About this exercise type...

The Sun is not a perfect light source for remote sensing applications for a number of reasons:

• Absorption in the solar atmosphere leads to the presence of a large number of _ lines.
• The _ year solar cycle affects radiation and is particularly relevant at short wavelengths shorter than _ nm.
• The radiation spectrum _ over the solar disk.
• The rotation of the Sun causes a _ shift.
• The intensity of the radiation varies as a result of changes in _ between the Sun and the Earth.

The solar spectrum can be approximated by a _ at a temperature of _ K.

As solar radiation passes through the Earth's atmosphere it is strongly absorbed at certain wavelengths particularly by O₃, O₂, H₂O and CO₂. However, there are some wavelength regions where absorption is small; these are known as atmospheric or radiation '_'.