Identifying and interpreting extreme rainfall events using image classification

Abstract

This study presents the first attempt to identify extreme rainfall events based on surrounding sea-level pressure anomalies, using neural network-based classification. Sensitivity analysis was also performed to identify the spatial importance of sea-level pressure anomalies. Three classification models were generated: the first classifies the patterns between extreme and regular rainfall events in the North West of England, the second classifies the patterns between extreme and regular rainfall events in the South East of England, and the third classifies between the patterns of extreme events in the North West and South East of England. All classifiers obtain accuracies between 60 and 65%, with precision and recall metrics showing that extreme events are easier to identify than regular events. Finally, a sensitivity analysis is performed to identify the spatial importance of the patterns across the North Atlantic, highlighting that for all three classifiers the local anomaly sea-level pressure patterns around the British Isles are key to determining the difference between extreme and regular rainfall events. In contrast, the pattern across the mid and western North Atlantic shows no contribution to the overall classifications. HIGHLIGHTS Neural networks can distinguish between extreme and regular rainfall events.; The sea-level pressure surrounding the UK is key to distinguishing extreme events.; The western North Atlantic does not contribute to classifying extreme events.;

Keywords

• classification
• extreme events
• image classification
• rainfall extremes
• sea-level pressure