Morphometry and internal structure of large ice ridges and stamukhas in the Kara, Laptev and East Siberian seas

• Consolidated layer thickness has the highest correlation with the age of ridge, freezing degree-days, and level ice thickness • An increase in the keel draft is reflected in an increase of the consolidated layer thickness • The porosity of the sail and the unconsolidated keel has an inverse relationship with sail height and keel depth, respectively • The correlation between the consolidated layer thickness and external parameters (sail height, keel depth, and cross-section area) of ridges is either insignificant or positive • The greatest potential threats to offshore structures and ice navigation are stamukhas and composite old ridges Morphometric characteristics of 155 ice ridges and stamukhas measured during 2013-2017 in the Kara, Laptev and East Siberian seas are presented. The joint use of ice drift reanalysis with temperature reanalysis enabled confident determination of the ridges’ regional origin. Correlation coefficients between the average thickness of the consolidated layer (CL) of ice features and various parameters affecting consolidation were computed. The highest correlation with average CL thickness in ridges is observed with the age of the ridge, freezing degree-days, and level ice thickness. Relationships between the external morphometric parameters (sail height, keel depth, total thickness and cross-section area) and distributions of porosity and CL are examined. We find: thickening of the CL in the central part of the ridge; an increase in the keel draft is reflected in an increase of the CL thickness. Porosity of the sail and the unconsolidated part of the keel is higher for small ridges; in most cases, ridges with the largest average sail correspond to the smallest sail porosity, and vice versa. The depth of the average keel and the porosity of the unconsolidated part of the keel are also inversely proportional. The results of this study can be used for ridge modeling and defining the potential ice loads on offshore facilities from large ice features in freezing seas.