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Tuesday Oct 26th SIT WITH YOUR GROUP TODAY TOPIC # 12 HOW CLIMATE WORKS I-3 IS DUE TODAY! Please deposit your I-3 WORKSHEET [STAPLED!] at the FRONT OF THE CLASSROOM according to GROUP # (NOTE: we will also accept Worksheets on Thursday if you don’t have yours today or need it to finish your write-up tonight.) The I-3 Write-Up is due in D2L Dropbox by 11:59 pm tonight. As soon as you come in today, get your GROUP FOLDER & finish up G-3 if your group is not quite done . . . . RQ-6 is due on THURSDAY Oct 28th Warning: there is LOTS of reading for this one! TEST #3 is scheduled for a week from TODAY. . . . . The Top 10 List will be posted by Friday. WRAP –UP of G-3 ASSIGNMENT Applying the Energy Balance Terms Your task is to decide which component or components working together are most directly related to or responsible for the observed phenomenon. # 1 – #12 : Left side of equation # 13 - #15: Right side of equation p 53 THE G-3 ANSWERS The LEFT side of the equation: 1. gases of atmosphere scatter shorter blue wavelengths 3. 2. 4. Noon: more 5. + & dusk: more together = the Greenhouse Effect 6. (dust, thicker atmosphere scatters longer red/orange wavelengths) 7. radiates day & night; camera senses IR 8. 9. leads to distinct shadows, while diffuse SW radiation does not 10. All wavelengths of visible part of spectrum are scattered & transmitted in a colored spectrum by raindrops 11. Attempt to increase absorption & reduce into eyes; reduces glare 12. More is absorbed, leads to more which can then warm up car The RIGHT Side of the Equation: 13. H Hot air (less dense than surrounding cool air) rises in a convection current & lifts balloon 14. Wet mud evaporates from pig & cools him: LE also heat from pig’s body is conducted into soil: 15. June is hot & dry in Tucson. Dry, hot air can “hold” more water vapor, so water in cooler pads is evaporated easily. Hence more energy goes into instead of This cools the house! LE H G Topic # 12 How Climate Works A “Primer” on How the Energy Balance Drives Atmospheric & Oceanic Circulation, Natural Climatic Processes pp 63-68 in Class Notes How do we get energy from this . . . . . . . . to drive this ? . . . . or this ? http://www.vets.ucar.edu/vg/T341/index.shtml . . . .which leads to Global Climatic Regions: . . . .and CHANGES in these regions! Hotter! Drier! Wetter! from Dire Predictions text It all happens because of changes in the RADIATION / ENERGY BALANCE ! “Radiation Balance” part All components are referring to modes of heat energy transfer or heat energy storage involving matter All components are referring to electromagnetic radiation “Energy Balance” part Start out here, with energy from the SUN radiated to Earth and so forth . . . “Radiation Balance” part = The is then able to be used in thermal energy “heat transfer” “Energy Balance” part processes which manifest themselves as weather & climate! Thermal Energy Review Heat (def) = the thermal energy that is transferred from one body to another because of a temperature difference. • Sensible Heat transfer (H) • Latent Heat transfer (LE) plus (after transfer) thermal energy can be STORED (G) Review ENERGY IN THE EARTH-ATMOSPHERE SYSTEM Ultimate source of energy is the SUN (SW) After absorption of SW, LW energy is radiated in & out by EARTH & Atmosphere Any NET (leftover) energy Goes into the HEAT TRANSFER processes that drive WEATHER & CLIMATE ! The Earth [as viewed from space] . . . has the organized, selfcontained look of a live creature, full of information, marvelously skilled in handling the sun. ~ Lewis Thomas LINKING THE ENERGY BALANCE TO ATMOSPHERIC CIRCULATION . . . We’ll start with the SUN (SOLAR INSOLATION) IN – SOL- ATION = Amount of incoming solar energy received by a point on Earth’s surface p 63 To drive the circulation, the initial source of energy is from the Sun: EARTHSUN Not to