• <Wavelength_Keyword> is a designated keyword describing a spectral or frequency range in which the instrument operates. For example, <Wavelength_Keyword>Microwave</Wavelength_Keyword>
  • Radio
  • Microwave
  • Infrared > Reflected
  • Infared > Thermal
  • Near Infrared
  • Visible
  • Ultraviolet
  • X-Ray
  • Gamma Ray
• <Number_Channels> is the number of spectral channels or frequencies in which the instrument operates at the wavelength specified by the <Wavelength_Keyword>. The instrument can contain any number of channels or frequencies. For example, <Number_Channels>20</Number_Channels>
• <Spectral_Frequency_Coverage_Range> is the spectral coverage or frequency range of the instrument for a particular wavelength as specified by the <Wavelength_Keyword>.
  • For optical and infrared instruments, the range is usually expressed in micro or nano-meters. For example, <Spectral_Frequency_Coverage_Range>0.3 - 1.1um</Spectral_Frequency_Coverage_Range>.
  • For microwave or radar instruments, it is usually expressed in MHz or GHz. For example, <Spectral_Frequency_Coverage_Range>10.8-89 GHz </Spectral_Frequency_Coverage_Range>.
• <Spectral_Frequency_Resolution> represents the capability of an instrument to resolve signals in the electromagnetic (EM) spectrum. It is usually the smallest difference in wavelength or frequency that can be distinguished by the instrument. For example, <Spectral_Frequency_Resolution>50 nm </Spectral_Frequency_Resolution

<Spectral_Frequency_Information>
<Wavelength_Keyword>wavelength keyword</Wavelength_Keyword>
<Number_Channels>integer number or text</Number_Channels>
<Spectral_Frequency_Coverage_Range>real number or text </Spectral_Frequency_Coverage_Range>
<Spectral_Frequency_Resolution>real number or text </Spectral_Frequency_Resolution>
</Spectral_Frequency_Information>

* The subfields <Number_Channels>, <Spectral_Frequency_Coverage_Range>, and <Spectral_Frequency_Resolution> may contain 1 to 80 characters. Characters include the entire printable UTF-8 character set.

• This field is highly recommended and may be repeated per <Wavelength_Keyword>.
• The following <Spectral_Frequency_Information> fields are highly recommended and may not be repeated:
  • <Wavelength_Keyword>
  • <Number_Channels>
  • <Spectral_Frequency_Coverage_Range>
  • <Spectral_Frequency_Resolution>
• The <Wavelength_Keyword> must be selected from the <Wavelength_Keyword> keywords. See Appendix A.
• Please specify units with <Spectral_Frequency_Coverage/Range> and <Spectral_Frequency_Resolution>. Some examples: Å(Angstroms), µm (use Greek symbol here (micrometers), nm (nanometers), M (MHz), G (GHz).

[Example taken from Ozone Measuring Instrument (OMI). There are 2 UV and 1 VIS channel on OMI.]
<Spectral_Frequency_Information>
<Wavelength_Keyword>Ultraviolet</Wavelength_Keyword>
<Number_Channels>2</Number_Channels>
<Spectral_Frequency_Coverage_Range>270-380 nm</Spectral_Frequency_Coverage_Range>
<Spectral_Frequency_Resolution>0.63-0.42 nm</ Spectral_Frequency_Resolution>
</Spectral_Frequency_Information>
<Spectral_Frequency_Information>
<Wavelength_Keyword>Visible</Wavelength_Keyword>
<Number_Channels>1</Number_Channels>
<Spectral_Frequency_Coverage_Range>350-500 nm</Spectral_Frequency_Coverage_Range>
<Spectral_Frequency_Resolution>0.63-0.42 nm
</Spectral_Frequency_Resolution>
</Spectral_Frequency_Information>