It's the same at ordinary times, but it's also related to typhoons.
The reasons why Zhoushan's seawater is yellow are as follows:
1. Sediment is alluvial and there are many suspended substances in the seawater
Zhoushan Archipelago is located at the mouth of Qiantang River, east of Hangzhou Bay, and also at the mouth of Yangtze River and Yongjiang River. A large amount of sediment from the mainland flows into this area. Due to the increase of suspended matter, seawater has larger particles, which is weak in absorbing green light and strong in scattering. The degree of absorption, reflection and scattering of light with different wavelengths is also different. So it is mostly light blue or yellow.
2. Being in the high tide area, the water has strong scouring effect, and the sediment is extremely difficult to sink
Zhoushan shallow water area has fine sediment on the seabed, and the mud on the seabed is easily stirred up under the action of seawater tidal force (the seawater fluctuates twice a day).
Extended information:
The sea water in Zhoushan is relatively bluer than that in winter:
Due to the influence of wind, the northwest wind and the north wind blow more in Zhoushan in winter, and the southeast wind and the south wind blow more in summer.
In winter, under the action of northwest wind and north wind, the muddy water near the mainland moves eastward as a whole, and even the waters farther away become turbid.
after the spring, the wind turns to the southeast wind and the south wind. Under the action of wind, the clear water in the ocean moves to the west as a whole, and the muddy seawater on the shore no longer spreads outward, so the scope of clear water is correspondingly expanded.
Reference: Zhejiang News-Is Zhoushan seawater yellow? The truth behind it is here.