The Atmosphere

[Music] hi it's Mr Anderson and this is environmental science video 4 it's on the atmosphere which is the gas covering on our planet remember we live in the atmosphere and as Society gets larger we're pushing against these planetary boundaries and since the economy is pushing us towards that the economy is going to have to bring us back and a story that relates to this is the story of stratospheric ozone we call that good ozone it's made of three oxygen at and it surrounds the planet and it protects us from harmful UV radiation but in the

60s and 70s we were producing huge amount of CFCs the CFC is a this is an example it's a carbon Florine three chlorine molecules it would also go into the atmosphere get hit by UV radiation kicks off a chlorine binds to an oxygen atom and now we've destroyed the ozone and so you've probably heard of this hole in the ozone this one's right here over Antarctica what's going to happen if we don't have that protective ozone increasing cancer damage to crops and so this is a really big deal and so how do we solve that

problem industry is going to say rightly so we shouldn't have to bear the cost of all of this it's going to cost us you know Millions if not billion dollars we're going to lose jobs but eventually the consensus came around and government said we're going to have to solve this problem and in 1987 they signed on to What's called the Montreal protocol where they ban cfc's that's led to a decrease in cfc's increase now of ozone it'll probably return to its original Levels by 20 2050 and so this is a great example of how governments

can bind together to form a treaty that's incredibly successful and so the atmosphere surrounds the earth scientists break it into a number of different spheres we've got the tropo Strat meso Thermo and exosphere now we live in the troposphere and that protective ozone is going to be found right at this boundary between the two weather is going to be the current state of our atmosphere and over a long period of time we call that climate which is due to the tilt of our axis and where we are in the orbit around the Sun and so

due to our location we get Seasons we're pointed towards the sun in the summer and away from the sun in the winter but also since we're a sphere we're starting to get unequal heating of the planet and those convection currents lead to cells in the atmosphere got things like the Hadley cell the feral cell and what those are doing is moving the atmosphere around on our planet now we also have a spinning planet and that creates something called the Coriolis effect and so it spins in a characteristic way and so the combination of these two

lead to atmospheric circulation it's moving the weather around on our planet now the oceans also affect our our climate and as the atmosphere moves around it starts to move the oceans and so we get these ocean currents which are shaping our climate and an example of all these things coming together is elino or Enzo the elino southern oscillation which we'll talk about in a little bit and so the atmosphere is a series of spheres that surround our planet this is not to scale but the lowest one's going to be the troposphere that's where our mountains

are that's where we are when you're on a jet you'll you're still within the troposphere above that we're going to have the stratosphere so weather balloons will move into that area if we look at ozone right here so this is going to be ozone right at the surface of the planet we're going to have some bad ozone we call that tropospheric or smog ozone that can be damaging to us we'll talk about that later but as we move up in the troposphere into the stratosphere we're going to have a huge increase in that ozone layer

that's that prot effective layer around us above the stratosphere we have the mesosphere that's where meteors are burning up above that we have where the Aurora are that's going to be the thermosphere and then finally we're bordering space this is going to be the exosphere up here now what are some conditions within the whole atmosphere we're going to increase density the closer we get to the Earth because there's higher gravitational pole the closer we are now what's the atmosphere like today that's weather raining is it sunny what's the temperature and that's important but what's more

important is climate that's going to be weather over a long period of time and if we look at this biome mat you start to see some patterns and so if you look right here we're going to have a bunch of tropical rainforest we'll have deserts right here and if I put the latitudes over this the one thing I'm always surprised is how low the equator is so if we put this in at at 0 degrees then 30 and then 60 real patterns start to emerge so right here along the Equator we're going to have all

of this precipitation rain forest are going to be found there but look right here at 30° above and below or northern and southern we're going to have these deserts and then we're going to have these big boreal forests out here and so all of that has to do with where the Earth is in Orbit and also the tilt of the earth and so we get Seasons due to the tilt of the Earth as it moves around the Sun this is obviously not to scale but as the northern hemisphere is pointed towards the sun look here

on the North Pole it's going to be 24 hours of daylight in the winter it's going to be 24 hours of night um right here we'd have the E Equinox es but depending on are we pointed towards the sun summer or away from the Sun winter it's going to affect our our weather and therefore our climate remember everything would be reversed if we were in the southern hemisphere we also get unequal heating so if I again not to scale but if I were to put an atmosphere in here as the sun's Rays come in here

at this part it's going for through a very small amount of the atmosphere so we don't lose much heat but up here we're going through more of the atmosphere it's going to be colder near the top if we remove that and just look at the light itself right here here this amount of of sun rays is all concentrated on this very small surface area but up here near the North Pole it's spread out over a long surface area a large surface area so it's going to be cooler near the poles now remember as we move

around the Sun that axis is going to tilt back and forth and so that's going to affect this unequal Heating and the last thing that affects unequal heating is the albo of the earth it's it's our reflectiveness so as the sunlight hits the snow for example it's going to be reflected off but if it hits vegetation or or water for example we're going to have a different amount of albo so it's a combination of all of these things that creates climate first one that's most important are going to be the cells on our planet what

