Techs4Times - innovative techniques for the generation and evaluation of Sentinel time series

Abstract

"With regard to global food security the modelling of plant growth and yield with high resolution satellite data is an important issue. The generation of high-resolution time series is usually hampered by reduced temporal coverage and atmospheric disturbance. The resulting variability in observation times significantly reduces the consistency of large area observations and can negatively impact on subsequent applications. The focus of the Techs4TimeS project first lies on the development of generic pre-processing and analysing methods that allow a targeted evaluation of RapidEye data sets as well as MODIS and Sentinel in order to generate time series in unprecedented temporal and spatial detail. To achieve this, prior methods for data synthesis and data fusion shall be taken up, further developed and optimized with regard to their performance. A second major goal is the concrete application of the improved seasonal time series in an exemplary scenario, which will reveal key benefits and demonstrate practicability. As an example the biophysical parameters Fraction of Absorbed Photosynthetic Active Radiation (FAPAR) and the Leaf Area Index (LAI) are derived by using statistical methods and radiative transfer modelling (RTM). The focus is set on the minimization of computation efforts for mapping extensive areas. As a study site the TERENO test site DEMMIN in Mecklenburg-Western Pomerania was selected. In collaboration with the calibration and validation facility DEMMIN (DLR) in situ data was collected in 2014. On several wheat and maize fields LAI, FAPAR, vegetation height and chlorophyll were measured each week during the vegetation period. Destructive sampling served for the calibration of the LAI and FAPAR measuring devices as well as for the RTM. Further fieldwork is planned for 2015. Based on the results a yield service will be developed, which uses a crop model that benefits from the derived FAPAR product as an input parameter."