Detection of thermal changes possibly associated with volcanic activity and discrimination of faint changes from MODIS

To mitigate volcanic hazards, a new algorithm for monitoring volcanic activity using satellite remote sensing in mid-infrared range (MODIS) has been developed. Nighttime data of Band 20 is used for brightness temperature imaging, and data at Bands 31 and 32 are analyzed for attempting to remove the cloud effects. It is found that a certain threshold is effective for cloud detection in the tropical region. Moreover, the differential brightness temperature (S and Smax) between the focused and the reference points is introduced to eliminate the background effects. In addition, the singularity of the differential bright temperature in time (δ and δmax) has been proposed. The developed algorithm has been applied to the practical data associated with the Mt. Merapi volcano in Java, Indonesia and the Mt. Asama volcano in Honshu, Japan. In the case of Mt. Merapi volcano, the results suggest the effectiveness of the developed method. For the case of Mt. Asama, the proposed method cannot remove the cloud influences.

► A new algorithm for monitoring volcanic activity using satellite remote sensing in mid-infrared range (MODIS) is proposed.
► Nighttime data of Band 20 is used for brightness temperature imaging, and data at Bands 31 and 32 are analyzed for removing the cloud effects.
► It is found that a certain threshold is effective for cloud detection in the tropical region.
► The differential brightness temperature between the focused and the reference points and the singularity of the differential bright temperature in time are useful.