DCT-PLS Gap Filling and DMD Analysis of the Coastal Ocean Surface Current in the Gulf of Thailand

摘要

The ocean currents are one of the main driving forces for many vital coastal processes. Analyzing ocean current data, especially in coastal areas, can benefit the coastal ocean communities in deriving insight and knowledge on coastal ocean processes and variability. high frequency surface wave radars (HFSWRs) provide comprehensive and long range (30-100 km) observations of sea surface currents with high temporal (typically 0.25-1 hour) and spatial (typically 1-3 km) resolution. The data gathered from HFSWRs can therefore be well used to study eddy dynamics as well as variability in coastal ocean currents. However, high frequency surface wave radar (HFSWRs) are shore based remote sensing systems, and can be prone to environmental interferences resulting in observation failure. To this end, we first apply the Discrete Cosine Transform (DCT-PLS) algorithm to fill gaps in high frequency surface wave radar (HFSWR) data in the Gulf of Thailand from the Geo-Informatics and Space Technology Development Agency (GISTDA), Thailand. The DCT-PLS algorithm uses both time and space information to predict missing values. Finally, we also analyze and reveal dynamics of the coastal ocean circulation via dynamic mode decomposition (DMD) together with sparsity-promoting variant (SPV) approach in order to obtain insight into the dynamics and spatial structures of the ocean currents in the Gulf of Thailand. A comparison with EOF technique is also provided.