A distributed time-lapse camera network on high-arctic Svalbard to track vegetation phenology with high temporal detail and at varying scales 

Abstract

<p>Near-surface remote sensing techniques are essential monitoring tools to provide spatial and temporal resolutions beyond the capabilities of orbital methods. This high level of detail is especially helpful to monitor specific plant communities and to accurately time the phenological stages of vegetation – which satellites can miss by days or weeks in frequently clouded areas such as the Arctic. Therefore, we established a measurement network that is distributed across varying plant communities in the high arctic valley of Adventdalen on the Svalbard archipelago, with the aim to monitor vegetation phenology. The network consists of ten racks equipped with sensors that measure NDVI (Normalized Difference Vegetation Index), soil temperature and moisture, as well as time-lapse RGB cameras. Three additional time-lapse cameras are placed on nearby mountain tops to provide an overview of the valley. From these RGB photos we derived the vegetation index GCC (Green Chromatic Channel), which has similar applications as NDVI but at a fraction of the cost of NDVI imaging sensors. To create a robust timeseries for GCC, each set of photos was adjusted for unwanted movement of the camera with a stabilizing algorithm that enhances the spatial precision of these measurements. We show how this data can be used to monitor different vegetation communities in the landscape and that this can form the basis for a direct comparison to space-borne observations and further upscaling.</p>