Radiation, Infrared

INFRARED RADIATION IS the part of the electromagnetic spectrum popularly (but not entirely accurately) conceptualized as heat. The IR region covers wavelengths that span nearly three orders of magnitude; it is conventional therefore to break this down into further subgroups (Table 1).

The main application of IR radiation in relation to climate change is in the fields of meteorology and climatology. Satellite measurements of IR radiation received from the Earth can be used to derive cloud types and heights; these are used for weather forecasting, but knowledge of the number and type of clouds present is useful in calculating the Earths radiative budget. It is possible to use the IR radiation returned to space from the earth to measure land and sea surface temperature, both of which are important parameters in calculating the Earths heat budget and in monitoring global climate change. Satellite measurements of IR are also used to determine cloud height and rates of convection.

IR radiation also finds a variety of industrial, military, other scientific, and domestic applications, for example:

• 1.
  Night vision—Night vision devices use a photon muliplier to amplify the signal from the available ambient light which is then augmented with the IR radiation.
• 2.
  Thermal imaging—non-contact, non-destructive technique that generates a false-color thermal image of a subject finding a wide range of industries.
• 3.
  Heating—IR lamps can be used for heating; examples include for frozen aircraft wings and for patio heaters.
• 4.
  Spectroscopy—IR spectroscopy (also called rotational spectroscopy) is a technique used by chemists for the identification of molecules and for elution of chemical structure.