Atmospheric Radiation



  Amospheric Radiation 2 071106.pdf (Size: 2.86 MB / Downloads: 0)

Introduction

• The major source of earth is the sun.
• The sun transfer energy through the earth by radiated
electromagnetic wave.
• In vacuum, electromagnetic waves travel at speed of light (300,000
km/s).
• The continuous electromagnetic spectrum distinguishes different
types of waves based on wavelength and frequency.


Heat Transport in Atmosphere

• Transport of heat is accomplished by conduction,
convection and radiation
– radiation: energy transfer which can take place in a vacuum, with
no intervening physical medium (unlike conduction and
convection)
– conduction: transfer of kinetic energy of molecules by collisions
of molecules
– convection: transport of heat within a fluid by bulk motion of fluid
itself
• heat transported by conduction and convection is
"sensible heating"


Basic Concepts

• The subject of atmospheric radiation is concern with the transfer
energy within the atmosphere by photons, or equivalently by
electromagnetic wave.



Solar radiation
• solar radiation is emitted from solar
photosphere (surface of sun), at a
temperature of 5800 K
• it is most intense at a wavelength of
about 0.5 microns (micrometer), which
lies in the visible part of the
electromagnetic spectrum