Identification of volcanic ash and sulfur dioxide plumes from satellite imagery

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• Quantitative measurements from space
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• Optical absorption spectrometers
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• Infrared spectrometers
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• Space based Lidar instruments

3.3 Space based Lidar instruments

The vertical extent of volcanic ash plumes is an important factor in aviation. Lidar instruments such as CALIOP, which are carried by LEO satellites, are active instruments that provide a vertical profile of clouds and aerosols.

The main purpose of lidar instruments is measuring cloud height from above. While this works well for regular clouds that consist of water droplets or ice crystals, ash clouds can be much more dense, in which case the lower atmospheric levels are shielded by particles in the top layers of the ash plume (Figure 26).

Figure 26: The eruption plume of Mount Kelud on 13 February 2014. © NASA Earth Observatory, Jesse Allen.

More about volcanic ash and SO₂ cloud monitoring:

• NOAA/CIMSS
• VAAC London
• SO₂ total column from IASI