Tavurvur Volcano, Paua New Guinea
​Tavurvur volcano, Papua New Guinea
​Credit: Santiago Arellano

Measuring volcano gases with drones: Chalmers scientists test new techniques in Papua New Guinea

​Using drones, Chalmers scientists have successfully measured total carbon dioxide (CO2) and sulfur dioxide (SO2) emissions from active volcanoes in Papua New Guinea. The new measurement strategy shows that safe measurements of high altitude plumes at risky volcanoes are now becoming possible.
​During September 2016, Bo Galle and Santiago Arellano from the Optical Remote Sensing group were part of a scientific mission to Papua New Guinea, sponsored by the international project Decade (Deep Carbon Degassing), to determine the total emission of carbon dioxide and sulphur dioxide from the volcanoes Tavurvur, Bagana and Ulawun.
Measuring these gases is important because of their impact on climate change and as part of volcanic risk assessment. Satellite observations have identified Bagana volcano as one of the world’s more persistent sulfur dioxide emitters, but due to its remote location it has no ground monitoring. Bagana, and other volcanoes in Papua New Guinea and elsewhere, is too high and active to perform in-situ measurements on the crater rim without tremendous risk. The best option until now has been to study the gas emissions by expensive and dangerous sampling from manned research aircrafts.

Chalmers has pioneered the development of optical remote sensing instruments to measure the flux of volcanic sulfur dioxide and coordinates a network, Novac, which presently involves instruments at nearly 40 volcanoes around the world. In contrast to sulfur dioxide, which can be measured remotely, estimates of the volcanic carbon dioxide output rely on in-situ measurements of the CO2/SO2 ratio in the volcanic plume, combined with the remotely sensed sulfur dioxide flux.

To achieve the goal of the Papa New Guinea mission in a cost-effective and safe way, the Chalmers group performed tests with a drone powerful enough to reach the volcanic plume at around two kilometres altitude containing compact CO2 and SO2 sensors. The system was successfully demonstrated at Bagana (1750 m) and Ulawun (2334 m), while the crater of Tavurvur (223 m) was accessible for direct sampling by foot. The group also installed an instrument for permanent monitoring of sulfur dioxide at Tarvurvur, operated by the local Rabaul Volcano Observatory in Papua New Guinea.

- We are currently processing the data from the campaign. Although Bagana is not as active as it was two years ago, it still emits several thousands of tons of SO2 and CO2 into the atmosphere every day. While Ulawun is a bit more active than we anticipated Tavurvur shows very little emissions but it is important to support the work of the local observatory on this volcano due to high risk posed on the local population, says Santiago Arellano.

Now the Chalmers scientists are compiling historical data from several volcanoes in the Novac network, an important contribution to a new synthesis of global volcanic gas emissions planned for next year within the Decade collaboration. Data from this project will then become available through publicly accessible databases, Bo Galle explains.

– Thanks to our new strategy, Santiago adds, new opportunities are now opening up for monitoring emissions from several high-altitude volcanoes where direct measurements are difficult or impossible to perform.

The study was sponsored by the Decade project, an international initiative part of the global research program Dco (Deep Carbon Observatory) aiming at significantly improving the measuring of global flux of carbon from volcanoes, and also involved scientists from Cambridge (UK), Palermo (Italy), Heidelberg (Germany) and the local Rabaul Volcano Observatory (Papua New Guinea).

Contacts:
Bo Galle, Professor, Optical Remote Sensing research group, Chalmers University of Technology, bo.galle@chalmers.se, +46-31 772 56 54

Santiago Arellano, Postdoctoral Researcher, Optical Remote Sensing research group, Chalmers University of Technology, santiago.arellano@chalmers.se, +46 31 772 15 89

Pictures:
1. Bagana volcano Papua New Guinea. Credit: Bo Galle, Chalmers
2. The drone sent towards a volcano during the scientific mission. Credit: Kila Mulina, Rabaul Volcano Observatory (Papua New Guinea)

For more information about:
Tavurvur
Bagana
Ulawun
Decade and Dco

Published: Tue 13 Dec 2016.