Earth Science Review Video 16 Weather Unit 5 Global Local Winds

hi everyone welcome to the next video on whether this is going to be talking about global and local wins all right so to start off it would be good if you knew what wind was it's the movement of air from high pressure to low pressure so the only way to have wind is to have an area of high pressure and an area of low pressure and generally the bigger the difference between them the faster the winds going to move so if there's large difference in the pressure amounts you're gonna get your fastest winds now wind is actually caused by the fact that the earth is unequally heated so if you remember back to astronomy the earth is on tilt and this is gonna cause different sections of the earth to get different amount of insulation which this is like the chain of effect here if you have unequal heating you're gonna have places with different temperatures and if you remember from the air-pressure video the last one different temperatures causes there to be different pressure remember warm is low-pressure and cooler is higher pressure which means if you have different pressure that's going to give you your movement of air because the air is gonna move from the high pressure to the low pressure that your wind so this is your chain of effect without the unequal heating you wouldn't have the different temperatures which means you wouldn't have different pressures which means you probably wouldn't have that much wind so this is generally what how it happens now on your reference table page 14 this is going to be your global wind picture so I'm just gonna run through what think is the most important things to know here this is zero degrees which is the equator so it's really warm here and if it's warm that air is gonna rise off of the earth creating low pressure here and then these convection cards are gonna bring the air to both sides and then they're gonna sink down here and here so if this is sinking that means it's high pressure which means it's probably dry which is labeled for you and the same thing happens here and this pattern actually repeats so this is another low pressure here another high pressure at the poles and then low pressure down here and high pressure at the South Pole so it's pattern and the reason the pattern started is pretty much from the equator and the poles the poles are cold so you're gonna have sinking up here and at the South Pole and the equator is warm couple other things to notice about this is that we live here where put this we're at 42 degrees north so we're between 30 and 60 which means we are in this wind belt which are the southwesterly where they're called the prevailing southwesterly so this makes all of our weather go towards the Northeast if you look at the arrows the only other thing would say to know about this chart is if the arrows are coming together this is called converging and if the the hours are going apart that's called diverging so for example the air converges at the equator see the hours are coming together another example is the air diverges at the surface of 30 degrees north so you got an arrow going this way and an hour going this way so they can ask sort of like if the air is converging or diverging at different spots essentially okay the only other thing can mention right now which we're gonna get ahead we're gonna do eventually this area is dry this area has moisture and this area is dry that's why we have deserts here and here and rainforests here generally and I'll show you picture of what that looks like little later there's this belt of wind in the troposphere called the Jetstream and you might know about this because if you are flying with the Jetstream and you go on flight your flight time is normally less because it's this giant air mass of wind and like 30,000 feet it says it even here on this newscast that's where planes normally fly so if you're going with it you go faster if you're going against it you generally go slower but this is also part of the reason why all the clouds in the air is also moving towards the Northeast across the United States so they're sort of related and the jet stream can shift throughout the year so sometimes it's more north and sometimes it's more south which will change our weather this is just an easier diagram to look at than this one so if you look at this one here's the United States right here we live around here so the prevailing westerlies is our giant wind belt meaning all of our weather goes to the Northeast and the other good thing about this is that normally we have hurricanes that come up towards Florida over here so sometimes they steer away to hurricanes this is picture of where the deserts and the rainforests are so you could see around 30 north this is dry on that other chart and so is this so you get your deserts and deserts and then over here at the equator this is your moisture area by the equator to get all the rainforests the last thing about global winds that is important is that the ocean currents and we talked about this page already the direction is caused by the the global wind patterns and by the Coriolis effect which is causing the winds and the water to curve okay so this is more of local winds so here's picture of the beach this is the first type of wind phenomena that you're gonna get it's called sea breeze and it happens when the sun's out generally during the day so if you remember from the energy unit water has high specific heat that means it takes really long time to heat up and cool down and the land has low specific heat that means it heats up and cools down pretty quickly so what happens during the day is that the sand gets really hot and the water stays cool so warm air is going to rise and since it rises and it's warm you're gonna get low pressure developing over the sand now the opposite is going to be happening over the water because it's cooler so the air is gonna be sinking here and it's cool so you're gonna get high pressure over here and what's gonna happen is the air from the high pressure is going to move to the low pressure this creates the wind and this is called sea breeze and the reason it's called the Seabreeze is because it comes from the sea wind is named from where it comes from now you're gonna get the opposite effect at night for land breeze to happen you're gonna need it to be nighttime and at night remember the water has high specific heat so