scale! Relationships 4 Things to Know about Earth-Sun Relationships: 1) Earth orbits Sun in one year 2) Orbit is not a perfect circle ( = an ellipse ) 3) Earth’s orbit around Sun can be “traced” on a plane (“Plane of the Ecliptic” – plane passes thru the center of Sun & Earth) 4) Earth’s axis tilts 23.5 from a to the “Plane of The Ecliptic” http://mesoscale.agron.iastate.edu/agron206/animations/01_EarthSun.html These 4 Earth-Sun Properties lead to: the 2 factors that determine the AMOUNT OF SOLAR INSOLATION as the seasons progress: (1) INTENSITY of sun’s rays (perpendicular to surface = more intense) (2) DURATION of daily insolation (longer day length = more insolation) p 63 Zenith point changes with latitude A useful term: ZENITH = The point directly overhead INTENSITY is greatest at any spot on Earth when sun is closest to the ZENITH! QUICKIE LATITUDE REVIEW: 90 N 66.5 N 23.5 N 0 23.5 S 66.5 S 90 S EARTH-SUN RELATIONSHIPS & The SEASONS: VIEW THE ANIMATION: http://mesoscale.agron.iastate.edu/agron206/animations/01_EarthSun.html JUNE SOLSTICE As viewed from one side of Sun JUNE SOLSTICE As viewed from the other side of the Sun JUNE SOLSTICE p 63 JUNE SOLSTICE 24 hours of sunlight Most intense solar radiation p 63 MARCH EQUINOX Equinox = “equal night” p 79 SEPTEMBER EQUINOX different seasonal position in orbit . . . . . . but same latitudinal insolation as March Equinox MARCH & SEPTEMBER EQUINOXES 12 hours of sunlight Most intense solar radiation p 63 DECEMBER SOLSTICE DECEMBER SOLSTICE 24 hours of darkness Most intense solar radiation p 63 http://mesoscale.agron.iastate.edu/agron206/animations/01_EarthSun.html Recap THE RADIATION BALANCE & THE GENERAL CIRCULATION OF THE ATMOSPHERE p 64 HOW IT ALL FITS TOGETHER: Over the course of a year . . . The amount of INCOMING SW (Insolation) absorbed by EARTH varies by LATITUDE (MORE comes in near the Equator, less near the Poles) LOW LATITUDES absorb MORE energy than HIGH LATITUDES The amount of outgoing TERRESTRIAL LW / IR varies by latitude too -- MORE LW / IR is emitted at warmer LOW LATITUDES, LESS in cooler HIGH LATITUDES HOWEVER . . . p 64 The EQUATOR-POLE DIFFERENCES of what goes OUT from the EARTH are less than the EQUATOR-POLE DIFFERENCES of what comes IN from the SUN p 64 LESS SW coming in BUT the amount of outgoing LW is only slightly different from latitude to latitude & Equator to Pole SW in < LW out MORE SW coming in SW in > LW out p 64 The result is a NET SURPLUS of energy in the low latitudes & a NET DEFICIT in the high latitudes p 64 POLE EQUATOR POLE Now lets look at a Pole to Pole Transect p 64 Net radiation deficit Net radiation surplus Net radiation deficit What do the black & gray areas represent? (at top of atmosphere) p 64 http://geography.uoregon.edu/envchange/clim_animations/ Global-scale air motions are driven by thermal differences: Northern Hemisphere COLD POLAR REGIONS EQUATOR Southern Hemisphere HOT TROPICS COLD POLAR REGIONS COLD POLAR REGIONS HOT TROPICS From SGC-I Chapter 4 COLD POLAR REGIONS cold polar air vs. warm low lat air sinking dry subtropical air rising tropical warm, moist air sinking dry subtropical air warm low lat air vs. cold polar air LOW PRESSURE AREAS: Hot surface Rising air expansion and cooling of air, and condensation of water vapor clouds, and possibly precipitation . . . HUMID REGIONS How do H2O droplets in warm, tropical clouds coalesce and grow so that they become heavy enough to fall as rain in the ITCZ? Mini-Zombie Break ! DANCE YOUR PH.D! “Precipitation Initiation in Warm Clouds” This dances shows how a rain drop can form when one SLIGHTLY LARGER RAIN DROP is present among a population of smaller drops. In the tropics, really large drops (heavy enough to fall as rain ) only form after mixing occurs. Men are Condensation nuclei Women are H2O droplets In the “mixing process” the H2O droplets connect with “condensation nuclei partners” . . . but