Investigating ocean surface responses to typhoons using reconstructed satellite data

Abstract

Due to the cloud blocking, the research on the responses of upper ocean to typhoons using satellite data is greatly affected. At present, most of the solutions are based on lower time resolution data or composite satellite data. In this paper, multi-source satellite data were fused by weighted average method and reconstructed through the Data INterpolating Convolutional Auto-Encoder method (DINCAE) and used to investigate daily sea surface responses to typhoons. The root mean squared error (RMSE) between the reconstructed data and the cross-validation data for SST and CHL was only 1.093 °C and 0.7833 mg/m3. Three response patterns were reported over the East China Sea (ECS). The first one was that both SST and CHL have significant changes, the second was that only SST changes a lot, and the third one was only CHL changes significantly after typhoons. Moreover, it was found that, after some typhoons, the SST or CHL had a wide range of changes, but the amount of changes is not large. The different responses were related to the wind speed and moving speed of typhoons. In addition, when two typhoons pass by successively, although the wind speed is low, the sea surface would have significant responses. Further, areas of significant SST drops coincide with negative sea level anomaly (SLA) fields in some typhoon tracks. SST drops to its minimum level 2 days after the arrival of a typhoon and returns to its previous level 15 days after the arrival. CHL keeps increasing until 4 days after the typhoon’s passage, and then drops to its initial level around 10 days after the passage. The responses of SST and CHL decrease with distance, with prominent changes occurring within 100 km of the typhoon’s center.

Keywords

• Sea surface response
• Typhoons
• SST
• Chlorophyll concentrations
• Satellite data