资源环境科技发展态势分析平台

Satellite remote sensing is a valuable method for detecting and quantifying sulfur dioxide (SO2) emissions at volcanoes. The use of ultraviolet satellite instruments for monitoring purposes has been assessed in numerous studies, but there are advantages to using infrared measurements, including that they can operate at night and during high-latitude winters. This study focuses on the Infrared Atmospheric Sounding Interferometer (IASI). Retrievals developed for this instrument have been shown to be successful when applied to large eruptions, but little has been done to explore their potential for detecting and quantifying emissions from smaller and lower altitude emissions or for the assessment of ongoing activity. Here a fast linear retrieval has been applied across the globe to detect volcanic sources of SO2. The results are dominated by emissions from explosive eruptions, but signals are also evident from weak eruptions, passive degassing, and anthropogenic activity. Ecuador and Kamchatka were selected for further study with a more processing intensive iterative retrieval which can quantify the SO2 amount. At Tungurahua in Ecuador, good agreement was seen between IASI, the Ozone Monitoring Instrument (OMI) and ground-based flux data, demonstrating that the retrieval is capable of capturing relative changes in activity. Similarly, good agreement was found between IASI and OMI in Kamchatka. In this high-latitude region, OMI is unable to operate for 3 or 4months in each year. It is therefore suggested that IASI could be used alongside other instruments for evaluating changes in volcanic activity.

Plain Language Summary Gas emissions at volcanoes are dangerous to health and can alter the environment and climate. Monitoring the gases emitted is therefore important, and it gives volcanologists some insight into volcanic behavior. Ground-based monitoring can be dangerous and is limited in remote regions, and so satellite imagery is used to detect and measure volcanic gas emissions (usually sulfur dioxide [SO2]) across the globe. This study focused on the Infrared Atmospheric Sounding Interferometer, which is an infrared sensor onboard two meteorological satellites. First, a fast tool was used to detect emissions of SO2 across the globe: including from explosive volcanic activity, smaller eruptions, and human pollution sources. Following this, a second method was applied to calculate the amount of SO2 emitted from volcanoes in Ecuador and Kamchatka (Eastern Russia)two regions with regular volcanic activity. This technique was shown to capture changing levels of volcanic activity in both areas. At Tungurahua, a volcano in Ecuador, comparisons could be made to another satellite and to measurements made on the ground. The three methods compared well suggesting that the technique developed for Infrared Atmospheric Sounding Interferometer can capture changing activity at this volcano and could be valuable for tracking and quantifying emissions.