The WorldWater Round Robin has been concluded

We are pleased to announce that the outcome of the WorldWater Round Robin has now been concluded and the results published in Remote Sensing – a peer-reviewed, open access journal about the science and application of remote sensing technology.

The Round Robin study was motivated by a wish to advance the field of EO based surface water detection by providing a systematic review and evaluation of algorithms for surface water extent mapping and monitoring. The study was especially looking for evidence that could demonstrate the improved observation capacity offered by the latest generation of open and free satellite data from the Sentinel-1 and -2 missions. These data come with improved spatial detail and with multi-sensor observation capacity and therefore has the potential to take space-based surface water monitoring to the next level especially when compared to existing global benchmark products.

Water occurrence as mapped from optical Landsat imagery in 30-meter resolution (left) compared to the water occurrence mapped from the combined use of Sentinel-1 and Sentinel-2 in 10-meter resolution (right).

As reported previously the Round Robin exercise generated interest from all over the world and all 15 contributions were compared over 5 test sites and using the same set of validation samples. The results indicate that, while using a single sensor approach (applying either optical or radar satellite data) can provide comprehensive results for individual sites and time periods, then a dual sensor approach (combining data from both optical and radar satellites) is the most effective way to undertake large scale national and regional surface water mapping across bioclimatic gradients.

While it may sound trivial that a dual sensor approach is better than a single sensor approaches the results does underpin the efforts by the WorldWater team in their continued collaboration with countries on adopting best-practices for implementing national satellite-based surface water monitoring systems.

The full study of the Round Robin exercise can be read here and the validation data samples has also been published at Zenodo.