Sub-seasonal extreme rainfall prediction in the Kelani River basin of Sri Lanka by using self-organizing map classification

Sub-seasonal extreme rainfall prediction in the Kelani River basin of Sri Lanka by using self-organizing map classification.

By J. F. Vuillaume, S. Dorji, A. Komolafe and S. Herath

  • Online availability of multi-model and ensemble sub-seasonal forecasts has sparked interest in extreme rainfall prediction and early warning systems.
  • Developing tropical countries like Sri Lanka face complex meteorological challenges and need effective early warning systems for flood mitigation.
  • This study examines the potential benefits of the Sub-seasonal to Seasonal (s2s) database, offered by a consortium of weather forecasting institutes, using self-organizing map classification.
  • Key findings of the study include:
    1. Establishing a connection between teleconnection indexes like the Madden–Julian Oscillation and spatiotemporal rainfall patterns.
    2. Demonstrating that the frequency of heavy rainfall events is influenced by the cluster type.
    3. Observing varying performance of s2s forecasts across different clusters.
    4. Introducing corrective bias coefficients for forecasting water volume in the basin for each cluster.
  • The study emphasizes the value of s2s forecasts for extreme rainfall prediction and advocates for the real-time release of s2s data, particularly beneficial for early warning systems in developing countries like Sri Lanka.
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