The Earth programme covers SRON’s activities for Earth system science. Observing the earth from space has a big advantage as compared to ground-based observations. It provides time series of measurements with global and homogeneous coverage. This has led to initiatives for international space research programmes in which earth observation provides essential diagnostic tools for improving our understanding of planet earth. SRON's Earth programme focuses on atmospheric measurements of (greenhouse) gas abundances and aerosols, and the interpretation of the data in terms of processes fundamental for climate and air quality. The activities cover contributions to the full project cycle of space-borne earth observation: the development of critical and/or enabling technologies and subsystems for the instruments, scientific support to the industrial instrument development, calibration, retrieval of the data products from the measurements and the scientific exploitation of the data products using atmospheric models and inversions. The aim is to improve our understanding of planet earth and the challenges we are faced with today, like climate change and air quality
SRON was responsible for the development and production of the detector modules of the SCIAMACHY instrument on-board ESA's Envisat satellite (end of operations April 2012), the in-flight calibration and retrieval of trace gases, in particular the carbon-cycle gases CO and CH4 in the SWIR spectral region. For ESA's Sentinel-5 Precursor mission (launch foreseen early 2016) with the TROPOMI instrument as single payload, SRON has developed the immersed grating and front-end read-out electronics of the Short-Wave Infra Red (SWIR) module. SRON is scientifically responsible for the SWIR module and the delivery of its EU GMES data products CO and CH4. With their accurate measurements down to the Earth's surface these instruments allow for research into the lowest parts of the atmosphere, where both human-induced and natural emissions take place. SRON's retrieval and inverse modelling activities using data form the SWIR channels of SCIAMACHY, the Japanese GOSAT and the future Sentinel-5 (Precursor) yield new insights in the distribution of sources and sinks of CO, CO2 and CH4.
An upcoming research area in our group is the role of aerosols on climate and air quality. In the latest (2013) assessment report report of the IPCC (Intergovernmental Panel for Climate Change) aerosols remain to represent one of the most important limiting factors in our ability to quantify present day radiative forcing, the uncertainty on the aerosol radiative forcing being as large as the total radiative forcing by CO2. As for climate research also in the field of air quality research it is of crucial importance to be able to discriminate between various aerosol types, e.g. aerosol of anthropogenic origin versus natural origin and between various sizes of particulate matter.
Under SRON scientific lead the novel SPEX2Earth instrument is being developed by a Dutch consortium of industry, institutes and academia. SPEX2Earth is a multi-angle spectrapolarimeter designed for a polarimetric accuracy that is an order of magnitude better than current and planned polarimetric instruments. This improved accuracy is needed to quantify the essential aerosol properties (optical thickness, absorption, size and type) with the accuracy needed to significantly advance our knowledge on the role of aerosols in climate change and air quality. The scientific activities focus on the retrieval of aerosol properties from multi-angle spectropolarimetry and deducing their impact on radiative forcing.
 TROPOMI is a collaboration of Dutch Space, KNMI, SRON, and TNO commissioned by the NSO and ESA. Dutch Space is prime contractor for the development of the instrument. The scientific management is in the hands of the KNMI and SRON. TROPOMI is funded by the Ministry of Economic Affairs, the Ministry of Education, Culture and Science, and the Ministry of Infrastructure and Environment.