Analysis the Cloud Properties Using NOAA/AVHRR Data

The brightness temperature (BT) of NOAA/AVHRR CH3 (3.55~3.93μm), CH4 (10.3~11.3μm) and CH5 (11.5~12.5μm) and their differences between CH3 and CH4 (BTD34) and between CH4 and CH5 (BTD45) can be used to analyze the cloud properties. It is shown that in the case of opaque cloud or cloudless, BTD (BTD34 or BTD45) has a minimum value, in the case of dense cloud, BTD34 would be negative, and while cloud is semitransparent, BTD has bigger value. Moreover, the BTD between channels would be bigger with increasing amplitude of temperature difference scatter diagram between cloud and background surface.