Fig. 1

Paths of Typhoons Saudel (a), Molave (b), and Vamco (c) and the distribution of the sea surface wind when three typhoons passed over the mooring, respectively. The magenta pentagram is the location of the mooring, the black line with red dots is the path of the typhoon, the red circle is the typhoon's category 7 wind circle, the black arrows are the wind speed vector, and the filled colors are the wind magnitude"

Fig. 2

Time evolution of vertical profiles of near-inertial current along the zonal (a) and meridional (b) directions. The black contour lines mark velocity of 0.05 m·s−1, and the black dashed lines denote the moment when the typhoon's Category 7 wind circle first impacted the mooring"

Tab. 1

Characteristics of NIWs induced by Typhoons Saudel, Molave, and Vamco"

Fig. 3

Temporal averaged profiles of buoyancy frequency during Saudel, Molave and Vamco events from HYCOM reanalysis dataset"

Fig. 4

(a) Time series of 10 m wind speeds above the sea surface at the mooring station; (b) Time depth variations of NIKE, with the red line denoting the mixed layer depth, the black solid line representing the 10 J·m-3 NIKE, and the black dashed line representing the 4 J·m-3; (c) Vertical shear rate of near-inertial current. The shading represents the periods when Typhoons Saudel (22 October to 26 October), Molave (27 October to 05 November), and Vamvo (13 November to 23 November) passed over the mooring"

Fig. 5

Time series of depth-averaged NIKE after 4-day low-pass filtering. The shading represents the periods when Typhoons Saudel (22 October to 26 October), Molave (27 October to 05 November), and Vamvo (13 November to 23 November) passed over the mooring"

Fig. 6

Depth-averaged NIKE autocorrelation coefficients from 50 to 640 m. The grey dashed horizontal line indicates the 1/e value of NIKE"

Fig. 7

Sea level anomaly (a, b, c) and geostrophic current map (d, e, f) observed by satellite altimeters. The magenta pentagram represents the mooring station"

Fig. 8

Evolution of the difference between the clockwise and anti-clockwise components of the rotating vertical wave number spectrum. The shading represents the periods when typhoons passed over the mooring"

Fig. 9

(a), (b) and (c) are the time-averaged vertical distributions of NIKE for the first five baroclinic modes by DMD in the three typhoon events, respectively; (d), (e) and (f) are vertical distribution of NIKE, black lines represent the sum of energy of the DMD modes, and the red lines represent the observed total NIKE"

Fig. 10

Time series of depth-averaged NIKE between 50 and 640 m for each dynamical mode. The shading represents the periods when typhoons passed over the mooring"

Fig. 11

Vertical profiles and corresponding time series of the first EOF mode of the near-inertial currents (a), (b) and (c) are for the second and third EOF modes, respectively. The red and blue lines represent the zonal and meridional current, respectively. The shading represents the periods when Typhoons Saudel (22 October to 26 October), Molave (27 October to 05 November), and Vamvo (13 November to 23 November) passed over the mooring"

Fig. 12

The power spectrum of average velocity at depths ranging from 50 to 150 m for the typhoons Saudel&Molave (thick black line) and typhoon Vamco (thick gray line). The black vertical lines represent the local inertial frequency f, the diurnal tidal frequency O1, and the semidiurnal tidal frequency M2, respectively. The shaded area represents the near-inertial frequency band"

Fig. 13

Time series of effective inertial frequency feff at the mooring"