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Composition and Energy AOSC 200
Tim Canty
Class Web Site: http://www.atmos.umd.edu/~tcanty/aosc200
Lecture 03Sept 5 2017
Topics for today:
•Atmospheric composition cont.• Energy transfer
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Today’s Weather Map
http://www.wpc.ncep.noaa.gov/sfc/namussfcwbg.gif
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Today’s Forecast
http://www.wpc.ncep.noaa.gov/national_forecast/natfcst.php
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NASA Orbiting Carbon Observatory (2)
Launched July 2, 2014
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NASA Orbiting Carbon Observatory (2)
https://oco.jpl.nasa.gov/
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Recent Science
http://www.pmel.noaa.gov/co2/story/Ocean+Acidification
“There has been a 30% increase in the acidity of the ocean since 1700, and we now expect that by 2100, it will have become a 100% increase. This constitutes a rate of change in ocean chemistry that is 10 times anything scientists can document over the last 50 million years.”
http://newswatch.nationalgeographic.com/2014/09/02/ocean-acidification-from-domestic-to-international/
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Carbon Dioxide (CO2) Cycle
Currently, there are more sources than sinks.
As a consequence, CO2 in the air is rising.
This rise is correlated with the rise in temperatures…
… but more on that in future lectures
Currently, few ways to reduce CO2
https://directory.eoportal.org/web/eoportal/satellite-missions/o/oco-2
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http://www.esrl.noaa.gov/gmd/dv/iadv/graph.php?code=MLO&program=ccgg&type=ts
Actual data much “noisier” than what is shown in textbooks
Methane (CH4)
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Methane Sources and Sinks
http://www.giss.nasa.gov/research/features/200409_methane/
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Methane Sources and Sinks
http://www.giss.nasa.gov/research/features/200409_methane/
Methane is mainly lost by chemical reactions in the atmosphere
The carbon in methane eventually becomes CO2
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Aerosols (really tiny!!!!)
Fig 1-10 Meteorology: Understanding the Atmosphere
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Aerosol Observations
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Ship Tracks!SSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSShhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhiiiiiiiiiiiiiiiiiiiiiiippppppppppppppppppppppppppppppppppppppppppppppppp TTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTrrrrrrrrrrrrrrrrraaaaaaaaaaaaaaaaaaaaaacccccccccccccccccccckkkkkkkkkkkkksssssssssssssss!!!!!!!!
Fig 1.6: Essentials of Meteorology
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Aerosol Observations – Satellite
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Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO)
http://eosweb.larc.nasa.gov/PRODOCS/calipso/featured_imagery/iceland_volcano_ash_cloud.html
April 17, 2010, CALIPSOcaptured this image ofthe Eyjafjallajökull ashcloud.
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Ozone
14http://www.aoas.org/article.php?story=20080522125225466
Ozone in the stratosphere absorbs UV radiation. This is good!!!
Ozone at the surface (a.k.a. Smog!) is a pollutant. This is bad!!!
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Temperature Scales
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Fig 2.2: Essentials of Meteorology
Celsius (centigrade): melting point of water is 0°C and the boiling point is 100°C.
Fahrenheit: melting point of water is 32°F and the boiling point is 212°F.
Kelvin: similar to Celsius but the coldest temperature is 0K. (Kelvin scale never goes negative)
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Energy Transfer
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Fig 2.3: Essentials of Meteorology
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Latent Heat
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Latent heat: the heat required to melt or evaporate a substance
Ice in the cooler absorbs heat from the drinks
Result: the ice melts while the drinks stay cold
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Latent Heat
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Latent heat: the heat required to melt or evaporate a substance or the heat given off when something condenses or freezes
When water freezes or condenses, the latent heat is released back into the environment
Fig 2.4: Essentials of Meteorology
As water condenses to form a cloud, all of the heat that went into evaporating the water is released to the air.
Clouds warm the air inside the cloud.
Amount of energy released equivalent to a small nuke
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Specific Heat
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The specific heat of a substance is the amount of heat required to increase the temperature of 1 gram of the substance 1° C
Table 2-1 Meteorology: Understanding the Atmosphere
Water takes longer to heat (and longer to cool) than dirt
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Energy Transfer: Conduction
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• Conduction – requires contact, energy transferred from molecule to molecule
• Air is not a good conductor
• Metals are excellent conductors
• Very important at Earth’s surface
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Energy Transfer: Convection
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• Convection – energy transferred by movement of fluids (in science, air is considered a fluid)
• Surface energy transferred upward by convection
• “Hot air rises and cool air sinks”
• Lava lamps are a good example of convection
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Energy Transfer: Convection
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Fig 2.6: Essentials of Meteorology
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Temperature and Density
http://www.our-planet-earth.net/learning/3c.html
As temperature rises and the parcel expands the air inside the parcel gets less dense
(all of the air molecules are spread out over a larger volume)
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Temperature and Density
http://www.our-planet-earth.net/learning/3c.html
Surrounding air is denser and heavier and sinks
The less dense air is pushed up by the sinking, heavy air. “The less dense air floats” or
“Hot air rises, cold air sinks”
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Energy Transfer: Convection
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Fig 2.7: Essentials of Meteorology
Rising, hot air creates a convective circulation cell called a thermal
Thermals will eventually spread out, sink and move back to the starting point creating wind
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Energy Transfer: Advection
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Advection – horizontal movement of air (a.k.a. wind)
Fig 2-4 Meteorology: Understanding the Atmosphere
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Rising and Sinking Air
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Fig 2.U1: Essentials of Meteorology
Air that is pushed upward will expand and cool down Air that sinks will contract and heat up
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Energy Transfer
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Radiative Heat – heating due to electromagnetic radiation
called radiation but is different from nuclear radiation
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Electromagnetic Spectrum
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Spectrum: range of valuesWavelength: length of one wave ( , lambda)
Fig 2.8: Essentials of Meteorology
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Electromagnetic Spectrum
Fig 2-7 Meteorology: Understanding the Atmosphere
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The energy from the Sun peaks at 0.5 m (the visible portion of the spectrum)
Fig 2.9: Essentials of Meteorology
Solar Spectrum
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Not all radiation makes it to the surface (this is a good thing!)http://imagine.gsfc.nasa.gov/Images/science/EM_spectrum_atmosphere.jpg
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The energy from the Sun peaks at 0.5 m (the visible portion of the spectrum)The energy from the Earth peaks at 10 m (in the infrared portion)
Fig 2.10: Essentials of Meteorology
Solar Spectrum