Spatiotemporal distribution characteristics of sea ice disasters in the Northern China Sea from 2001 to 2020

The sea ice disaster is one of the major marine disasters in China. The presence of sea ice poses a potential threat to the social-environmental system in the Northern China Sea during winter. The study focused on investigating the spatiotemporal distribution characteristics of sea ice disasters in the Northern China Sea during 2001-2020, including exploring the variation of sea ice hazards, climate drivers influencing sea ice occurrence, and the subsequent impacts on maritime activity and marine aquaculture. The results show that the sea ice grade in the Bohai and Northern Yellow Seas (BNYS) exhibited a slight downward trend (-0.40/decade, P > 0.10) during the past two decades. The winter temperature and the frequency of cold waves are the primary local climate factors for sea ice variation. The decrease in sea ice grade in the BNYS due to global climate change does not eliminate the occurrence of extreme events. However, the potential for more severe damages remains. It is worth noting that the winters of 2010, 2011, and 2013 stand out as periods with the highest recorded direct economic losses caused by sea ice hazards. In terms of spatial distribution, Liaoning and Shandong provinces have experienced the most severe impacts of sea ice hazards. Sea ice has a negative impact on the throughput of ports that are influenced by sea ice. Significant moderate negative correlations (r =-0.40, P < 0.10) have been observed between port throughput and the sea ice index in Yingkou, Jinzhou, and Tianjin ports. Moreover, the mariculture industry emerged as the primary sector affected by sea ice disasters in the Northern China Sea between 2001 and 2020. Attention should be paid to Haizhou Bay shortly as marine aquaculture in this area has been seriously affected by sea ice in the past five years. In the future, it is crucial to prioritize more accurate and refined monitoring and forecasting of sea ice, enhance the provision of effective icebreaking and pilot services, and optimize the fishery industry structure to prevent sea ice disasters in the Northern China Sea.