Wind-Wave Relationship Model and Analysis of Typhoon Wave Fields in the South China Sea From HY-2A Satellite Observations

Abstract

Significant wave height is an important parameter for characterizing ocean surface waves. With the development of remote sensing technology, satellite radar altimetry has become an essential tool for obtaining significant wave height estimations. However, its measurement only covers the satellite track on the ground and cannot be applied to large regions or areas. In this study, we obtained significant wave height from the Hai Yang-2A (HY-2A) radar altimeter and sea surface wind speed at a 10-m height from the HY-2A microwave scatterometer for October 2013, and then proposed a wind-wave relationship model for the South China Sea using linear/nonlinear regression analysis at high/low wind speeds (0 to 40 m s-1). By comparison with two other windwave models and validation with HY-2A observations in November 2013, our results show that the proposed wind-wave relationship model is credible, and at low wind speed exhibited good consistency with the wind-wave model from in-situ observations. According to the proposed model, significant wave height from the HY-2A microwave scatterometer-retrieved wind speed and ocean wind wave analysis during the "1329" Typhoon Krosa were successfully obtained and determined. Data coverage of the computed significant wave height was far wider than that of the satellite radar altimeter observations and demonstrated development of typhoon wave fields over a large region. Overall, this study and proposed model provide useful information for the analysis and forecast of typhoon waves and potential storm surge disasters.

Relationships Between the Typhoon‐Induced Wind and Waves in the Northern South China Sea

“…Besides, as Hao et al. (2020) focus on the general wind‐wave relation in the SCS, observations during high‐wind conditions ( >16 m/s) are limited ( n = 37, comparing to n = 132 in this research). By screening out the mixed wind sea data set identified above, Equation overpredicts of wind seas, with RMSE of 0.71 m and MBD of 4.46%, while Equation still underpredicts the observed values (RMSE = 0.69 m and MBD = −4.24%).…”

“…A recent study for the wind‐wave model in the SCS illustrated a linearly increasing with under high‐wind forcing ( > 16 m/s; Equation ) (Hao et al., 2020). …”

“…A recent study for the wind-wave model in the SCS illustrated a linearly increasing s H with 10 U under high-wind forcing ( 10 U > 16 m/s; Equation 1) (Hao et al, 2020 H growth rate with extremely strong wind forcing, that is, the wind seas forced by high winds would approach energy saturation status.…”

“…Recently, Hao et al. (2020) proposed a wind‐wave model in SCS, suggesting that increases with nonlinearly/linearly at low/high‐wind speed conditions, respectively. Considering on continental shelves could not increase infinitely with in nature due to the energy loss (i.e., wave breaking) and saturation (Komen et al., 1984; Takagaki et al., 2016), the relationship between and in northern SCS under typhoon forcing needs further justifications.…”

An Empirical Wind‐Wave Model for Hurricane‐Forced Wind Waves in the Caribbean Sea

“…This relationship was found by Niu and Feng (2021) (hereafter NF21) to be valid even for South China Sea (SCS) typhoons that possessed different dynamical properties (e.g., translation speed, magnitude, and track). Those authors improved upon a wind-wave empirical model built by Hao et al (2020) that used satellite rather than buoy data. These representations, however, are generally only valid under wind-sea conditions and the literature is replete with examples of deviations from expectations due to the influence of swell and even wave-current interactions.…”