Present paper studies the ocean response to super-typhoon Haiyan based on satellite and Argo float data. First, we show the satellite-based surface wind and sea surface temperature during super-typhoon Haiyan, and evaluate the widely-used atmospheric and oceanic analysis-or-reanalysis datasets. Second, we investigate the signals of Argo float, and find the daily-sampling Argo floats capture the phenomena of both vertical-mixing-induced mixed-layer extension and nonlocal subsurface upwelling. Accordingly, the comparisons between Argo float and ocean reanalysis reveal that, the typhoon-induced upwelling in the ocean reanalysis needs to be further improved, meanwhile, the salinity profiles prior to typhoon arrival are significantly biased.

The Bragg resonance (BR) of a reflection coefficient resulting from the propagation of monochronic waves over periodically submerged breakwater was studied using the non-hydrostatic numerical model SWASH (Simulating WAves till SHore). Bragg resonance occurs when the incident wavelength is approximately twice the structural length of a periodic structural breakwater according to Bragg’s law and conditions. This study aimed to investigate the dynamics of Bragg resonance at water depths of 0.2, 0.3, and 0.4 m as the number of periodically submerged breakwater and their wavelengths changed. Specifically, this study focused on the Bragg resonance point of occurrence at a ratio of two structural wavelengths to the incoming wavelengths (2S/L). Regular waves were propagated over two periodically submerged breakwaters, with increasing structural wavelengths from 1 to 2 m at 0.2 m intervals. The results showed that Bragg resonances rapidly increase in value as the water depth decreases, but do not shift in their point of occurrence as the number of periodically submerged breakwaters increases. However, the Bragg resonance shifts leftward in $2S/L$ as the structural wavelength increases, with a slight increase in value at shallower water depths. More incident wave energy is reflected when the number of periodically submerged breakwater increases compared with when the structural wavelength of the periodically submerged breakwater increases. The differences in the Bragg resonance values are associated with the changes in the number of periodically submerged breakwater. Additionally, the shift in the point of occurrence was influenced by both water depth and structural length. This causes the Resulted Bragg resonance to deviate from the Expected Bragg resonance, which could be the reason why Bragg resonance does not mainly occur at $2S/L=1$, as stated by Bragg’s law.

Tropical cyclones (TCs) are modulated by El Niño-Southern Oscillation (ENSO) on interannual timescales as ENSO impacts local Sea Surface Temperatures (SST) and atmospheric conditions, especially in the Pacific basin. The frequency, intensity, startup SST, windshear and life cycle of TCs vary between ENSO phases and TC seasons. Previous research focused on the Southwest Pacific (SWP) Basin has consistently shown that during El Niño phases TCs tend to form more towards the central Pacific, while during La Niña, their formation shifts towards the northeast coast of Australia. Also, TCs form more frequently during the late TC seasons than during the early TC seasons. Here, TC genesis is assessed using a Coupled ENSO index (using Niño 3.4 SST and the Southern Oscillation Index (SOI)) and a grouping into early (Oct-Jan) and late (Feb-May) TC seasons, in the decades from 1971 to 2020. We find that though the number of TCs in SWP are decreasing over the years, their SST at genesis and maximum wind speed are increasing, generating more intense TCs over the SWP basin. TCs formed during El Niño are more intense than those formed during La Niña even though there is no significant difference in their SST at genesis. We find that the threshold of environmental factors responsible for cyclogenesis in SWP are gradually changing, leading to more severe TC events in the region.