Will the sea freeze?

The sea will freeze.

Sea water will freeze at minus 1.5 degrees Celsius to 2 degrees Celsius, and sea ice appears every winter in the Bohai Sea and the northern Yellow Sea. Generally, it starts to freeze in late November every year and ends in mid-March of the following year. From the first ice day to the last ice day, it is divided into the first ice period, the severe ice period and the last ice period.

However, the freezing conditions of seawater are different from that of fresh water. Seawater contains a large amount of salt, which makes its freezing point lower than 0°C. Generally speaking, the freezing point of seawater is around -1.9°C, which means that seawater will not freeze immediately even if the temperature is below 0°C.

In addition, the density of seawater will also affect the possibility of freezing. The maximum density of seawater is not at 4°C, but decreases as salinity increases. This results in seawater not reaching its maximum density when it reaches the freezing point, thus hindering the convective mixing of seawater and preventing seawater from freezing.

The process of sea water freezing

The physical process of sea water freezing is relatively complex. The cold weather causes the sea surface temperature to drop, and strong winds stir the sea water, causing the surface layer of the sea water to lose heat and the sea water is cooled. Sea water temperatures drop. When the temperature of the surface seawater is close to the temperature at which the density of seawater is maximum, the specific gravity of the upper seawater becomes larger and sinks, while the specific gravity of the lower seawater becomes relatively smaller and rises to the surface.

Convective mixing will occur between the surface layer and the lower layer of seawater. As a result, the cooling process brings the cooling water from the surface layer to the lower layer, and then brings the crystalline heat released when the ice crystals form in the lower layer to the sea surface, and the sea water is cooled again.

It will not stop until the density of the entire seawater sinking and rising water layer is uniform and stable. Seawater begins to freeze when its temperature drops to freezing point and continues to lose heat. Sea ice formation can begin in any layer of ocean water, or it can freeze at the bottom of the ocean if mixing is intense all the way to the ocean floor.

Reference for the above content: Baidu Encyclopedia - Seawater Freezing Point