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Thursday Nov 4 th

Thursday Nov 4 th SIT WITH YOUR GROUP TODAY! Wrap up of Topic #13 Natural Climatic Forcing (Volcanoes) then Introduction to TOPIC #14 GLOBAL WARMING & ANTHROPOGENIC FORCING.

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Thursday Nov 4 th

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  1. Thursday Nov 4th SIT WITH YOUR GROUP TODAY! Wrap up of Topic #13 Natural Climatic Forcing (Volcanoes) then Introduction to TOPIC #14 GLOBAL WARMING & ANTHROPOGENIC FORCING ANNOUNCEMENT: The due date for RQ-7 is NEXT TUESDAY, Nov 9thIt will be posted tomorrow. Don’t FORGET!!!NOTE: your last 3 RQ’s will all be due on TUESDAYS instead of Thursdays

  2. Where are we now ?

  3. SEMESTER WRAP-UP: 3 RQ’s (20 pts), Test #4 (25 pts), + Final Exam ( 100 pts)+ clicker pts (10 individual 5 group) TOTAL OF 215 PTS LEFT !! To be posted this weekend Today! 30 pts 5 pts 20 pts Due last week of classes

  4. CLICKER QUESTION: Q1 In the film shown in class on TUESDAY, what was Willie Nelson promoting?? A – Solar power B – Corn ethanol C – Biodiesel D – Hybrid trucks

  5. Wrap up of TOPIC # 13 NATURAL CLIMATIC FORCING: • Volcanic Eruptions • (pp 71-74)

  6. How the Climatic Effect Occurs . . . . through the ENERGY BALANCEof course! p 71

  7. Mt Merapi Latitude: 7°32'30"S “Indonesia's Mount Merapi erupted with renewed strength on Wednesday, the fourth eruption in eight days, forcing authorities to move refugee shelters further away from the volcano, a vulcanology official said. The volcano, near Yogyakarta on Java island, spewed clouds of ash and gas 5 km (3 miles) into the sky for more than an hour on Wednesday, its biggest eruption so far in the past 10 days.

  8. How CLIMATICALLY EFFECTIVE will this eruption be?? Q2 - Will it get into the stratosphere? 1 – YES 2 - NO, Probably not Hint: See p 39

  9. WHICH ERUPTIONS ARE THE MOST CLIMATICALLY EFFECTIVE? •  EXPLOSIVE • high SULFUR content in magma • whose eruption clouds inject into the STRATOSPHERE • Low Latitude Eruptions p 72

  10. Q3 Why do you think Low Latitude eruptions are more climatically effective and have more of a effect? • Because the temperature is warmer in tropical latitudes and hot air rises. • Because the Hadley Cell circulation can distribute the volcanic aerosols into both hemispheres if the eruption occurs near the equator. • Because the tropopause is lower over Low Latitudes and hence its easier for aerosols to get injected into the stratosphere where they will not be rained out. 0 / 150

  11. Q3 Why do you think Low Latitude eruptions are more climatically effective and have more of a effect? • Because the temperature is warmer in tropical latitudes and hot air rises. • Because the Hadley Cell circulation can distribute the volcanic aerosols into both hemispheres if the eruption occurs near the equator. • Because the tropopause is lower over Low Latitudes and hence its easier for aerosols to get injected into the stratosphere where they will not be rained out. 0 / 150

  12. The GEOGRAPHIC LOCATION of the erupting volcano influences the climatic effectiveness of an eruption because of the General Circulation of the Atmosphere. • Low latitude eruption clouds get circulated more broadly & in both hemispheres p 72

  13. HOW DO REGIONAL CLIMATES RESPOND TO AN EXPLOSIVE ERUPTION? In general, explosive eruptions warm the stratosphere and cool the troposphere, especially during the summer season. p 72

  14. Major tropical eruption: • Stratospheric heating is larger in the tropics  enhanced pole-to-equator temperature gradient, esp. in winter. • N.H. winter  enhanced gradient produces a stronger polar vortex  stationary wave pattern of tropospheric circulation resulting in winter warming of NH continents. p 72

