Intensity division of the sea ice zones in China

The intensity division of sea ice regions can provide useful information for disaster prevention. According to different ice conditions, the Bohai Sea and the northern part of the Yellow Sea in China have been divided into twenty-one ice zones, and subsequently grouped in five intensity levels. But this division has many discrepancies and cannot reflect most of the properties of the ice zones. Based on the multivariate statistical sample of the twenty-one ice zones, the principal component analysis and hierarchical cluster analysis are applied to obtain a new intensity division. The cluster results indicate that, the regionalization obtained by the Ward method is recommended. The new criteria increases the number of sea ice zones with higher intensity levels. It is more practical and more conservative for the disaster prevention of marine structures. In addition, this method can present any groups of the intensity division wanted, so it provides more possibilities and flexibility for the application.