Temporal and spatial variations of suspended particulate matter (SPM) in Tokyo Bay were investigated based on intensive field surveys and numerical simulation. Measurement results showed that the relative high turbidity appeared in the front of bottom high saline water and the middle turbid layer was generated corresponding to the middle hypoxic water generation induced by the intrusion of offshore oceanic water. The neutral tracer tracking simulation shows that bottom SPM have a characteristic to distribute along the front of bottom high saline water which forms the streak pattern from off Tama river mouth to off Chiba port in the south wind period and moves to the head region in north wind period. Furthermore the neutral tracer tracking and water quality simulations revealed that the bottom SPM can be moved upward by the intrusion of oceanic water in the bottom layer due to the change of wind direction or offshore water variations.
