EGU22-12559
https://doi.org/10.5194/egusphere-egu22-12559
EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Monitoring drought impact on vegetation with Sentinel-1

Mariette Vreugdenhil1, Isabella PFeil1, Susan Steele-Dunne2, and Wouter Dorigo1
Mariette Vreugdenhil et al.
  • 1Research group Remote Sensing, Department of Geodesy and Geo-Information, TU Wien, Vienna 1040, Austria
  • 2Department of Geoscience and Remote Sensing, Delft University of Technology, Stevinweg 1, Delft 2600 GA, The Netherlands

With the Copernicus Sentinel-1 series, for the first time high temporal and spatial resolution backscatter time series have become available. Sentinel-1 backscatter observations are sensitive to changes in water content and structural changes in vegetation and soils and provide complementary information next to optical remote sensing datasets such as Leaf Area Index. However, most studies have looked at the sensitivity of Sentinel-1 backscatter to vegetation water dynamics at very local scale. Furthermore, no specific focus has yet been on monitoring drought impact on vegetation with Sentinel-1. Here we will present results of a study over Europe which assesses the potential of Sentinel-1 to monitor drought impact on vegetation.

In this study we use the record summer drought of 2018 as a case study. This drought led to decreased yields in northwestern Europe, and to decreased GPP in for example grasslands and forests (Fu et al., 2020). We have calculated anomalies of co-, and cross-polarized backscatter, and the ratio thereof, the so-called cross-ratio (CR) of 2018 with the reference year of 2016 which had normal conditions. These anomalies were compared to anomalies calculated with Copernicus Global Land Service LAI anomalies and ESA CCI soil moisture anomalies and analyzed per land cover type. The results show very strong negative anomalies in VV, VH backscatter and CR from June to November over central and northwestern Europe, similar to those observed in LAI. However, differences in patterns can be seen between LAI and CR, especially over forest areas. Although LAI showed stronger anomalies in the Netherlands and western Germany in July, CR shows stronger anomalies in eastern Germany and Czech Republic, and especially over forests. These differences in patterns may be related to the penetration depth of microwaves, and the sensitivity to vegetation water content of the above ground biomass.

How to cite: Vreugdenhil, M., PFeil, I., Steele-Dunne, S., and Dorigo, W.: Monitoring drought impact on vegetation with Sentinel-1, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-12559, https://doi.org/10.5194/egusphere-egu22-12559, 2022.

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