In the HARVEST project we are managing all aspects of the collection of citizen reports through the RMI smartphone app.

The project HARVEST required development work in four components:

1. the concept, design, wireframe and prototype of the reporting feature;
2. the actual coding (outsourced) of the feature in the app code for two platforms (iOS and Android);
3. realisation of a back-end to capture the citizen reports and add it to a structured database;
4. development of a dedicated internal viewer and adaptation of the WOW-BE portal to visualise the citizen reports both internally and publicly.

The quality control currently includes two different strategies.

• Sanity check: each incoming observation is subject to a sanity or plausibility check. The sanity check consists of a real-time comparison with the relevant field of our nowcasting system INCA-BE. The thresholding limits to attach a quality-label to an observation were set in consultation with our forecasters.
• User reputation score: for each user, a mean plausibility score of all his observations is retained, giving in an overall reputation score of that particular user. This profiling is done within the limits of the General Data Protection Regulation (GDPR). The HARVEST data set can be filtered by using that reputation score.

The HARVEST project is a permanent project within the RMI, and further refinement of the existing elements as well as the addition of new elements are envisaged. We are investigating several options for this development:

• Addition of pictures: users will be able to send a photo along with their observation.
• Expert group: the establishment of a well-defined group of highly reliable observers, to be used for the construction of a high-quality subset within the vast HARVEST dataset.

Similar initiatives exist at other national weather services, e.g. at Météo-France (France), DWD (Germany), FMI (Finland) and MeteoSwiss (Switzerland). A working group on this topic has been established under the umbrella of the EUMETNET, the European network of national weather services. Bilateral exchanges are envisaged with our neighbouring countries to extend the effective range of the HARVEST initiative.