Presentation on theme: "Atmospheric CO 2 & Temperature – what is normal? what is normal? Presented by Julie Brigham-Grette and Beth Caissie Julie Brigham-Grette and Beth Caissie."— Presentation transcript:
Atmospheric CO 2 & Temperature – what is normal? what is normal? Presented by Julie Brigham-Grette and Beth Caissie Julie Brigham-Grette and Beth Caissie July 2010
CO 2 and TemperatureWhat is Normal? Concepts to Address before you begin –Climate vs. Weather –Greenhouse Gasses –The Carbon Cycle Play the game? Photosynthesis and Decomposition Concepts to grasp During the Activity –How much of a change in CO 2 concentration and other GHGs is natural? –What is the normal range of CO 2 and temperature variability? How is normal defined in this context? –What is the relationship between CO 2 and global temperatures?
What causes this change in annual Carbon dioxide?
Seasonal changes cause up/downs in CO 2 in the atmosphere Especially driven by Northern Hemisphere. Spring - photosynthesis drops CO 2, Fall - decomposition causes increase in CO 2 http://www.esrl.noaa.gov/gmd/ccgg/trends/
Monitoring of CO 2 and other Greenhouse gases around the world All get similar measurements Why?
Drilling in Greenland http://passporttoknowledge.com/polar- palooza/pp09a.php Video podcast from Polar Palooza
Summit Station, Greenland photo by Michael Morrison, GISP2 SMO, University of New Hampshire; NOAA Paleoslide SetCore: Eric Cravens, Assistant Curator, U.S. National Ice Core Laboratory; Matt Nolan, UAF Fossil air! Trapped in the ice; records past atmosphere
Raynaud, 1992Gases within bubbles = fossil atmospheric air
Firn-ice transition Depth of transition depends on surface temperature and accumulation rate Camp Century, Greenland: 68 m below ice sheet surface Vostok, Antarctica: 100 m below ice sheet surface Low precip. and cold = long time to make ice High precip. and warm = short time to make ice
Classroom options: Plot by hand on graph paper, Plot on computer using Excel Overlay Temperature on CO 2 Instructions for Excel on website Analysis: Defining amplitude, frequency, periodicity Defining Normal? Understanding the relationship between Greenhouse gases and temperature.
Oxygen (8 protons) 16 O 17 O 18 O 99.8% 0.04% 0.2% Hydrogen (1 proton) 1 H 2 H ( Deuterium ) 3 H ( tritium ) 99.98% 0.016% (bombs) So, can make 9 isotopic combinations of H 2 O, e.g., 18 ( 1 H 2 16 O) to 22 ( 2 H 2 18 O) light water heavy water In paleoclimate studies… 1 H 1 H 16 O to 1 H 2 18 O
General Equation: 18 O = 18 O/ 16 O sample - 18 O/ 16 O standard x 1000 18 O/ 16 O standard Expressed in per mille ( 0 / 00 ) Negative values = lower ratios = isotopically lighter (less 18 O than 16 O) Positive values = higher ratios = isotopically heavier (more 18 O than 16 O)
Ice Sheet ocea n 0 -10 -20 -30 -40 -50 18 O isotopic depletion In Sea In Ice Glacials = enriched 18 O depleted 18 O Interglacials = depleted 18 O enriched 18 O Evaporation of more 16 O
Ice Sheet ocean D isotopic depletion depends on temp of source area, Distance and processes during precipitation Isotopic ratios are used to model temperature, at Vostok; empirically this is roughly: Temperature (deg-C) = -55.5 + (δD + 440) / 6 http://eesc.columbia.edu/courses/ees/climate/labs/vostok/ See also http://www.globalchange.umich.edu/gctext/Inquiries/Inquiries by _ Unit/Unit _ 8a.htm
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