Coastal Waveform Retracking in the Slick-Rich Sulawesi Sea of Indonesia, Based on Variable Footprint Size with Homogeneous Sea Surface Roughness

Waveforms of radar altimeters are often corrupted due to heterogeneous sea surface roughness within footprints, such as slicks. In past studies, subwaveform retrackers such as the adaptive leading edge subwaveform retracker (ALES) which use only a section of the waveform have been proposed. However, it is difficult to choose a reasonable estimation window from an individual waveform. In the present study, a post-processed subwaveform retracker is proposed which identifies the waveforms of surrounding along-track points. The size of the estimation window is variable and is determined to keep the sea surface roughness within the corresponding footprint homogeneous. The method was applied to seven years of 20 Hz Jason-2 altimeter data over the slick-rich Sulawesi Sea of Indonesia and compared with ALES and sensor geophysical data record (SGDR) products. The standard deviation of the sea surface dynamic heights was around 0.13 m, even without spatial smoothing or some geophysical corrections. This is only 75% and 25% of the ALES and SGDR results, respectively. Moreover, all retrievals of the range, SWH, and sigma0 include less outliers than the other products. These results indicate that the variable estimation windows determined in the present study can adapt well to the variation of sea surface roughness.

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A Novel Sea Surface Roughness Parameterization Based on Wave State and Sea Foam

Journal of Marine Science and Engineering ◽

10.3390/jmse9030246 ◽

2021 ◽

Vol 9 (3) ◽

pp. 246

Author(s):

Difu Sun ◽

Junqiang Song ◽

Xiaoyong Li ◽

Kaijun Ren ◽

Hongze Leng

Keyword(s):

Surface Roughness ◽

Wind Speed ◽

Drag Coefficient ◽

Sea Surface ◽

High Wind Speed ◽

Wave State ◽

Wind Speeds ◽

Sea Surface Roughness ◽

Extreme Wind ◽

The Impact

A wave state related sea surface roughness parameterization scheme that takes into account the impact of sea foam is proposed in this study. Using eight observational datasets, the performances of two most widely used wave state related parameterizations are examined under various wave conditions. Based on the different performances of two wave state related parameterizations under different wave state, and by introducing the effect of sea foam, a new sea surface roughness parameterization suitable for low to extreme wind conditions is proposed. The behaviors of drag coefficient predicted by the proposed parameterization match the field and laboratory measurements well. It is shown that the drag coefficient increases with the increasing wind speed under low and moderate wind speed conditions, and then decreases with increasing wind speed, due to the effect of sea foam under high wind speed conditions. The maximum values of the drag coefficient are reached when the 10 m wind speeds are in the range of 30–35 m/s.

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Influence of sea surface roughness on the electromagnetic wave propagation in the duct environment

2010 Second IITA International Conference on Geoscience and Remote Sensing ◽

10.1109/iita-grs.2010.5602649 ◽

2010 ◽

Cited By ~ 8

Author(s):

Xiaofeng Zhao ◽

Sixun Huang ◽

Hongjun Fan

Keyword(s):

Surface Roughness ◽

Wave Propagation ◽

Electromagnetic Wave ◽

Electromagnetic Wave Propagation ◽

Sea Surface ◽

Sea Surface Roughness

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Impact of Sea Spray and Sea Surface Roughness on the Upper Ocean Response to Super Typhoon Haitang (2005)

Journal of Physical Oceanography ◽

10.1175/jpo-d-20-0208.1 ◽

2021 ◽

Author(s):

Lianxin Zhang ◽

Xuefeng Zhang ◽

William Perrie ◽

Changlong Guan ◽

Bo Dan ◽

...

Keyword(s):

Surface Roughness ◽

Ocean Waves ◽

Sea Surface ◽

Sea Spray ◽

Upper Ocean ◽

Surface Cooling ◽

Super Typhoon ◽

Sea Surface Roughness ◽

Momentum Fluxes ◽

The Right

AbstractA coupled ocean-wave-sea spray model system is used to investigate the impacts of sea spray and sea surface roughness on the response of the upper ocean to the passage of the super typhoon Haitang. Sea spray mediated heat and momentum fluxes are derived from an improved version of Fairall’s heat fluxes formulation (Zhang et al., 2017) and Andreas’s sea spray-mediated momentum flux models. For winds ranging from low to extremely high speeds, a new parameterization scheme for the sea surface roughness is developed, in which the effects of wave state and sea spray are introduced. In this formulation, the drag coefficient has minimal values over the right quadrant of the typhoon track, along which the typhoon-generated waves are longer, smoother, and older, compared to other quadrants. Using traditional interfacial air-sea turbulent (sensible, latent, and momentum) fluxes, the sea surface cooling response to typhoon Haitang is overestimated by 1 °C, which can be compensated by the effects of sea spray and ocean waves on the right side of the storm. Inclusion of sea spray-mediated turbulent fluxes and sea surface roughness, modulated by ocean waves, gives enhanced cooling along the left edges of the cooling area by 0.2 °C, consistent with the upper ocean temperature observations.

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