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Oxygen: Stratosphere, Mesosphere and Thermosphere Part-3 Chemical Rate Equations Ozone Density vs. Altitude Stratospheric Heating Thermal Conductivity.

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Presentation on theme: "Oxygen: Stratosphere, Mesosphere and Thermosphere Part-3 Chemical Rate Equations Ozone Density vs. Altitude Stratospheric Heating Thermal Conductivity."— Presentation transcript:

1 Oxygen: Stratosphere, Mesosphere and Thermosphere Part-3 Chemical Rate Equations Ozone Density vs. Altitude Stratospheric Heating Thermal Conductivity Thermospheric Structure Temperature Structure on other planets

2 n1n1 Rate Equations for Oxygen Chemistry

3 Introduce Ozone

4 Ozone continued

5 Dependence on z Remember: J 2 (z) = J 2 o exp[ -  2 (z)/  ] where  = cos   2 (z) =  abs  o  n 2 dz n 2 (z)  0.21 n M n M (z) = n M (0) exp(-z/H) in mixed region J 3 (z) = J 3 o exp[ -  3 (z)/  ] For  3 (z) need n 3 (z) which we are solving for.

6 10 -9 /s 10 -2 /s 20 80 40 80 mesopause … stratopause Tropopaus n 3, T J2J2 J3J3 n3n3 T High z J 2 /J 3 =constant ~10 -7 Low z J 2 /J 3 --> 0

7 Densities of O 2,O 3 and O C+H To get right: need some diffusive separation in the upper regions At night: J 2 (z) and J 3 (z) --> 0 ‘slow’ reactions become important High z n 1  1/n 2 1/2 n 3  n 2 3/2 Log 10 n(mol/cc)

8 Temperature vs. Altitude Earth’s Atmosphere Stratospheric Heating peak and Ozone Peak related J 3 (z) = J 3 o exp[ -  3 (z)/  ] dT/dt  h 3 J 3 (z) n 3 (z)

9 Summary

10 EUV Thermal conduction mesopause I R Thermosphere + Ionosphere Z 130km 80km

11 F s (z) zz  T +  TT zz

12 Thermosphere Continued

13 Thermosphere T Structure T m is where the heat conducted downward is radiated to space Relation to our old T e ?

14 Thermosphere Structure (Cont)

15 y(x) =  o x { [1-exp(-x’)]/x’} dx’ x   (z); y   T 7/4 Integral for thermosphere model

16 Temperature vs. Altitude Earth’s Atmosphere Rise in T in Thermosphere due to EUV Absorption and Thermal Conduction to Mesopause These are averages Tropopause is higher and hotter Near equator ~16-18km and ~ 10km near poles Drives high altitude horizontal flow Jets ~10km to be close to stratosphere and avoid turbulence

17 A result of Horizontal Transport Ozone column density in ppm Tropopause higher near equator and lower in T Drives upper atmospheric flows Will treat horizontal transport soon

18 Noctilucent Clouds (night shining clouds, ~85km, ice grains) (polar mesospheric clouds) over a lake in northern Sweden Possibly produced by climate change and space shuttle exhaust Polar Stratospheric (nacreous)Clouds ~15-25km: ice, nitric and sulfuric acids Implicated in ozone holes

19 Polar Stratospheric (nacreous)Clouds ~15-25km: ice, nitric and sulfuric acids Implicated in ozone holes Polar Stratospheric (nacreous)Clouds

20 Earth’s Thermal Structure dePL Thermosphere T depends on Solar Activity

21 Venus Atmosphere dePL Cloud Tops --> T e CO2 even at high altitudes --> cooling Slow Rotation 1 year = 2 days (retrograde due to thickatmosphere and tidal forces?)

22 Mars Atmosphere dePL T e at Surface Dust absorbs h and changes the lapse rate Thermosphere strongly dependent on solar activity

23 Photo-chemistry Venus + Mars CO 2 + h  CO + O (1) CO+O+M  CO 2 + M (2) (2) is very slow at Mars (density of M Is very small): Expect considerable CO, especially so as free O oxidize surface (iron oxide) But there is a small amount of H2O H 2 O + h  OH + H (3) CO + OH  CO 2 + H (4) On Venus CO --> CO 2 may be aided by sulfur + chlorine species

24 Titan’s Atmosphere dePL Stratosphere/ mesosphere due to absorption in hydrocarbon haze CH 4 + h -> CH 3 +H(CH f +H 2 ) React to form C n H m and H 2 escapes. Thermosphere subject to particles from Saturn’s magnetosphere

25 Giant Planets dePL Internal heat sources Adiabatic lapse rate down to liquid metal hydrogen Jupiter has evidence of a stratosphere and a mesosphere

26 Typically troposphere (Lower, Convective) Mesosphere [ Stratosphere ] (Middle, Radiative) Thermosphere (Upper, Conductive) Exosphere (Escape) Venus Temperature Lapse,   d Tropopause at cloud layer (~ 70 km) T e ~ Top of cloud layer Thermosphere (Cryosphere) T d ~ 300 km (CO 2 at high altitudes) T n ~ 100 km (Slow rotation 1yr  2 days) Mars Temperature Lapse    d (Strong Day / Night Variations: Dust    d Mesosphere T < Te (CO 2 cooling) Thermosphere like Mesosphere (Strongly affect by solar activity) Titan Temperature Lapse    d Stratosphere (Haze Layer) Mesosphere (Cooler to space) Thermosphere (Solar UV + Energetic Particles from Magnetosphere Cooled by HCN, Slow Rotations) Grant Planets Internal heat source comparable to solar Tropopause ~ 0.1 bar,  ~  d, Temperature + pressure increase to about 2M bar so phase change to a liquid (metallic) state (4x10 4 km) and a metallic core (3x10 4 K) (1x10 4 km) (Jupiter) Mesosphere (stratosphere)  0.001 bar Hydrocarbon coolants Thermosphere (Solar EUV) Atmosphere Thermal Structure: Summary

27 #3 Summary Things you should know Earth’s thermal structure Rate equations Oxygen reactions Ozone layer Stratosphere Mesosphere Thermosphere Thermal conductivity Heat flux


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