it takes longer to cool down at night so the water is actually going to be warmer than the land at night the land is gonna cool down very rapidly because it has such low specific heat so since your temperatures switch your pressures will also switch warmer low pressure rise cooler high pressure sink and you get this convection loop that happens and your air goes from high pressure to low pressure so you get land breeze because the breeze comes from the land so this is phenomena that occurs because of the wind because of the pressure and because of the temperature so you feel it when you go to the beach it's pretty awesome alright and the last little thing for this video is going to be determining where fast winds are on map full of isobars so these are ISIL lines that measure pressure if the isobars are close together that means it's high gradient which means that the pressure is changing very quickly over short distance so this area here this is high gradient it's lot of change over small distance and if there's high gradient that means it there is fast wind so when the lines are close together you get your fastest wind and normally you would see that near low pressure because it's stormy area stormy cloudy precipitation so if you look by the high pressure there's normally not lines close together over here again and they're windy area fast wind here slow wind where they're not close together it's directly related to the steepness of contour lines remember we said for contour maps that when the lines are close together it's steep slope like cliff wall is the same premise lot except for pressure when the lines are close together it's fast wind ok so let's see if we can get some questions right question one in which cross-section which just means side view do the arrows represent the most probable direction of air movement over land and water at coast on hot sunny summer afternoon so if it's afternoon and it's hot and sunny you're gonna get sea breeze remember sea breeze means the wind is coming from the sea so look at find the hours where the hours are coming from the is the best answer is going here this is land breeze because the breeze is coming from the land and this doesn't happen and that doesn't happen see they're always going to be this one or this one number two why are most beach is often considerably cooler than nearby inland locations on hot summer afternoons that's because water takes time to heat up and cool down because it has high specific heat so you want to pick something like that sea breeze develops due to the higher specific heat of water and again your key word there hot summer afternoon sea breeze always happens during the day and land breeze happens at night number three we got our ocean sorry our global wind patterns which climatic condition exists where the trade winds around the equator converge well here's where they converge remember these two hours are going to meet up with these two hours so what's gonna happen there well it says wet so we can get any dries out now then you got to think the Equator is it warm or cold it is warm see best answer number four which wind belt do most storms move towards the Northeast well in the United States remember the prevailing southwesterly that's our wind belt and the southwesterly move everything to the northeast because they come from the southwest now you can also just use this chart here and you can look and look at the arrows between the latitudes and that is the only one where they're coming from the Southwest blowing towards the Northeast so you would just use your reference table on that question okay number five from the eastern United States the change of the polar front Jetstream from the summer position which looks like it says here summer to the winter position so the Jetstream moved down what would this cause well immediately you could see the wind speed went from 60 miles an hour to 125 so the storms are gonna move faster if the wind is blowing further so this one that says it's moving more slowly that's out this one is out and if this polar jet stream polar means cold that means cooler temperatures are gonna be farther south now because the whole thing moved down so DS your best answer now that question was mainly being able to interpret the picture you really didn't have to know anything content-wise you just had to look at the picture number six which location most likely recorded the highest wind speed okay remember isobars when they're closed that means you're gonna have high gradient which means you're gonna have fast winds so it looks like be as I'm where they're really close so that's the best answer number seven wind moves from wind is always high to low pressure beat number eight the arrows show the most likely path where which two systems will move so which way is the and the probably going to go up there over the United States remember we are in the prevailing southwesterly so all of our weather is going to go towards the Northeast so your best answer is and lost my mouse lost my little pen so everything's gonna go this way always deep number nine we got that sea breeze will picture the air pressure at the surface few miles from the shore so like over here is most likely what well remember to get breeze or to get wind you need to go from high pressure to low pressure so you want if this is the low you want this temp pressure to be higher so it's got to be 1017 if it was 1013 there would be no wind and if it was beer hey that means that the wind would go the other way and the last one so they got City pressures over the course of four days city pressures over the course of four days the wind speed in the region between and was probably greatest on which day you want the one where there the biggest difference so the ones with the biggest difference is going to be it looks like this one's like about to millibars difference this one's about 11 this one's about 3 and this one's about zero so day three since you have your biggest difference you will have your fastest wins all right so hope that was helpful again just want to tell you that don't think that these videos should be complete replacement of studying your notes and you know whatever asking your teacher questions and stuff like that but it should be used on on the side of the normal things that you would normally do not the only thing that you end up doing alright all right good luck see you on the next one