eventually some H2O’s abandon their original nuclei for a larger one! Through “coalescence” a single nucleus attracts all the other water droplets ! When the H2O droplet grows large enough . . . . . . RAIN FALLS! http://www.youtube.com/watch?v=4O7G7F_e7I0 The opposite of rain = subsidence (sinking air) In HIGH PRESSURE ares! HIGH PRESSURE AREAS: Forced sinking (e.g. in HADLEY CELL) leads to “compaction” and warming of the sinking air Air warms increase in the water vapor holding capacity clear skies, dry air and ARID REGIONS / DESERTS! In general: Winds tend to flow from HIGH LOW Pressure areas Subtropical HIGH PRESSURE H H L L H H Intertropical Convergence ITCZ Subtropical HIGH PRESSURE p 64 BUT -Hadley cell circulation does not reach high latitudes! HADLEY CELLS = key drivers! BUT – Hadley cell circulation does not reach high latitudes! Convection cell transfer of thermal energy from low latitude area of energy SURPLUS to higher latitude area of energy DEFICIT p 64 Why Hadley convective cell transport breaks down at higher latitudes: 64 UPPER LEVEL CIRCUMPOLAR WINDS ! “Wave” transport of thermal energy instead of Hadley cell transport! p 65 Hadley Cells are only efficient in transporting energy to the mid-latitudes Hadley Cells + Rossby Waves together are needed! Energy is transported from areas of surplus to deficit in form of: (sensible heat) & (latent energy) IN TWO MAIN WAYS: Atmospheric circulation moves warm & cold air north & south across latitudes H2O condenses in high latitudes LE H H2O is evaporated in low latitudes H LE p 65 The Community Climate System Model (CCSM) is a coupled climate model for simulating Earth's climate system. It simulates the earth's atmosphere, ocean, land surface and sea-ice water vapor = WHITE precipitation rate = ORANGE. http://www.vets.ucar.edu/vg/T341/index.shtml Net radiation deficit Net radiation surplus (at top of atmosphere) Net radiation deficit p 64 THERMAL ENERGY IS TRANSPORTED FROM LOW TO HIGH LATITUDES TO BALANCE OUT THE DEFICIT! p 64 BUT WHAT ABOUT G ? G is a STORAGE component, not a transfer component BUT energy stored in the OCEAN, can later be transported via ocean currents as H ! WARM & COLD SURFACE OCEAN CURRENTS: 97 p P66 Large OCEAN GYRES -- driven by Trade Winds & Westerlies in Oceanic Subtropical HIGH PRESSURE CELLS (STH) Leads to SURFACE ocean currents H H H H H H 97 pP66 Energy is transported from areas of surplus to deficit via: H (sensible heat) & LE (Latent Energy) p 65 Both ATMOSPHERE & OCEAN play important roles in BALANCING OUT ENERGY SURPLUS & DEFICIT AREAS: ATMOSPHERE more important in mid high latitudes OCEAN transports MOST of the energy in LOW subtropical latitudes Poleward transport of energy in N.H. P 67 ZOMBIE BREAK ! Turn to Page 30 in Class Notes . . . . As you watch the segments of this film . . . . Check off the changes on p 30 in CLASS NOTES : Checklist of Direct Observations of Recent Climate Change: etc., etc. p 30 Watch the video carefully – at some point a feedback loop process is described. Can you recognize it ??? (HINT: it is one of the loops shown on p 56 in Class Notes) Make a note of it . . . . . AFTER THE FILM: GROUP BONUS POINT CHALLENGE - PART 1: State which feedback loop was described in the film and sketch the FEEDBACK DIAGRAM for it on one side of the INDEX CARD provided. GROUP BONUS POINT CHALLENGE - PART 2: NOW – on the back of the index card, as a group, complete the feedback loop on the bottom of page 58 by linking the components with the proper coupling arrow symbols as used in the SGC text p 58 albedo Extent of ice cover Amount of melting SW radiation absorbed Ocean temperature The ANSWER! + albedo Extent of ice cover - Amount of melting + - - SW radiation absorbed + + Ocean temperature SNOW AND ICE ALBEDO Feedback BE SURE TO REVIEW THE CLASS FOLLOW-UP IF YOU WANT TO GO OVER THESE ANSWERS AGAIN . . . . . See you on Thursday – don’t forget RQ-6!