Sentinel satellite-based mapping of plant productivity in relation to snow duration and time of green-up

This is chapter 1 of the State of Environmental Science in Svalbard (SESS) report 2019 (https://sios-svalbard.org/SESS_Issue2). Svalbard’s climate is undergoing dramatic changes, but how this will influence plant productivity is largely unknown. Understanding these changes at the ecosystem level requires that we use data from different sources – including satellites – to assess climate-induced effects on plant vitality and productivity. However, measuring plant productivity is a challenging task. For the Adventdalen area we use radar satellite data to map snow and ice in the melting season and optical satellite data to map the start and peak of the growing season. The satellite data can be related to plant productivity, but must be interpreted based on measurements done in the field. An observation system for continuous field monitoring of vegetation was established in Adventdalen in Svalbard in 2015. This system consists of field-based racks with various sensors and cameras, which are placed in different vegetation types. The system has successfully recorded the timings of green-up, plant growth and senescence since its establishment. To further increase the usefulness of the observation system, we need to develop methods to validate the satellite data with data from the sensors and cameras on the racks in Adventdalen. This would allow more accurate estimates of plant productivity over broader regions and scaling up to all of Svalbard. The most advanced instrument in this observation system is a state-of-the-art spectrometer that measures radiances and sun-induced fluorescence; it was deployed in Adventdalen in the summer of 2019. This expensive instrument can give even better estimates of plant productivity and can also be used to calibrate the other measurements and the satellite data. However, the observation system as currently configured in Adventdalen does not provide sufficient data on bryophytes (mosses)