Measurements

Global Ozone Monitoring by Occulation of Stars (GOMOS)
GOMOS is a stellar occultation instrument on board the European Space Agency's Envisat Satellite. We use it to study both direct and indirect effects of solar proton events on NOx and ozone in the mesosphere and stratosphere. For more information on GOMOS, go to the GOMOS web pages.

AURA/OMI
The Dutch-Finnish Ozone Monitoring Instrument (OMI) onboard the NASA EOS Aura spacecraft is a nadir viewing spectrometer that measures solar reflected and backscattered light in a selected range of the UV and visible spectrum. Our group is responsible for the OMI UV radiation retrieval algorithm and data dissemination. Also, we take care of the OMI very fast delivery (VFD) service which provides near real time (about 15 minutes after the overpass) satellite measurements over the Northern Hemisphere. OMI SO₂ data and Aerosol Index have been used for monitoring the volcanic eruptions in Iceland, Eyjafjallajokull in 2010 and Grimsvotn in 2011. Furthermore OMI total ozone data are used in ozone hole research and climate-related applications. OMI tropospheric NO₂ concentrations have been used to monitor the emissions during the Russian forest fires and to study the ship tracks over the Baltic sea and the air quality in Helsinki. An high resolution OMI tropospheric NO2 average dataset over the Northern Europe is publicly available at this link.

OSIRIS
For more information on OSIRIS, go to the OSIRIS web pages.

Pandora
Pandora is a compact computer-controlled spectrometer system consisting of a head sensor and a small spectrometer. The head sensor is mounted on a two-axis motion controller to enable sun and sky radiance measurements. The wavelength range of the system is 270 - 530 nm with 0.5 nm steps and a field of view of 1.6 degrees. Total column products resulting from direct-sun measurements include O₃, NO₂, SO₂, H₂O, HCHO and aerosol properties with 0.1 DU uncertainty. Additionally, measurements of O₃ and NO₂ profiles are possible via sun-sky radiance scanning.