Perturbations in atmospheric gaseous components over coastal Antarctica detected in GPS signals and its natural origin to volcanic eruption

Abstract

Although the variations in atmospheric water content control the perturbations in total travel time delay experienced by GPS signals during passage through the atmosphere (ZTD-Zenith Total Delay), significant changes in ZTD can also occur due to anomalous high influx of dry components into the atmosphere during massive volcanic eruptions. Such a possibility is illustrated here by analyzing GPS data from different locations around the Antarctic continent during the massive eruption of Mt. Chaiten volcano in Chile on 19th, February 2009. GPS derived ZTD values showed abnormal perturbation during the transition from summer to winter time in Antarctic margins. The irregular ZTD values, which existed for the short period from 19th, February to 08th, March 2009, exhibited perturbations and showed high correspondence with the abnormal atmospheric black carbon (BC) content noticed over the Indian Antarctic station (Maitri) during the same period. We therefore suggest that the anomalous ZTD changes might have resulted due to high BC influx into the atmosphere. We propose that the 19th, February 2009 massive eruption of Mt. Chaiten is the source for the BC, which moved from the volcanic front to the East Antarctica margin along with the circum polar current.