Earth Challenge : NO₂ measurements from ultralight aircrafts

Introduction

Earth Challenge is a 27000 km expedition between Australia and Belgium, onboard 4 ultralight aircrafts, which took place in April and November 2009. The objective of the 7 pilots team, in cooperation with the World Wildlife Fund (WWF), was to draw the public's attention to the environmental problems such as sea rising, pollution and climate change. The project has been supported by BIRA-IASB. The UV-VIS DOAS group together with the mechanical workshop team, built a new remote-sensing instrument, namely the ULM-DOAS, which was installed onboard one of the aircraft. This instrument is primarily aimed to NO₂ monitoring, but other chemical species are detectable, such as formaldehyde and sulfur dioxide.

Instrument and operation The ULM-DOAS instrument is based on a compact grating spectrometer (200-750nm) controlled by a PC-104 embedded single board computer. An optical fiber is installed under the wing of the plane and transmits the diffuse sky-light to the spectrometer. Measurements and spectral analysis are fully automated and a gps system is used for the georeferencing of the data.

Preliminary results

Example of NO₂ measurements achieved by the ULM-DOAS instrument during Earth Challenge. Concentrations increase from blue to red.

Ship cemetery of Chittagong (Bengladesh)

The Po Valley (Italy)

Below, a tropospheric NO₂ map obtained by averaging the data from the satellite instrument GOME-2 over November 2009, with the aircrafts trajectory. NO₂ polluted zones are clearly seeable above large cities (Courtesy : Jeroen van Gent)

Links

Visit also the Earth challenge web site

Contact

For more information, please contact : Alexis MERLAUD, Caroline FAYT and Michel VAN ROOZENDAEL