  15. HOW MUCH TROPOSPHERIC COOLING CAN OCCUR AND HOW LONG DOES IT LAST? ·Individual large eruptions can result in a 1-to-3 year cooling of average surface temperatures of 0.3 to 0.7º C. Tambora in 1815Krakatau in 1883Agung in 1963El Chichon in 1982 p 72

  16. HOW IMPORTANT IS EXPLOSIVE VOLCANISM AS A FORCING MECHANISM FOR PAST AND FUTURE CLIMATE CHANGES? ·interdecadal climate change (“Little Ice Age”) · Individual years, such as 1816, the “Year without a Summer” after the eruption of Tambora in 1815 · Link not always conclusive – e.g., El Nino at same time, etc. p 72

  17. p 72

  18. Typical Global Cooling Pattern after a Volcanic Eruption Average changes in temperature (based on 5 major eruptions) COOLING  Years before eruption Years after eruption  This graph shows the global mean temperature changes for years before (-) and after a large eruption (at year zero) p 72

  19. Comparison Table of Eruptions Estimated N.H. temperature change °C Latitude How muchaerosol got into each hemisphere How much magma  how big an eruption Sulfur-rich if high H2SO4 p 73

  20. G-4 ACTIVITY ON VOLCANISM & CLIMATE P.S. This is one of my favorite questions to ask on the FINAL EXAM!!!!

  21. #1. List 4 reasons why Tambora in 1815 resulted in the largest GLOBAL cooling: # 2. Give at least two reasons why the eruption of Mt St. Helens was NOT a very climatically effective eruption:

  22. Write in the ERUPTIONS at top of page #3. Which levels show a COOLING and which show a WARMING immediately after the eruption? Agung (1963) Pinatubo (1991) Pinatubo Agung ** NOTE: At the time of the El Chichon eruption, there was warming taking place due to a strong El Nino, hence the temperature change after this eruption shows a different response. When ANSWERING # 3 & #4 – focus on Agung & Pinatubo only El Chichon ** Pinatubo Agung El Chichon ** p 74

  23. Write in the ERUPTIONS at top of page #4. Explain WHYeach level’s TEMPERATURE responded as it did to theAgung & Pinatubo eruptions? (by referring to the Radiation Balance) Agung (1963) Pinatubo (1991) C Agung Pinatubo El Chichon ** When ANSWERING # 3 & #4 – focus on Agung & Pinatubo only p 74

  24. Net radiation deficit Net radiation deficit What do the black & gray areas represent? (at top of atmosphere) REMEMBER THIS IMPORTANT GRAPH? Net radiation surplus

  25. SKETCH A NEW CURVE A OR NEW CURVE B to show how the energy balance would change if a major volcanic eruption occurred . p 74

  26. SKETCH A NEW CURVE A OR NEW CURVE B to show how the energy balance would change if a major volcanic eruption occurred . CURVE ACURVE B is B A Curve A orCurve B can move Up or Down due to a radiative forcing in SW or LW

  27. Smaller Surplus A moves down LargerDeficit Larger Deficit If incoming energy represented by Curve A is reduced (A curve goes down)

  28. LargerSurplus Smaller Deficit Smaller Deficit B moves down If outgoing energy represented by Curve B is reduced (B curve goes down)

  29. LargerSurplus Smaller Deficit Smaller Deficit A moves up If incoming energy represented by Curve A is increased (A curve goes up)

  30. SmallerSurplus LargerDeficit B moves up Larger Deficit If outgoing energy represented by Curve B is increased (B curve goes up)

  31. Assume: • that the eruption produces a long-lived aerosol veil in the stratosphere over both hemispheres • that this veil reflects large amounts of incoming solar radiation back to space before it enters the troposphere’s earth-atmosphere system shown in the graph. • Hint: you do not need to worry about stratospheric warming for this question. p 74

