An initial comparison of the thermal anomaly detection products of MODIS and VIIRS in their observation of Indonesian volcanic activity

The Suomi National Polar-orbiting Partnership satellite was launched in 2011. On-board this satellite is the Visible Infrared Imaging Radiometer Suite (VIIRS) with thermal infrared detection capabilities similar to those of the earlier Moderate-Resolution Imaging Spectroradiometer (MODIS) sensors of the National Aeronautics and Space Administration Earth Observation System. Fire detection products have been developed using the thermal infrared data for both VIIRS and MODIS and, although having the observation of fire as their main objective, such products are also sensitive to the radiant emissions of active volcanic surfaces, but a comparison of their capabilities in this regard remains outstanding. Here, this comparison is conducted, with a focus on the volcanoes of Indonesia, and findings are initially promising, suggesting that the VIIRS fire detection capability is an improvement over that of its predecessor. For example, between 3 April 2012 and 14 July 2014, volcanic activity was detected on 519 days by the VIIRS product, as compared with 308 days for the MODIS-Aqua product (MYD14). Causes of this apparent enhanced sensitivity are explored and, with the examination of additional data from the MODIS-Terra product and the MODVOLC system, are shown to be the combined influence of spatial resolution, data processing steps, imaging scan width and the fire product algorithm used. As greater quantities of data become available, a more comprehensive comparison of these observations will be possible and will be undertaken at a global scale.