Will the sea water freeze?

Sea water will freeze at-1.5℃ to 2℃, and sea ice will appear in Bohai Sea and northern Yellow Sea every winter. Generally, it starts to freeze at the end of 165438+ 10 every year and ends in the middle of March of the following year. From the first glacial period to the last glacial period, it can be divided into the first glacial period, the severe glacial period and the last glacial period.

However, the freezing conditions of seawater are different from those of fresh water. Seawater contains a lot of salt, which makes its freezing point lower than 0℃. Generally speaking, the freezing point of seawater is about-1.9℃, which means that even if the temperature is lower than 0℃, seawater will not freeze immediately.

In addition, the density of seawater will also affect the possibility of freezing. The maximum density of seawater is not at 4℃, but decreases with the increase of salinity, which leads to the seawater not reaching the maximum density when it reaches the freezing point, thus hindering the convective mixing and freezing of seawater.

The freezing process of the ocean

The physical process of seawater freezing is complicated. The cold current weather makes the sea surface temperature drop, and the strong wind stirs the sea water, so that the surface of the sea water dissipates heat and the sea water cools down. The temperature of seawater drops. When the temperature of the surface seawater approaches the temperature when the seawater density reaches the maximum, the specific gravity of the upper seawater becomes larger and sinks, while the specific gravity of the lower seawater becomes relatively smaller and will rise to the surface.

Convective mixing will occur between the surface and bottom seawater. As a result, the cooling process brought the cooling water from the surface layer to the lower layer, and brought the crystalline tropical zone released during the formation of ice crystals from the lower layer to the sea surface, and the seawater was cooled again.

It doesn't stop until the whole sea water rises and falls and the density of the water layer is uniform and stable. When the temperature of seawater drops to freezing point and continues to dissipate heat, seawater begins to freeze. The formation of sea ice can start from any layer of seawater, and if it is strongly mixed with the seabed, it can also be frozen on the seabed.

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