  32. IF CURVE A If CURVE B is affected: is affected: Four scenario’s are possible for how you should sketch the new graph

  33. THE ANSWERS!

  34. #1. List 4 reasons why Tambora in 1815 resulted in the largest GLOBAL cooling: #1 Low latitude eruption  both hemispheres #2 Large amount of eruptive material (50 sq km!) #3 Aerosol cloud was HUGE and went into both hemispheres equally #4 Sulfuric acid (H2SO4) content was very large p 74

  35. #2. Give at least two reasons why the eruption of Mt St. Helens was NOT a very climatically effective eruption: #1 High latitude – could only affect part of Northern Hemisphere #2 Low sulfur content (also, low volume, didn’t get to S. Hemisphere, etc.) p 74

  36. # 3 HOW did the temperature at the 4 levels respond to the Agung and Pinatubo eruptions? #4 EXPLAIN WHY – referring to Radiation Balance? Level A (Surface) – CooledWhy? by sulfate aerosols in stratosphere and therefore less SW got into troposphere to be absorbed by Earth’s surface Level B (Lower Troposphere) – Cooled Why? by stratospheric aerosols => less SW absorbed at surface and in troposphere, ALSO: less radiated up into troposphere from the cooler Earth’s surface p 74

  37. Level C (Lower Stratosphere) – Warmed immediately after both eruptionsWhy? Sulfate aerosols in the stratosphereabsorbedsome wavelengths of incoming SW and heated up, they also absorbed some of the Earth’s outgoing LW as it radiated up out of the troposphere p 74

  38. TO SUMMARIZE: 2 KEY POINTS • Major eruptions with a long-lived sulfate aerosol veil REFLECT incoming solar radiation back to space BEFORE it enters the mid- & lower troposphere or gets to the Earth’s surface, hence the troposphere & surface get COOLER after an eruption. • The aerosols in the stratosphere can also ABSORB some wavelengths of incoming SW and outgoing LW, so that the stratosphere WARMS slightly after an eruption.

  39. Show how the energy balance would change if a major volcanic eruption occurred: WHICH ONE IS RIGHT ? Does the change affect CURVE A or CURVE B?

  40. A moves down, and B stays the same . . . . . . . but eventually B will also move down a bit due to cooler Earth temps and less outgoing LW p 74

  41. ZOMBIE BREAK !

  42. MOVIETIME!!

  43. TOPIC # 14GLOBAL WARMING & ANTHROPOGENICFORCING • TODAY’s 3 KEY CONCEPTS:Carbon / Forests / DeforestationComputer Model Evidence for Anthropogenic GW ForcingTying it all together w/ RADIATIVE FORCING GRAPHS

  44. TOPIC # 14GLOBAL WARMING & ANTHROPOGENICFORCING Part A - CARBON RESERVOIRS & FLUXES: Natural vs. Anthropogenically Enhanced (or How does all that “C” get into the atmosphere??) Class Notes pp 75

  45. “I'm extremely concerned that the Earth has a chronic disease, and that chronic disease is CO2 syndrome, it‘s something that's creeping on us. We have plenty of fossil fuel so it's going to continue to get worse, and it's going to affect every aspect of life on the planet, from food production to drinking water to coastlines to the plight of the poor in the tropics, and so forth.” ~Wally Broecker , Paleoclimatologist p 75

  46. CO2 & CARBON RESERVOIRS CO2 in the atmosphere is one place CARBON resides in the Earth-Atmosphere system. Where else is carbon located and how does it move (flux) from one reservoir to another? 

  47. Major Reservoirs of Carbon at or near the Earth’s surface Gt (C) = gigaton carbon p 75

  48. Amount of carbon is expressed in units of Gtons (gigatons) of carbon: GT(C) • Amounts represent the MASS OF CARBON ATOMS ONLY, not other atoms to which C is attached (e.g. CO2) p 75

  49. 2740 Empire State Buildings or 77 Empire State Buildings made out of solid lead  • 142,857,142 African elephants -- That’s enough elephants stacked on top of each other to reach from Earth to the moon and halfway back   • Greater than the mass of all the humans on the planet  One gigaton is . . .  

  50. Major Reservoirs of Carbon at or near the Earth’s surface Gt (C) = gigaton carbon p 75

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