Earth s equatorial radius is 6378 km and the atmosphere is 500 km.

Transcription

1 The Atmosphere is a Structure very and thin shield that circulation protects us. Importance for climate Composition and significance Atmospheric deposition Earth s equatorial radius is 6378 km and the atmosphere is 500 km. 1

2 Wind, rain and radioactivity do not stop at the border for passport control, but go where they will. Pollution? Coming soon to a place near you. We re all down winders now. David Nyhan Boston Globe Prinn 4.01 Chemically complex dynamic system interacting in significant ways with the oceans, land, and living organisms. 2

3 Effect of atmospheric constituents on biogeochemical cycles influenced by Residence time Reactivity Water solubility Important terms Pollutant any substance, as certain chemicals or waste products, that renders the air, soil, water, or other natural resource harmful or unsuitable for a specific purpose. Contaminant-added and changes from original concentration Is CO2 a pollutant or contaminant? Nutrient-A substance that provides nourishment essential for growth and the maintenance of life, i.e. trace metals Se, Zn Source-Receptor Primary versus Secondary Pollutant CO2, CO, VOCs, N2O,NO, NH3, SO2, H2S NO2, HNO3, O3, aerosols 3

4 troposphere where weather occurs contains 95% of Earth's mass Heated from beneath; decreasing temperature with altitude; unstable, causes mixing Consists of 20% O 2, 79% N 2, 0.03% CO 2, 1% Ar, H 2 O Fig Brooks/Cole Publishing Company / ITP Stull

5 Stull 1998 Figure 3.2 Schlesinger (1997) and S and B 5

6 Factors driving atmospheric circulation Incoming solar radiation Rotation of the earth High and low pressure systems Need to fill in air once air has moved from one place to another Intersection with land masses Atmosphere transports heat, water and atmospheric constituents 60 N Easterlies (from the east) Westerlies (from the west) 30 N Northeast tradewinds (Doldrums) equator Southeast tradewinds 30 S Westerlies 60 S Easterlies Initial pattern of air circulation Deflections in the paths of air flow near the earth s surface 6

7 Stull 1998 Fig 2.6 Ruddiman 7

8 Figure B4. the simplified global pattern becomes more complicated when continents added into the picture. NRC 8

9 Important areas of transport ITCZ confluence of NE (N Hemisphere) and SE trade winds Jet streams.. Subtropical and polar jet streams- Atmospheric Rivers Imagine a stream of water thousands of km long and as wide as the distance between NY and DC flowing towards you at 30 mph Mississippi Rivers..a river of water vapor in the atmosphere EOS 92 #32 9

10 1-4 wks 3-13 d 1-2 wk 1y 1-2 m 1-2 wk 4-17 d Schematic of some major atmospheric transport pathways (focusing on those affecting North America). Micrometeorological scale 0 to10 km Mesometeorological scale 10 to 100s km Synoptic scale- 100 to 1000s km General Circulation Global scale->5 x 10^3 Primary versus secondary S and B Table 3.1 and Table

11 Schlesinger Fig 3.5 Concentrations stable for those that are inert with increasing variability for those of low concentration and chemically reactive Schlesinger (1997) S and B Table 3.5 Source strength source variability-sink strength and variability Anaerobic decay Fires, decay of chlorophyll Vegetation emissions C- soot/co2 inert-sink photosynthesis/ocean Table 3.4 biogenic gases Denitrification Fossil fuels Agriculture Plankton Decaying proteins Biological activity Fossil fuels Sinks are oxidation, gas exchange, washout 11

12 Oxidative capacity of the atmosphere Cleanses the atmosphere Did not start until oxygenated atmosphere O 3 attack water and makes OH NO important also Not constant- light, water vapor, atm chemistry Impacts Removes CH 4 and CO Starting point for aerosols What is Ozone? Gaseous ozone (O 3 ) is an allotrope of oxygen. It is a natural component of Earth s atmosphere, existing mainly in the upper atmosphere (stratosphere). It is formed from O 2 via a variety of photochemical reactions. Ozone is unstable and will react with (oxidize) surfaces, vegetation and many other materials, including our lungs. Interesting note- Some early work on ozone focused on damage to aircraft seals and rubber at high elevation. The reaction with rubber bands was also used as a means to quantify the amount of ozone in the atmosphere. 12