that means is right here at the equator we're heating up the air most right here along this point and so what we get are these convection cells so we heat up the air and it's moving up it becomes less dense and it's moving up now what quickly happens to it is it actually cools down and so as it cools down eventually reach something called the dupoint that's where it can't hold water anymore and we're going to have the formation of clouds and then we're going to have precipitation have you ever wondered why the bottoms of

all the clouds line up it's because we're cooling the air as it moves up until we hit that due point now what happens eventually is that that atmosphere is going to start to drop down again and so we have another cell here and another cell here so if we look at the equator we're going to have a huge amount of precipitation here but remember at around 30° all that air is moving down it actually is being heated up and we're not going to have much precipitation there or at the pole itself and so these will

be affected by the tilt of the earth as well and so cells are important to understand so I've turned the Earth on its side so this is now equator North Pole so if we move from the equator to the North Pole the first thing we see is a huge amount of convection near the equator and you're going to have a huge amount of weather right here it'll eventually move up and then it slides down as it as it moves down it's going to actually heat up and we're not going to have much precipitation at 30°

we call this first one the Hadley cell it's named in honor of the person who proposed it now if we keep moving so again we're moving down to this next cell right here we're also going to have convection current that's moving the air up at 60° north latitude and South and then eventually it's going to be heated as it moves down so we're going to have more precipitation here we call this the feral cell it's named in honor of the person who osed it and then finally we have a Polar cell it's named in honor

of no it's not it's just near the pole and so the other thing that contributes to uh atmospheric circulation is Coriolis effect so again the Earth is spinning think of it like a a record player spinning around if I were to tape something to the record player like this cone let's say it represents the mountains as the record player spins the mountains are just going to move around with the Earth we're moving on the Earth right now we we are not affected by it because we're connected to the Earth but let's say I put something

on that record player that's movable let's say I put a marble on it and now I spin it watch what happens to the marble it will be deflected off and if I were to trace that path it moves like this and so if you think about it on the north side of the record it's going to be moving clockwise but if you could move underneath the record it would actually be moving counterclockwise and so the Earth is like that record player it's a sphere obviously but in the northern hemisphere it's going to move clockwise in

the southern hemisphere it's going to move counterclockwise and so the combination of these cells and the coris effect creates the weather patterns that we have on our planet so you can see here are the three cells hadly feral and polar cells right here but we also have the movement due to the spin of the earth and so right here near near the equator we're going to have what are called the trade winds they're always going to be moving in this direction due to the spin of the earth both in the Southern and Northern Hemisphere they're

all moving in this direction if we move north or south we're going to start to get what are called the Westerly it's going to be moving in this direction now as that atmosphere pushes on the ocean we get Oceanic currents we're getting these trade winds and then we're getting the Westerly coming back as that blows on the ocean we get this Gulf Stream that's moving the ocean we also start to get deep currents in the ocean due to heat but also due to changes in salinity and so this ocean is moving around as a consequence

of not only salt but also the temperature and so tying these all together something you should be very familiar with is o or the El Nino Southern oscillation and what really is going on is it's just moving back and forth between el Nino and linia and so this is a graph that shows this oscillation from 1880 to 2010 and so it's in a neutral position it will then move towards elino and then it'll move back to linia and then it'll move to elino sometimes it's not a very big El Nino sometimes it's a very big

elinia or linia it just moves back and forth so it's oscillating you can see that in the record but you should be asking yourself what causes it and so let's go look and so what here we're looking at is the Pacific Ocean so this is the Pacific Ocean right here this would be Central America South America North America and then all the way on the other side of the Pacific is going to be Australia over here and so what we have is a walker circulation remember the trade winds are blowing the wind in this direction

along the Equator and as they do that what we get is a circulation pattern that moves the ocean water cold water here it's pushing the warm water to the Western Pacific this is the neutral or the normal position now what can happen watch what happens to the Walker circulation as I move us into a linia so as I move us into linia watch what happens to the Walker circulation we have greater trade winds and increase in trade winds is pushing more of that warm water over here towards Australia so we're going to get it that

weather way over here it's going to be cooler here around central America now watch what happens when the Walker circulation starts to die off now we have El Nino and so we don't have that huge push and so we're going to have warm weather it actually starts to move in the opposite direction and so this ocean is now going to affect the atmosphere and it's going to affect Humanity as well so could you fill in this concept map I would encourage you to pause the video and give it a try and then I'll tell you

the answers um first thing could you tell me the levels inside the atmosphere it's troposphere Strat osphere mesosphere thermosphere so that should be here exosphere my nemonic for this is try some milk then eggs that's a good way to remember the layers right here we'd have that important Ozone gas which can be bad if we have it way down here in the troposphere whether over a long period of time is going to be the climate which is affected by the tilt of the earth and and the Sun and the location of the sun um so

we get Seasons from that we also get unequal heating which cre creates these convection cells Hadley cell feral cell polar cell the spin of the earth creates the Coriolis effect and also ocean can impact that so hopefully you got all those right and I hope that was helpful [Music]