Atm Ocn 100 Edition 1nd Lecture 26 Outline of Last Lecture I Review Sheet Questions and Answers ones we went over in class Outline of Current Lecture II Reminders III Current Weather IV General Circulation V SSEC Global Satellite and Surface Temperature VI Solar Absorbed Minus IR Emitted VII Heat Transport VIII Global Atmospheric Circulation IX Rotation produces banding of the General Circulation X 3 Celled General Circulation XI 3 Celled Hemispheric Circulations Current Lecture Reminders Homework Due Wednesday November 26 2012 TYU Ch 5 1 2 3 8 9 13 TYU Ch 23 1 2 3 4 5 6 7 8 10 13 19 TYPSS Ch 5 3 TYPSS Ch 23 none TYU Ch 24 1 5 7 9 10 14 18 19 22 23 25 TYPSS Ch 24 4 Current Weather There is a strong weather system moving toward our area this week There is a strong cyclone centered over Northeastern Colorado There is also a band which is a snow pattern just north of this cyclone The storm really formed out of nothing so it was really hard to predict It started forming out of energy that moved out of the pacific from last week It wasn t till this week that we saw a Jetstream pop up as a result of this energy We can see a classic configuration The isobars in green are kinked along a trough to the east The kink is a result of the isothermal pattern it s the warm front associated with the storm The warm front is just to our south We are north of the surface warm frontal position We are not as cold as northern Wisconsin because they have more isotherms Upper airflow at 850 mb is from a southerly component The warm front is like a ramp of cold air that is sloped up to the north And when we have winds from the south the air is lifted up over the ramp When warm air comes from south over the ramp it is lifted This is a forced lifting situation it is not unstable air This air is not forming thunderstorm air is being forcible lifted by shear winds at different levels To our north there is going to be heavy snow at 0z This is almost January like temperatures This is from the tropical system that created a strong circulation that is creating cold air out of air that isn t so cold by lifting it We won t get a ton of snow from this storm We will get very cold air tomorrow morning though It will not be as cold at 96 hours Winds in the Northern Pacific have a Northerly component and a Southerly component And they have an Easterly component General Circulation The general circulation of the planet is what drives weather This is a picture of the Earth There is a band of clouds going across the Atlantic this would be the inner tropical convergence zone The picture is of winter because the inner tropical convergence zone is South of the equator SSEC Global Satellite and Surface Temperature This is another picture of a view of the cloud pattern They are available on websites We can see different fronts from this picture Solar Absorbed Minus IR Emitted Sun shines on the Earth and the sun is more direct on the equator then other latitudes The sun shining on the earth is what heats the ground and what heats the earth Earth only receives the warmth at one side at a time Earth balances that heat by radiating energy to space this happens everywhere Even if that area is not getting heat from the sun at the moment To do this energy has to move around Since the sun shines primarily in certain areas some areas get more energy than they radiate and some radiate more energy then they receive In order to do this the energy has to be moved around The result is a general circulation that moves air around to maintain that balance The global energy balance also varies with longitude primary due to the differences of land water and elevation We can look at the surplus and deficit of energy in this picture The surplus is in the equator And the two sides have a deficit The amount of energy loss occurs like this because it has to do with temperature If it wasn t for weather we might expect that the emission of radiation curve would follow the solar radiation in which case the poles would get very cold The poles are kept from getting to cold by weather Weather maintains the cold like this The ocean currents actually move more energy then the atmosphere Heat Transport Because there is an excess of heat at the equator and an deficit of heat at the poles transport of heat from the tropics to the polar regions must occur Atmospheric heat transport through the general circulation Ocean heat transport through ocean currents Global Atmospheric Circulation To transport heat we might image a meridional north south circulation with cold air flowing from the pole to the equator at the surface and vice versa aloft Such a circulation cannot exist because Coriolis prevents it But if you bring air to the pole there will be a very strong wind speed which we cannot do As air tries to rise and move toward the pole it has to turn toward the right and can never get passed a certain degrees latitude The rotation of the earth prevents the total circulation to happen instead it breaks up into cellular patterns Rotation produces banding of the General Circulation Other planets have rings and bands around them They spin faster than the Earth The wind would turn to the right in those planets even more rapidly than it does on the Earth So the result is that they have banded type of weather patterns where the wind only moves so far before it has to stop The Earth is no exception we also have a banded circulation 3 Celled General Circulation At the poles we have the polar high or the polar cell And this cell has cold air sinking at the poles and going to the south It then goes to the right but doesn t get real strong because of friction There is a polar cell in each hemisphere and in between is the so called ferrel cell which is made up of cyclones that have circulation that on the average produce We have Westerlies and then we also have the Northeast trades This is just a picture of different cells that occur around the globe Also the different wind types Winds are not very strong when you get the region of convergence along tropical convergence zone You don t have systematic winds from one direction or another Another picture that show wind systems by drawing contours Can see a subtropical high and Westerlies And the other side shows the same thing except it s a zonal average or uniform picture of the east west The reality is though that it is broken up into cells in some places trade is stronger …