Monitoring the Spatio-Temporal Dynamics and Recovery of Floating Raft Aquaculture Post-Typhoon Yagi Using Sentinel-1 Time-Series Data: A Case Study in Hai Phong

Abstract Rapid assessment of typhoon damage to coastal aquaculture is critical for effective risk management. This study utilizes multi-temporal Sentinel-1 SAR data to monitor the spatio-temporal dynamics and recovery of Floating Raft Aquaculture (FRA) in Hai Phong, Vietnam, following Typhoon Yagi. SAR’s all-weather operational capability allows for the quantification of FRA area changes through radar backscatter analysis. The findings reveal that Typhoon Yagi caused an immediate loss of 1,365 ha of Floating Raft Aquaculture (FRA). Monitoring showed the area dropped to a minimum of 6.35 ha in October 2024 before exhibiting a steady recovery trend. By June 2025, the infrastructure reached 939.82 ha, representing an approx. 69% restoration of the initial pre-typhoon area within a 9–10 month period. The classification results demonstrated high reliability, with an Overall Accuracy of 89.7% and a Kappa coefficient of 0.86. User’s and Producer’s accuracies for the FRA class were 91.2% and 87.5%, respectively. This research demonstrates SAR remote sensing’s capacity to provide timely, accurate information across the full disaster management cycle—from rapid assessment to long-term recovery monitoring. Such data supports functional agencies in implementing effective response and sustainable management strategies for the aquaculture sector amidst increasingly complex natural disasters.