AVHRR is one of several instruments on NOAAs operational polar-orbiting meteorological satellites. AVHRR observes radiance from Earth at five wavelengths spanning the visible to thermal infrared portions of the spectrum (see Table 1).
|AVHRR Channel||Wavelength (µm)|
|1||0.58 - 0.68|
|2||0.72 - 1.10|
|3||3.55 - 3.93|
|4||10.3 - 11.3|
|5||11.5 - 12.5|
Note that channels 3, 4, and 5 are in the infrared atmospheric windows and therefore can be used to observe the sea surface with minimal atmospheric interference. The exception to this rule is when clouds are present. The following sections discuss this problem.