Effect of the 2021 Cumbre Vieja eruption on precipitable water vapor and atmospheric particles analysed using GNSS and remote sensing

The eruption of Mount Cumbre Vieja, La Palma, Spain, on 19^th September 2021 released large amounts of gas and volcanic ash into the atmosphere that spread over hundreds of kilometers. Subsequently, the volumes of gaseous, and water vapor components in the troposphere were highly disturbed. In general, the release of a large amount of water vapor during an eruption increases the value of path delay and vertical column density of SO₂. Therefore, this study analyzed their variations to determine the impact of eruption. The precise point positioning on Global Navigation Satellite System (GNSS) observation data were processed to obtain zenith tropospheric delay (ZTD) and precipitable water vapor (PWV) contents, while Sentinel 5P, and MODIS remote sensing imagery were used to determine SO₂ column density, aerosol index, and surface temperature. Moreover, time series and correlation analysis were computed to analyze the effect of the eruption and the relationship between GNSS and remote sensing parameters. Our findings showed that the variations in precipitable water vapor affected the ZTD value for three GNSS stations around the eruption point, showing a correlation value above 0.98. Meanwhile, the remote sensing data indicated that the SO₂ content peaked at the end of September and in October 2021. Similarly, tropospheric delay, and water vapor had the highest fluctuations and increases in the early eruption period. However, the lower atmosphere layer was generally influenced by the autumn climate. The content of particles released into the atmosphere during eruption had minor effect in the middle to the end of the eruption period as rainfall events led to an increase in water vapor. The surface temperature was found to be characterized mostly by autumn condition but showed fluctuations and increased values in the early period of the eruption.