ATMOS 5140 Lecture 1 Chapter 1

Transcription

1 ATMOS 5140 Lecture 1 Chapter 1 Atmospheric Radiation Relevance for Weather and Climate Solar Radiation Thermal Infrared Radiation Global Heat Engine Components of the Earth s Energy Budget Relevance for Remote Sensing

2 Processes in Atmosphere Adiabatic Last class no heat exchange Diabatic Thermal Conduction - Surface of the Earth Latent heating and cooling - Covered in last class Atmospheric Radiation Generally important only near the ground surface and within some clouds. Radiative heating and cooling lead to the formation of daytime low-level instability and nocturnal lowlevel stability, respectively. Radiative processes in the free air and at cloud tops, however, are slow and their effect on the lapse rate are generally minimal.

3 Solar or Shortwave Radiation Thermal or Longwave Radiation

4 Blackbody Radiation Solar Radiation Thermal Radiation

5 Blackbody Radiation Solar Radiation Thermal Radiation

6 Solar Radiation

7 Global Heat Engine Annual Average Radiative Flux Outgoing Longwave Radiation Absorbed Solar Radiation Net Radiation 200 Flux (W m -2 ) Deficit Surplus Deficit Latitude

8 Global Heat Engine Annual Average Radiative Flux Outgoing Longwave Radiation Absorbed Solar Radiation Net Radiation Tropics More solar received than lost in Longwave Flux (W m -2 ) Deficit Surplus Deficit Latitude

9 Global Heat Engine Annual Average Radiative Flux Outgoing Longwave Radiation Absorbed Solar Radiation Net Radiation Tropics More Solar received than lost in Longwave Radiation Flux (W m -2 ) Deficit Surplus Deficit Poles More lost in Longwave Radiation than received in Solar Latitude

10 Global Heat Engine Annual Average Radiative Flux Outgoing Longwave Radiation Absorbed Solar Radiation Net Radiation Tropics More Solar received than lost in Longwave Radiation Flux (W m -2 ) Surplus 0-50 Deficit Deficit Latitude Poles More lost in Longwave Radiation than received in Solar Creates a Meridional Temperature gradient Heat Transfers from Hot to Cold Recall the heat engine temperature gradient is transferred to mechanical work

11 Earth's Energy Budget Incoming solar energy 100% Reflected by atmosphere 6% Reflected by clouds 20% Reflected from earth's surface 4% Radiated to space from clouds and atmosphere Absorbed by atmosphere 16% Absorbed by clouds 3% Conduction and rising air 7% 64% 6% Radiated directly to space from earth Radiation absorbed by atmosphere 15% Atmosphere is responsible for radiating ~90% of total absorbed solar energy back to space!! Absorbed by land and oceans 51% Carried to clouds and atmosphere by latent heat in water vapor 23%

12 Application of Remote Sensing

13 NASA A-TRAIN

14 Satellite Orbits Geosynchronous ~36,000 kilometers from Earth s surface Orbit Matches Earth s orbit moves same speed as earth Weather Monitoring See one spot Lagrange points Pull of gravity from the Earth cancels out the pull of gravity from the Sun 1.5 million kilometers away from Earth! Medium Earth Orbit Semi-synchronous orbit 26,560 kilometers from the center of the Earth GPS orbit Low Earth Orbit Sun-synchronous orbit Regular adjustments to maintain a satellite in a Sun-synchronous orbit.

15 Satellite Orbits Geosynchronous ~36,000 kilometers from Earth s surface Orbit Matches Earth s orbit moves same speed as earth Weather Monitoring See one spot

16 Satellite Orbits Lagrange points Pull of gravity from the Earth cancels out the pull of gravity from the Sun 1.5 million kilometers away from Earth!

17 Satellite Orbits Medium Earth Orbit Semi-synchronous orbit 26,560 kilometers from the center of the Earth GPS orbit

18 Satellite Orbits Low Earth Orbit Sun-synchronous orbit Regular adjustments to maintain a satellite in a Sun-synchronous orbit.

19 a) Visible, 0.65 µm b) IR window, 10.7 µm GOES IMAGE c) IR water vapor band, 6.7 µm Use IR window to see temperature gradient