of gases that surrounds the earth. It is held to earth by gravity. The air you breathe is part of the atmosphere. Air is a colorless, odorless, and tasteless mixture of gases. It is matter and takes up space (mass and volume). The atmosphere has the following ingredients:
Why is the sky blue if gas is invisible?
Atmosphere and Ocean - 2
Inert means that it will not chemically react with anything, won’t stick to anything
air on the ground – sea level
nitrogen - 78% of the atmosphere; inert gas; dilutes oxygen; mostly useless for animals in its pure form; bacteria “fix” nitrogen and turn it into nitrates and nitrites which are used by plants and animals to make proteins and DNA
Nitrogen cycle Yeah!
oxygen - 20% of the atmosphere; used by plants and animals for respiration - breathing and making food; includes ozone - a poisonous bluish form of oxygen with a strong odor; when ozone is produced on the ground from cars and factories, it is harmful and forms smog; from the middle to the top of the stratosphere is the ozone layer; the ozone layer acts like a shield that absorbs the sun’s ultraviolet (UV) energy which is destructive to life and causes cancer.
water vapor - varies between 1 to 4% of the atmosphere; heavy greenhouse gas; absorbs heat
argon - 1% of the atmosphere; inert gas (does not combine with anything); used in welding
carbon cycle Yeah!
carbon dioxide CO2 - 0.04% of the atmosphere; produced when materials burn (combustion) and when humans and animals breathe out (respiration); heavy greenhouse gas; absorbs heat
methane, hydrogen, CFC’s - trace greenhouse gases, less than 1 % of the atmosphere
trace = small amount
helium, neon, krypton, xenon, radon - other inert trace gases, less than 1 % of the atmosphere
Atmosphere and Ocean - 3
The atmosphere has five main layers which are identified mainly by their:
change in temperature – main way we tell them apart
pressure/density – how heavy are the gasses
If heavy gases sink, what do light gases do?
content – what types of gasses
The atmosphere extends out about 41,000 miles from earth’s surface to outer space, but most of the air is concentrated into the bottom two layers (troposphere and stratosphere - 0 to 30 miles above the ground) due to gravity. The layers beginning from the surface are:
troposphere, stratosphere
these two are the lower atmosphere
these two are the upper atmosphere
mesosphere, thermosphere
ionosphere = lower thermosphere; exosphere = upper thermosphere
Heavier gases separate from lighter ones and are near the surface. Different gases absorb different amounts and types of
solar energy. This is why the temperatures change through the layers.
From the ground, the temperature first decreases, then increases, then decreases, then increases, then decreases to outer space. Each layer has a top part,
called a pause, where the temperature stays the same for a distance.
Atmosphere and Ocean - 4
The troposphere is about 5-11 miles deep (26,000 to 60,000 ft). It is the layer closest to earth and contains most of the air. The troposphere is where weather happens. Temperatures drop as you move away from the earth (go higher). The top part of the troposphere is called the tropopause. It acts like a lid to keep water vapor and other heavy greenhouse gases in the troposphere. The temperature stops dropping and remains at -76°F.