April 15, 2021

"La Soufrière" – EOC monitors distribution of the sulpher dioxide plume

On Friday, April 9, 2021, "La Soufrière" volcano erupted on the Caribbean island of St. Vincent. Since that time, EOC has been monitoring the spread of volcanic emissions, which in the meantime extend over ten million square kilometres, about the area of Canada. This information helps prevent air traffic from entering an airspace that is potentially dangerous for people and aircraft.

"La Soufrière" – EOC monitors distribution of the sulpher dioxide plume

In addition to the spread, scientists at EOC have ascertained the elevation and total amount of sulphur dioxide (SO2) that was emitted. So far, over 500,000 tonnes of this gas have been released.

Sulphur dioxide is a naturally occurring trace gas in Earth’s atmosphere, increased primarily by emissions from the combustion of fossil fuels in power plants and industrial facilities. Sulphur dioxide also enters the lower troposphere in volcanic emissions, and even the stratosphere in the case of explosive eruptions.

The Sentinel-5P satellite takes daily measurements of the global distribution of important trace gases like sulphur dioxide, ozone and nitrogen dioxide. The UV spectrometer TROPOMI on Sentinel-5P provides what is for atmospheric measurements the very high spatial resolution of 3.5 x 5.5 kilometres, which even permits the identification of individual emission sources, such as coal-fired power plants or steel mills.

The detection of SO2 sources can also indicate an imminent volcanic eruption. Volcanic emissions not only endanger their immediate surroundings but can also be dangerous for passengers and even the engines of aircraft passing by.

The methods employed while monitoring "La Soufriere" for altitude determination and for visualising sulphur dioxide emissions are also being developed and optimised at DLR as part of DLR’s "inpuls" project and in the ESA Sentinel-5p+ innovation project, as well as for other purposes.