Abstract 152

Abstract ID: 152

Using monthly forecast of extreme events in the southwest Indian Ocean for disaster risk management: co-creation of a decision support tool for tropical cyclone risk anticipation

Lead Author: Hélène Veremes
Laboratoire de l’Atmosphère et des Cyclones (LACy), CNRS, Université de La Réunion, Météo-France, La Réunion, France

Keywords: tropical cyclones, southwest Indian Ocean, decision support tool, co-production

Abstract: The PISSARO project deals with the application of weather and ocean forecasts on a subseasonal scale for disaster risk management in the southwest Indian Ocean. Within the framework of this project, discussions have been established between scientific, operational experts in subseasonal forecasting and potential users in order to provide them with adapted forecasting products. The collaborative work carried out by the scientists from the LACy, the forecasters from the DIROI and the humanitarian stakeholders from the PIROI has thus enabled the development of tools and products to anticipate the cyclone hazard and heavy rainfall in the southwest Indian Ocean region and to support the tropical cyclone disaster risk management (DRM).
The PIROI runs a large risk management programme in the southwest Indian Ocean. Until recently, the weather forecasting data provided to them did not cover all the needs of the Ready-Set-Go concept and thus limited their anticipatory actions. In order to provide them with a seamless forecast, a user-oriented cartographic product has been developed. The inhabited lands of the southwest Indian Ocean have been divided into several zones. Each zone is assigned a weight between 1 and 8 which takes into account: the level of probability of the occurrence of a storm or tropical cyclone within a 300 km radius, the level of false alarms and associated good detections and the recurrence of a signal over the previous two runs. The PIROI has listed potential actions for each weight. These actions can be separated into three types: enhanced watch, warning and preparedness actions. Information is given on a weekly basis. Each run produces 3 decision support maps for each of the next 3 weeks.
The PIROI is testing this product under operational conditions for the 2022-2023 cyclone season in the southwest Indian Ocean basin. Each week, these automatically produced decision support maps are sent to the disaster preparedness and response team. Following this communication, expert advice from forecasters can be required in the event that strong actions are suggested by the automatic product. This close collaboration facilitates the appropriation of the product by the users, allows for a real-time feedback between developers and users and may possibly lead to some adjustments of the product during the season.
At the end of the cyclone season, a debriefing will be organised to assess the contribution of the monthly forecasts for DRM, to co-evaluate the performance of this product and to propose improvement paths. We will present the results of this experimentation.

Sylvie MALARDEL (Laboratoire de l’Atmosphère et des Cyclones (LACy), UMR8105, CNRS, Université de La Réunion, Météo-France, La Réunion, France)
François BONNARDOT (Direction InterRégionale de Météo-France dans l’Océan Indien (DIROI), Météo-France, La Réunion, France)
Camille BLANC (Plateforme d’Intervention Régionale de la Croix-Rouge dans l’Océan Indien (PIROI), La Réunion, France)