13 Formation in the Troposphere Ozone Table 3.6 S and B Troposphere- Natural and anthropogenic Preindustrial ppb stratosphere intrusions, lightning, natural surface emissions of CO, CH4 and VOCs, wildfire Current baseline ppb Forms OH influences oxidizing capacity of the atmosphere Stratosphere Natural processes and anthropogenic impacts 13

14 CO2 is not reactive with other gases in the atmosphere Concentration is affected by interaction with Earth s surface Carbonate-silicate cycle Gas exchange with sea water following Henry s Law Photosynthesis and respiration Reactions some are in S and B starting pg 66 From the stratosphere and natural source of VOC and NO O 3 O 3 + H2O 2OH OH + CO CO 2 + H (H+O 2 HO 2 ) OH + CH 4 CH 3 + H 2 O 14

15 nitrogen NO and NO2=NOx Combustion Natural sources-wildfires, lightning, microbial processes NO in combustion converted to NO2 NO2 + light NO + O O + O2 O3 Importance as a sink 15

16 Hydrocarbons + nitrogen oxides + light > ozone and other oxidants Stamenkovik et al Atmos. Environ. 41,

17 NO 2 Concentrations and NOx emissions in Southern California NOx emissions in Southern California now less than half of what they were 20 years ago! (Lurmann et al 2015) Changing O 3 at Europe mountain sites Pre-industrial background O 3 Volz et al 1988; Marenco et al

18 Changing background and AQ standards Ozone Time For trends in background O 3 see: Gratz et al 2014; Jaffe et al 2003; Parrish et al 2004; Oltmans et al 2006; Jaffe and Ray 2007; Cooper et al 2010; 2014; NAS 2010; Papers in Special Section of STOTEN on NVROI O 3 distributions across the Western US and gaps in data 3-year Average 4 th Highest 8-Hour Ozone value by County AQS Federal Reference Method data from the monitoring site in each County with the highest Ozone values 18

19 Major Air Pollutants 150 ug/m3 12-annual h ug/m3 9 ppm 8hr ppm 8hr Lead 0.15 ug/m3 The Nevada Rural Ozone Initiative (NVROI) Great Basin National Park MDA8 Ozone: 1993 to 2013 What are the spatial and temporal patterns in O 3 across rural Nevada? What sources contribute to the observed O 3 in Nevada? 19

20 Nevada Rural Ozone Initiative Hypothesis Given Limited Sources Complex Terrain Location Climate Entrainment of air aloft will influence measured O 3 and thus, regional and global sources with contribute to O 3 measured in rural Nevada. Funded by the Nevada Division of Environmental Protection Fine et al., 2015 Great Basin National Park Fine et al.,

21 Rural Monitoring Sites White River Valley (El. 17 Railroad Valley (El. 143 Warm Springs Summit(El. 2 The State of Nevada is -uniquely poised to monitor air transported over the Pacific Ocean and being delivered to the United States Mean elevation 1676 m S I E R R A NEVADA (Gustin et al., 2015) 200 mountain ranges Map source: 21

22 Limited ozone precursor emission sources in NV 2011 Nation Emission Inventory for Facilities in Nevada and surrounding states VanCuren et al., in preparation VanCuren and Gustin, 2015 Relatively high baseline ozone Continuous impacts at high elevation sites Intermittent at low elevation sites Shallow nocturnal boundary layer in valleys O 3 delivered to valleys during the day consumed by surfaces at night Gustin et al., 22

23 Correlation between sites in NV and high elevation in California Monthly means above those considered chronic threshold levels for trees (Gustin et al., 2015; Fine et al., 2015) Change higher in the Valleys Rapid increase in ozone ~8-10:00 Convective growth of the boundary layer Mixing of air aloft : bottom up entrainment of pollution in the residual layer/free troposphere Secondary peak in rate of increase ~13:00 Photochemical production from local sources or in put from regional transport Rapid decrease in ozone at dusk due to reaction with surfaces. Gustin et al.,

