Temporal and spatial distributions of TEC depletions with scintillations and ROTI over south China

•TEC depletions with scintillations and ROTI over south China were investigated.•The maximum distributions of TEC depletions were in vernal and autumnal equinox months.•Deep TEC depletions well coincided with the intense scintillations and large ROTI.•Around midnight hours or at the outer edge of northern anomaly crest, shallow TEC depletions were recorded.•Temporal and spatial variability of TEC depletions could be a representative of the evolution phase of the plasma bubbles.