Fig. 7

Relationship between tidal phase angle and the seven dominant tidal level indices in region Sd. a ΔV, b Δτ, c ΔCFF_(0.1), d ΔCFF_(0.2), e ΔCFF_(0.3), f ΔCFF_(0.4), and g ΔCFF_(0.5). When the phase angle was in the range of − 90° to + 90°, the tidal level was generally positive, and generally negative otherwise (white areas in each panel). However, there were some exceptional events that fall into the gray area