24 Seasonal patterns Gustin et al., MDA 8 higher in the spring (LRT) Summer(Wildfires) -Need to consider climate change and O 3 importance as a greenhouse gas -Public lands and National Parks in Western United States impacted (also wildlife and humans) Unraveling the Sources of Ground Level Ozone in the Intermountain Western United States Using Pb Isotopes Use of lead isotopes to source apportion ozone sources This figure from Christensen et al. Science of the Total Environment, 2015 Please also see VanCuren and Gustin, 2015 Also look at 24

25 Mercury loading higher at high elevation sites Use of passive sampling methods and models to understand sources of mercury deposition to high elevation sites in the Western United States Huang and Gustin E i t l S i d T h l Electromagnetic Radiation Fig. 3 8 Brooks/Cole Publishing Company / ITP 25

26 Ultraviolet radiation UVA to 0.4 um longest wavelength, least energetic, can cause some damage to living cells UVB to um damaging to living cells, under normal conditions most absorbed by ozone UVC-< 0.28 highest energy shortest wavelength UV-A UV-B UV-C O 2 O 3 = O 2 + O O 2 = O + O O 2 O 2 O 2 O 2 O 2 O 2 + O =O 3 26

27 How Does Depletion Occur? CFCl3 + light Cl Cl + O3-ClO + O2 ClO + O Cl + O2 Net O + O3 2O2 Ozone Thinning Antarctic depletion in their spring which is our fall; Arctic depletion in the spring Dobson unit data 27

28 Ozone depleting chemicals Hydroxyl radical Nitric acid CFCs-Halogen containing compoundsnontoxic and non flammable Bromine containing fire retardants Methyl Bromide Carbon tetrachloride/methyl chloroform HCFCs 28

29 Elements August 2010 Particulates- solid particles and liquid droplets Aerosol- PM and the gas within which it is suspended Table 3.3 S and B Figure 3.7 Primary PM direct Secondary formed through gas to particle conversion May be altered in the atmosphere-aged 29

30 Natural versus anthropogenic sources Natural-volcanoes, ocean spray, dust storms, fires, biogenic particles Human- industrial, agriculture, traffic, mining, incineration, combustion Lost to agglomeration Cloud formation Lost to deposition 30

31 Aerosol (particulates) concentrations are increasing globally, also AOD = light extinction per unit path length due to aerosols Large-scale haze phenomena exist around the world United States East Coast 31

32 Direct Effects of Aerosol Light Absorption Light Scattering reduction in solar radiation at surface Direct Effects of Aerosol H 2 O H 2 O H 2 O H 2 O H 2 O H 2 O H 2 O H 2 O H 2 O H 2 O H 2 O H 2 O H 2 O H 2 O If too small requires too much energy required for water molecules to condense on each other 32

33 Other Effects of Aerosol Normal Atmosphere Atmosphere with Inversion Height Height Hot Air Hot Air Temperature Temperature Global Dimming Beijing, China 10-25% dimming in Beijing, Karachi, New Delhi 20% sunlight reduction since 1970 in Guangzhou 2% per decade dimming on Indian subcontinent >4% per decade dimming in China cleid=5978&l=en 33

34 Chapter 4 treatise v 4 PM and oceans Deposition of dust can have negative or positive effects Copper inhibit phytoplankton the decline of coral reefs in the Caribbean region has been linked to Saharan dust deposition-not well understood Important source of nutrients Elements Gasso, Santiago, Grassian, Vicki H., Miller, Ron L. Interactions between Mineral Dust, Climate, and Ocean Ecosystems ELEMENTS :

35 Atmospheric Deposition Dry and wet are important --- DRY not well quantified

36 Climate System humans Fourth assignment I have picked papers for you all to read. See paper picks. Read the The Global Carbon Cycle: A Test of Our Knowledge of Earth as a System Science 290, 291 (2000) P. Falkowski, et al. Place your assigned paper into the context of the Falkowski paper Same format for paper.. read summarize critique for presentation do the same but include how it fits into the older literature. Assigned people will give presentation. Maximum 1 graph on the overhead and use the board. Keep at 7 minutes. 36