Fig. 1

ARGO buoy (red dots) and RAMA buoy (yellow stars)"

Fig. 2

Annual distribution of barrier layer thickness (BLT) in meters, based on gridded ARGO data (left) and WOD data (right)"

Fig. 3

Barrier layer thickness (BLT), isothermal layer depth (ILD), and mixed layer depth (MLD) derived from gridded ARGO data (solid curves) and RAMA data (dashed curves) at (90°E, 0°) (a, b, c) and at (90°E, 15°N) (d, e, f)"

Fig. 4

Annual distributions of isothermal layer depth (left) and mixed layer depth (right) in meters, based on gridded ARGO data"

Fig. 5

Map of barrier layer thickness standard deviation (units: m) after 7-month high-pass filtering"

Fig. 6

Power spectra for barrier layer thickness after 7-month high-pass filtering in the regions A (a) and B (b). The dash curve indicates the 95% confidence levels"

Fig. 7

The standard deviation (m) of BLT, ILD and MLD. Showing variability in the 5~7 month (a, b, c) and 2.5~4.5 month (d, e, f) bands"

Fig. 8

Depth-time sections of temperature, salinity (shaded), and time series of isothermal layer depth (black lines), mixed layer depth (black dashed lines), and barrier layer thickness. The red line indicates the barrier layer thickness in the 5~7 month band. The blue line indicates the barrier layer thickness in the 2.5~4.5 month band. Panels (a, b, c) are at (90°E, 0°); and (d, e, f) are at (90°E, 15°N)"

Fig. 9

Time series of sea level anomaly (SLA) and isothermal layer depth (ILD). Blue line indicates SLA in Region A, and black line indicates ILD in Region A. Red line indicates ILD in Region B. Panels a and b show variability in the 5~7 month band, and 2.5~4.5 month band, respectively"

Fig. 10

Lead/lag correlation between the isothermal layer depths in Region A and Region B. Solid line shows the variability in the 5~7 month band, and dash line shows the variability in the 2.5~4.5 month band"

Fig. 11

Time-longitude plots of zonal wind stress and time-station plots of sea level anomaly. (a) Zonal wind stress in the 170~190 day band; (b) Sea level anomaly in the 170~190 day band; (c) Zonal wind stress in the 75~135 day band; (d) Sea level anomaly in the 75~135 day band"

Fig. 12

Map showing wave propagation path. The green box indicates the region of zonal wind stress. The blue line indicates the wave propagation path. The red dots indicate the stations"

Fig. 13

Salt budget and mixed layer depth variation in Region A, with MLD for mixed layer depth, ds/dt for salinity monthly tendency, SUM for sum of the right-hand side of salt budget, fwf for freshwater flux, adv for sum of horizontal (zonal & meridional) advections and entrainment, and adv-x/y/z for zonal/meridional/vertical transports, respectively. (a, b, c): 5~7 month band; (d, e, f): 2.5~4.5 month band"

Fig. 14

Salt budget and mixed layer depth variation in Region B, with MLD for mixed layer depth, ds/dt for salinity monthly tendency, SUM for sum of the right-hand side of salt budget, fwf for freshwater flux, adv for sum of horizontal (zonal & meridional) advections and entrainment, and adv-x/y/z for zonal/meridional/vertical transports, respectively. (a, b, c): 5~7 month band; (d, e, f): 2.5~4.5 month band"