Field: Climate change monitoring, Natural disaster management
Global Technical function: Collecting, Geomatic monitoring, Sensing


Volcanic gas emissions, together with geology related data such as seismic activity, are important indicators in the volcanic risk assessment procedure for natural disaster management. In the project Network for Observation of Volcanic and Atmospheric Change – NOVAC, a global metrology network of stations for measurements of gas emissions and air pollution monitoring from volcanoes was established.

The core of the project was to install sensing equipment on active volcanoes worldwide, and implement their capability of quantitative gas flux measurement in the risk assessment routines at respective volcano. The remote automatic sensor system measure the gas flux and submits this information in real-time to an observatory. The main application was to provide new parameters for the observatories for performing risk assessments, gas emission estimations and geophysical research on a local scale. The gathered data can also, apart from being directly applied in the geomatic monitoring of a specific volcano, be applied in validations of satellite instruments for observing volcanic gas emissions. Such validations have previously not been possible due to lack of data. Further, on a global scale, the installed instruments can be used for research concerning global volcanic gas emission estimates, correlations between volcanic activity on different geographical locations, climate change monitoring, and studies of stratospheric ozone depletion.

Active volcanoes are often located in remote areas lacking infrastructure such as electricity and telecommunication. The climate conditions can be severe due to the exposed position, and the surroundings of active volcanoes may be strongly affected by aggressive gases, acid rain and fine ash depositing. The gas emission measuring equipment must therefore be reliable, robust and self-sufficient, but still be able to measure in real-time and to submit data to the observatory.

The instrument used in the project is based on differential optical absorption spectroscopy (DOAS), and is capable of real-time and unattended measurements of emission fluxes of SO2 and BrO. A first version of the instrument was developed in the EC funded project Development of optical remote sensing instruments for volcanological applications – DORSIVA, which was funded under FP5. In order to cope with the severe conditions and to able to transmit data, the instrument has been further developed. Measurement strategies and software routines has been introduced in order to perform the gas flux measurements of the various volcanoes.

The measurement of gas emissions from a specific volcano was assessed by installing instruments in the area surrounding the volcano. By collecting scattered sunlight and scanning the sky over 180 degrees from horizon to horizon from a location downwind the volcano, and by taking wind speed into account, the flux can be estimated.

The project was supported by the European Commission Sixth Framework Programme (FP6), a grant funding programme,, and was completed in 2009. Seventeen partners from the following countries throughout the world participated in the project: Sweden (coordinator), Germany, Belgium, UK, France, Italy, Mexico, Nicaragua, Costa Rica, Colombia, El Salvador, DR Congo, USA, Ecuador, and Guatemala. Instruments were initially installed on nineteen volcanoes from four continents, including some of the most active and strongest degassing volcanoes in the world.

The instruments and the measuring strategy have been used in a variety of conditions worldwide. The Technology Readiness Level is therefore 9 on the TRL scale.