Atmospheric Basics AOSC 200 Tim Canty Class Web Site: http://www.atmos.umd.edu/~tcanty/aosc200 Topics for today: Structure of the Atmosphere Temperature vs height Atmospheric pressure Atmospheric composition CO 2 Lecture 02 Aug 31 2017 1 Today s Weather Map http://www.wpc.ncep.noaa.gov/sfc/namussfcwbg.gif 2
Today s Forecast http://www.hpc.ncep.noaa.gov/national_forecast/natfcst.php 3 Evidence for a Changing Climate Global Monthly Temperature 4
Weather and Climate 1 C (1.8 F) rise in temperature..so what? What if temperatures COOLED by 1-2 C? This actually happened from ~1400 1800AD, known as the Little Ice Age Winter landscape with iceskaters, Avercamp 5 Weather and Climate 1 C (1.8 F) rise in temperature..so what? What if temperatures COOLED by 5 C? This actually happened about 18000 year ago, known as the last Ice Age 6
Understanding the Atmosphere Weather and climate are easy to talk about. Do a google search on the words climate change and see how many hits you get. As scientists, we need to understand fundamentally what affects both weather and climate and how the two can interact. This means we re going to have to dig into some details. 7 Atmospheric temperature Fig 1.9: Essentials of Meteorology a 8
Atmospheric temperature Troposphere: Temperature decreases with height Fig 1.9: Essentials of Meteorology Copyright 2017 University i of Maryland 9 Atmospheric temperature Tropopause: there s a pause in the temperature decrease Fig 1.9: Essentials of Meteorology Copyright 2017 University i of Maryland 10
Atmospheric temperature When temperature increases with increasing height it s called a Temperature Inversion Stratosphere: Temperature increases with height Fig 1.9: Essentials of Meteorology Copyright 2017 University i of Maryland 11 Atmospheric temperature Stratopause: there s a pause in the temperature increase Fig 1.9: Essentials of Meteorology Copyright 2017 University i of Maryland 12
Atmospheric temperature Mesosphere: Temperature decreases with height Fig 1.9: Essentials of Meteorology Copyright 2017 University i of Maryland 13 Atmospheric temperature Mesopause: there s a pause in the temperature decrease Fig 1.9: Essentials of Meteorology Copyright 2017 University i of Maryland 14
Atmospheric temperature Thermosphere: Temperature increases with height Fig 1.9: Essentials of Meteorology Copyright 2017 University i of Maryland 15 Understanding Pressure Fig 1.7: Essentials of Meteorology 16
Understanding Pressure Copyright 2017 University it of Maryland Fig 1.8: Essentials of Meteorology 17 Understanding Pressure Ideal Gas Law pressure volume = constant temperature or pressure = density temperature constant
Atmospheric Composition (What are you breathing?) Table 1.1: Essentials of Meteorology 19 Carbon Dioxide (CO 2 ) Cycle One of the most talked about Greenhouse Gases. Some CO 2 is produced naturally Some CO 2 produced by human activity (anthropogenic) Once in the air, some CO 2 : stays there goes into ocean goes into land CO 2 stays in the air for ~200yrs Fig 1.3: Essentials of Meteorology 20
Carbon Dioxide (CO 2 ) Measured at Hawaii Measurements made from Mauna Loa, Hawaii http://keelingcurve.ucsd.edu/ 21 Carbon Dioxide (CO 2 ) Amount of CO 2 relative to today Today Berner, Science, 276, 544, 1997 22
NASA Orbiting Carbon Observatory (2) Launched July 2, 2014 23 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/oceanacidification-from-domestic-to-international/ 24
Carbon Dioxide (CO 2 ) Cycle Currently, there are more sources than sinks. As a consequence, CO 2 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 CO 2 https://directory.eoportal.org/web/eoportal/satell ite-missions/o/oco-2 25 Methane (CH 4 ) Actual data much noisier than what is shown in textbooks http://www.esrl.noaa.gov/gmd/dv/iadv/graph.php?code=mlo&program=ccgg&type=ts 26
Methane Sources and Sinks http://www.giss.nasa.gov/research/features/200409_methane/ 27 Methane Sources and Sinks Methane is mainly lost by chemical reactions in the atmosphere The carbon in methane eventually becomes CO 2 http://www.giss.nasa.gov/research/features/200409_methane/ 28
Aerosols (really tiny!!!!) Fig 1-10 Meteorology: Understanding the Atmosphere 29 Aerosols (really tiny particles!!!!) Aerosols help form rain and snow Main sources: oceans (sea salt), erosion, fires, volcanoes, and human activity Can be harmful to human health Fig 1-10 Meteorology: Understanding the Atmosphere 30
Aerosol Observations Ship Tracks! Fig 1.6: Essentials of Meteorology 31 Aerosol Observations Satellite Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) April 17, 2010, CALIPSO captured this image of the Eyjafjallajökull ash cloud. http://eosweb.larc.nasa.gov/prodocs/calipso/featured_imagery/iceland_volcano_ash_cloud.html 32
Aerosol Modeling http://climate.nasa.gov/news/2218/ 33 Ozone Absorbs UV radiation Smog!!! http://www.aoas.org/article.php?story=20080522125225466 34