Synergy between COSPEC observations and MODIS images in the monitoring of volcanic SO2

Volcano monitoring is developed mainly with remote sensing techniques. In the case of SO2, it has been strongly used both surface techniques, such as COSPEC, and satellite techniques, such as MODIS. The two techniques differ in their measurement principle presenting advantages and disadvantages to each other. The purpose of this work is to show the synergy of both remote sensing methods in order to utilize information derived from these two techniques for continuous volcano monitoring. In this communication, we propose a methodology to correct any lag between COSPEC measurements and MODIS images at either time or space based on the wind speed and difference of the exact time of acquisition between the two techniques. The difference observed between COSPEC data and MODIS estimates is removed by using an exponential regression function derived from simultaneous observations using both sensors.