The Extreme Rainfall Detection System (ERDS), developed and implemented by ITHACA, is a service for the monitoring and forecasting of exceptional rainfall events, with a nearly global geographic coverage.

The Extreme Rainfall Detection System (ERDS), developed and implemented by ITHACA, is a service for the monitoring and forecasting of exceptional rainfall events, with a nearly global geographic coverage.

This system is conceived to be a strategic tool, providing complete, immediate and intuitive information about potential flood events, to be used during the preparedness and response phases of the emergency cycle.

The information is accessible through a WebGIS application, developed in a complete Open Source environment, that processes and disseminates warnings in an understandable way also for non-specialized users.

Available capabilities include the analysis of both the near real-time and the forecasted rainfall amount for different lead times, with the aim to deliver extreme rainfall alerts.

The system has been used by UN World Food Programme (WFP) Emergency Preparedness Unit. Currently, information regarding cumulated rainfall and extreme rainfall alerts are integrated in the portal developed by the TRIBUTE (TRIgger BUffers for inundaTion Events) DG ECHO funded project.

NASA Global Precipitation Measurement (GPM) data, in particular the Integrated Multi-Satellite Retrieval for GPM (IMERG) product, is used as near real-time source. GPM data have a spatial resolution equal to 0.1x0.1 lat/lon degrees, and an extent included between 60° latitude N and 60° latitude S. The temporal resolution is 30-minute.

Five different alert levels can be visualized, based on specific rainfall thresholds, defined as the amount of precipitation for a given duration (12 hr, 24 hr, 48 hr, 72 hr, 96 hr). Threshold values were calculated, for every aggregation interval, on the basis of a percentage of the mean annual precipitation (Schneider, Udo; Becker, Andreas; Finger, Peter; Meyer-Christoffer, Anja; Ziese, Markus (2015): GPCC Monitoring Product: Near Real-Time Monthly Land-Surface Precipitation from Rain-Gauges based on SYNOP and CLIMAT data. DOI: 10.5676/DWD_GPCC/MP_M_V5_100; http://dx.doi.org/10.5676/DWD_GPCC/MP_M_V5_100).

This system is also able to provide a longer lead-time alerts (up to 6 days) for heavy rain and floods, using forecast rainfall data, coming from NOAA-GFS (Global Forecast System) deterministic weather prediction models, with 0.25x0.25 lat/lon degrees resolution and worldwide coverage, updated on a 12-hour basis.