Asymmetric Wave Distributions of Tropical Cyclones Based on CFOSAT Observations

Abstract

Tropical cyclones (TCs) are intense low-pressure sources with strong wind forces that cause complex upper ocean conditions such as disastrous ocean waves (Monserrat et al., 2006). There are approximately 80 TCs globally every year, and about two-thirds of these TCs reach the severe scale (McBride, 1995). The waves induced by TC have severe impacts on coastal projects, maritime navigation, and other marine economy industries. Therefore, it is vital to investigate the ocean wave characteristics during TCs. A TC is characterized by cyclonic atmospheric circulation with counterclockwise (clockwise) rotation in the Northern (Southern) Hemisphere, and the motion is controlled by the large environmental flow and β-effect

Wave Field Properties in Tropical Cyclones From the Spectral Observation of the CFOSAT/SWIM Spaceborne Instrument

“…This conclusion was also proposed by Young (1998, 2017), although Shi et al. (2021) found that the asymmetric behavior of the significant wave height mainly depends on the TC intensity. In order to better characterize the wave field behavior under TC conditions, Kudryavtsev et al.…”

“…The analysis of the SWIM data performed by separating the TCs in different classes according to their relative speed allows us to highlight that the wave field is different from one class to another. According to our results, we find as in Young (2006) or Shi et al (2021) that Hs is higher on the right front quadrant of the TCs, but this is true only in situation of moderate speed TCs. In case of slow-moving TCs, the highest Hs are observed in the left front quadrant, whereas in fast-moving TCs the highest Hs are observed in the right rear quadrant.…”

“…Moon et al (2003), who analyze the wave field of TC Bonnie at two different stages, suggest that the hurricane-generated wave field is influenced not only by the radius of maximum wind but also by the TC displacement velocity. This conclusion was also proposed by Young (1998Young ( , 2017, although Shi et al (2021) found that the asymmetric behavior of the significant wave height mainly depends on the TC intensity. In order to better characterize the wave field behavior under TC conditions, Kudryavtsev et al (2015) proposed a simplified model, parameterized in terms of maximum wind and displacement speed, which explains this significant wave height asymmetry even in absence of wind field asymmetry.…”

“…These complex wind fields generate wave fields with even more complex structures. The wave field characteristic most often cited in the literature is the significant wave height ( Hs ) asymmetry characterized by the presence of the highest waves on the right side of the TCs (Kudryavtsev et al., 2015; Shi et al., 2021; Young, 2006). This feature is explained by the concept of “extended fetch” for waves which travel in the same direction as the cyclone (Young, 1998) or by the “trapped waves” concept related to a resonance phenomenon (Bowyer & MacAfee, 2005) that occurs when the wind‐generated waves cannot escape from the cyclone area because their group velocity remains of the order of the displacement velocity of the system.…”

CFOSAT: Latest Improvements in the Swim Products and Contributions in Oceanography

“…The high performances of SWIM data not only open the field to improvements in the ocean surface characterization and modeling, but also to new perspectives in the coastal and sea ice areas. After 3 years in orbit, the exploitation of SWIM data has shown its advanced capacities to provide SWH and wind at a 5 Hz sampling along-track for coastal applications, sea ice detection and characterization through the analysis of 0 [7], wave field studies in the marginal ice zone and in extreme events [15] or global estimation of additional wave-related parameters (like e.g. the Stokes drift).…”