Biosphere atmosphere interactions biology 164 264
Download
1 / 23

Biosphere/Atmosphere Interactions Biology 164/264 - PowerPoint PPT Presentation


  • 36 Views
  • Uploaded on

Biosphere/Atmosphere Interactions Biology 164/264. 2007 Joe Berry joeberry@globalecology.stanford.edu Chris Field cfield@globalecology.stanford.edu Adam Wolf adamwolf@stanford.edu. Basic questions to be addressed by this course:.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' Biosphere/Atmosphere Interactions Biology 164/264' - nola-harrison


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
Biosphere atmosphere interactions biology 164 264

Biosphere/Atmosphere InteractionsBiology 164/264

2007

Joe Berry joeberry@globalecology.stanford.edu

Chris Field cfield@globalecology.stanford.edu

Adam Wolf adamwolf@stanford.edu


Basic questions to be addressed by this course
Basic questions to be addressed by this course:

  • What are the major fluxes of energy and matter between the atmosphere and land ecosystems?

  • What determines the temperature of leaves, plants, soils, and ecosystems?

  • What controls rates of plant photosynthesis and transpiration?

  • How do atmospheric processes interact with ecosystem processes to control CO2 and water exchanges?

  • How do characteristics of the land surface influence the motions of the atmosphere?

  • How do characteristics of the land surface influence climate?

  • How do greenhouse gases exchanged by ecosystems influence climate?

  • How can we measure and model the exchanges of matter and energy from the leaf to the global scale?


Mechanics
Mechanics

  • 2 lectures per week – TTh 11-11:50

    • Bio T 185

  • 1 lab per week – Tuesday 2-5

    • Carnegie Global Ecology (260 Panama Street)

  • 1 optional Matlab/problem session – Thursday 4-6

    • Carnegie Global Ecology (260 Panama Street)

  • Grading:

    • Bio 164:

      • Weekly problem/program 60%

      • Final project data analysis 20%

      • Class participation 10%

      • Labs (weekly data sets) 10%

    • Bio 264:

      • Weekly problem/program 40%

      • Final integrated program 20%

      • Final project data analysis 20%

      • Class participation 10%

      • Labs (weekly data sets) 10%

    • Problem/programs in Matlab

    • No midterm, no final, no papers


Biosphere atmosphere interactions biology 164 264
Labs

  • January 16

    • Principles of environmental sensors & data loggers

    • Radiation sensors

  • January 23

    • Environmental sensors – wind, humidity, soil moisture, water potential

  • January 30

    • Environmental sensors – CO2, water vapor

  • February 6

    • Leaf gas exchange

  • February 13

    • Leaves – fluorescence, spectral reflectance, isotope exchange

  • February 20

    • Canopy gas exchange – eddy flux hardware

  • February 27

    • Canopy gas exchange – environmental conditions at an eddy flux installation

  • March 6

    • Canopy gas exchange – vegetation status and fluxes at an eddy flux installation

  • March 13

    • Canopy gas exchange – setting up an eddy flux system

  • For each lab, each pair will be responsible for collecting, analyzing, and turning in a data set collected from at least one sensor or system


Texts
Texts

  • Campbell, G. S. and J. M. Norman. 1998. An Introduction to Environmental Biophysics. Springer, New York. 286 pp. (core)

  • Hartmann, D. L. 1994. Global Physical Climatology. Academic Press, San Diego. 411 pp. (optional)

  • Stull, R. B. 2000. Meteorology for Scientists and Engineers. Brooks Cole, Pacific Grove. 503 pp. (optional)

  • Bonan, G. B. 2002. Ecological climatology: Concepts and applications. Cambridge University Press, New York. 678 pp. (optional)



Biosphere atmosphere interactions biology 164 264

What controls the temperature of the planet?

Heat-trapping or greenhouse gases trap thermal radiation on its way to space.

Energy in = Energy out + storage


What controls rates of photosynthesis
What controls rates of photosynthesis?

Annual weeds

Deciduous trees

Photosynthetic capacity

Evergreen sclerophylls

Leaf nitrogen






Radiation
Radiation

  • All objects at temperatures above absolute zero emit radiation.

  • Photons carry a unique amount of energy that depends on wavelength

  • E = hc/l

  • Where h is Planck’s constant (6.63*10-34 Js), c is the speed of light (3*1010m s-1), and l is wavelength (m).


Thermal radiation
Thermal Radiation

  • Stephan-Boltzmann Law

  • s = 5.67 * 10-8 W m-2 K-4

  • Earth approximates a black body at 288 K -- Emits 390 W m-2

  • Black body = emissivity () = 1

  • Note: the emissivity of plants is close to 1, but other objects can have very different values


Absorptance and emissivity
Absorptance and Emissivity

  • Absorbed radition is proportional to absorptance

  • Emitted radiation in proportional to emissivity = absorptance


Blackbody radiation
Blackbody radiation

  • Amount increases with T4

  • Wavelength of maximum proportional to 1/T


Wien law
Wien Law

  • objects at 300k maximum emission at about 10 micrometers


Solar energy
Solar energy

  • Solar output 3.84*1034 W

  • extra-atmosphere – the sun is close to a 5760 K black body

  • radiant emittance = 6.244*107 W m-2

  • most of the solar energy is in the range of 0.3 – 2.5 micrometers

  • about 50% is visible (0.4 – 0.7m) and about 50% is infrared (> 0.7m)

  • The solar (not so) constant

  • Integrating this emittance over the size of the sun and the distance to the earth leads to a radiation at the outside of the atmosphere of 1360 W m-2

  • Integrating over the spherical surface leads to an average radiation of about 342 W m-2



Atmospheric transmission
Atmospheric transmission

  • Absorption

    • Average absorption by the atmosphere 62 W m-2

  • Scattering

    • Raleigh (small particle) – shortest wavelengths scattered preferentially out of the solar beam

    • Mie (large particle) – little wavelength dependence

    • Average reflected solar radiation by the atmosphere 77 W m-2

  • Effects of clouds

  • Scattering and reflectance

  • The greenhouse effect

    • Increased absorptance of thermal radiation means increased radiation directed back to the surface

    • Increased absorptance in the atm effectively increases the height at which the atmosphere is radiating back to space