Period: 1999 – 2016
Sensor: SPOT-VGT and PROBA-V
Frequency: Yearly
Resolutions: 1km
Extent: Europe
To access data please contact: k.bornez@creaf.uab.cat
Algorithm description: The product comprises of following information – Start, End and Length of the growing season.
Unlike usually done in studies (based on vegetation indices like NDVI), here time series of leaf area index (LAI), fraction of absorbed photosynthetically active radiation (FAPAR) and fraction of vegetation cover (FCOVER) were used as inputs. In order to evaluate phenology, time series were processed using software package called Spirits. It has been developed by VITO’s remote sensing unit on behalf of the European Commission’s Joint Research Centre (EC-JRC) and it allows estimation of phenological variables (start, end, length). Four types of filters have been suggested under Spirit processing software to reduce noisy data
Accuracy: Comparison with ground measurements for birch and beech showed RMSE of ~9 days and ~16 days for start date and a RMSE of ~15 days and ~60 days for end date, respectively. Values of R2 lower than 0.21 were obtained in all the cases.
Limitations:
- Validation has been done only for two species so far.
- Overall lower accuracy.
Reference:
Bornez, K., Verger, A., Filella, I. & Penuelas, J. Land surface phenology from Copernicus Global Land time series. in 2017 9th International Workshop on the Analysis of Multitemporal Remote Sensing Images (MultiTemp) 1–4 (IEEE, 2017). doi:10.1109/Multi-Temp.2017.8035262