When it comes to natural disasters in the ocean, we are most familiar with typhoons and tsunamis. These marine disasters, which are often reported in TV and radio programs, have had a great impact on the production and life of people living in the coastal zone. But I'm afraid few people will notice that the ocean will also be threatened by serious sea ice disasters.
Sea ice disaster refers to the phenomenon that continuous ultra-low air temperature at sea leads to large-scale freezing of surface seawater, which mainly occurs in inland sea, bay and offshore areas. When sea ice disaster occurs, the sea surface is frozen by sea ice, and the thickness of sea ice can reach tens of centimeters to several meters. China's Bohai Sea and parts of the northern Yellow Sea have been hit by sea ice disasters on several occasions.
In December 2009, under the continuous invasion of cold air, the magnificent Bohai Sea and the northern Yellow Sea successively appeared the phenomenon of seawater freezing. From January 4 to 8, 2010, the scope of sea ice in the sea area expanded rapidly and developed into the most serious ice condition in the same period in 30 years, which lasted until February 2010. The once surging coast of the Yellow Sea and the Bohai Sea changed from dynamic to static in an instant, covered by thick white ice and snow, and solidified into a world of "ice sculpture". In this ice disaster, more than 50% of the Bohai Sea was frozen by sea ice.
Coincidentally, the Bohai Sea experienced a more serious sea ice disaster in 1967. In that terrible ice disaster, the whole Bohai Bay was completely frozen, and the average thickness of sea ice was more than half a meter. The originally wide sea surface "changed" into a huge ice and snow plain, as if the vast Bohai Sea had never existed. The icebound ships stand alone on the ice and snow, highlighting the ruthlessness and coldness of the sea ice disaster.
Fortunately, sea ice disaster is not a frequent extreme marine disaster event. In fact, the formation of sea ice disaster requires more severe climatic conditions. Among them, sustained low temperature, large-scale snowfall and extreme cold air attack in the early stage are important conditions for the formation of serious sea ice disasters. Continuous low temperature will reduce the temperature of sea water in the sea area and make "warm-up" preparations for the formation of sea ice; The occurrence of large-scale snowfall can provide condensation nodules needed for sea ice crystallization and promote the formation of sea ice on the sea surface; The arrival of extremely cold air will eventually lead to the rapid expansion of sea ice area. If we continue to encounter multiple cold air attacks, the sea water temperature may not have a chance to warm up, and the sea ice disaster will become more and more serious.
The large-scale sea ice disaster has caused great impact and harm to shipping, fishing, aquaculture, offshore oil exploitation and other industries. For the marine ecosystem, large-scale sea ice will also lead to the hypoxia of sea water and the change of sea water salinity. In serious cases, it will threaten the survival of marine fish and benthos and destroy the balance of regional ecological environment.