Fig. 1

Bathymetry of the region around the survey line (a) and SLA (b) during the cruise on 6th August 2001. The black line indicates the whole seismic transect during the cruise, the red line indicates the part of the transect used in this study, and the black arrows indicate the geostrophic current calculated by SLA"

Fig. 2

Seismic reflection profile (a), automatically tracked reflections (b), and tracked reflections used in this study. The profile corresponds to the red line in Fig. 1"

Fig. 3

Buoyancy frequency curve varying with depth. The vertical red line indicates the reference buoyancy frequency (3.0cph), and the vertical green line indicates the average buoyancy frequency (3.9cph) in the study region, cph is the abbreviation of cycles per hour, 1cph=(1/3600)s"

Fig. 4

The average horizontal slope spectra. A total of 916 slope spectra are used to calculate average slope spectra, and error bars represent 95% bootstrap confidence interval. The internal wave interval is within the two vertical dashed lines, and the turbulence interval is within the two vertical solid lines. The slopes of two tilted lines are 1/3 and -1/2, respectively, which are used for fitting the slope spectra of turbulence and internal wave intervals"

Fig. 5

Two typical slope spectra. Error bars represent 95% bootstrap confidence intervals. The meaning of vertical dashed lines and vertical solid lines are explained in Fig.4. The slopes of internal wave interval and turbulence interval are -1/2 and 1/3, respectively (as shown by red lines)"

Fig. 6

Calculated dissipation rate (a) and diffusivity (b) by turbulence interval. The rectangle marks the strong mixing area"

Fig. 7

Calculated dissipation rate (a) and diffusivity (b) by internal wave interval. The rectangle marks the strong mixing area"

Fig. 8

Current velocity with different depths (a) and current profile (b) of the line at 6:00 am on 6th August 2001, both from the HYCOM"