INVESTIGATION OF SENTINEL-1 TIME SERIES FOR SENSITIVITY TO FERN VEGETATION IN AN EUROPEAN TEMPERATE FOREST

This study compares established evapotranspiration products in central Europe and evaluates their multi-seasonal performance during wet and drought phases in 2017–2020 together with important soil–plant–atmosphere drivers. Results show that SEVIRI, ERA5-land, and GLEAM perform best compared to ICOS (Integrated Carbon Observation System) measurements. During moisture-limited drought years, ET (evapotranspiration) decreases due to decreasing soil moisture and increasing vapor pressure deficit, while in other years ET is mainly controlled by VPD (vapor pressure deficit).

Ecosystem resistance reflects their susceptibility during adverse conditions and can be changed by land management. We estimate ecosystem resistance to drought and temperature globally. We find a higher resistance to drought in forests compared to croplands and an evident loss of resistance to drought when primary forests are converted to secondary forests or they are harvested. Old-growth trees tend to be more resistant in some forests and crops benefit from irrigation during drought periods.

This is a concept study of water dynamics across winter wheat starting from ground-based L-band radiometry in combination with on-site measurements of soil and atmosphere. We research the feasibility of estimating water potentials and seasonal flux rates of water (water uptake from soil and transpiration rates into the atmosphere) within the soil-plant-atmosphere system (SPAS) of a winter wheat field. The main finding is that L-band radiometry can be integrated into field-based SPAS assessment.