AVHotRR: near-real time routine for volcano monitoring using IR satellite data.

The AVHotRR routine has been in operation since 2006 to process satellite data for
monitoring active volcanoes in the Mediterranean area. Although originally developed to work
with advanced very high-resolution radiometer (AVHRR) data, AVHotRR has been developed
over the years to adapt to other sensors. In this work we present an improved version of the algorithm
for hot-spot detection and effusion rate estimate. The underlying principles upon which the
algorithm is based are discussed, focusing on the enhancements. The currently implemented version
makes it possible to integrate results from different datasets in order to better constrain the
detection of volcanic hot spots. In particular, the high temporal resolution of the SEVIRI instrument
aboard MSG is key to reducing false positives in AVHRR and moderate resolution imaging
spectroradiometer MODIS images. We propose here a new detection method based on the wavelet
transform of SEVIRI data. Results from the application of AVHotRR to a dataset of AVHRR and
SEVIRI images from Mt Etna, Italy, are presented and discussed with reference to the advantages
and limitations of the algorithm.