Identification of biophysical regions in the south-western part of the Okhotsk Sea by satellite imagery classification

• Water masses classification based on Hierarchical Ascending Classification method.
• Classification of chlorophyll a, SST and SST gradient satellite data.
• Six classes explained main patterns and important characteristics of the region.
• Method reflects the presence of major circulation patterns occurring in the area.
• Able to identify seasonal and interannual variations.

Water properties in the south-western part of the Okhotsk Sea show strong seasonal variability. This study applied a method based on Hierarchical Ascending Classification to classify biophysical regions using satellite data and to determine the seasonal variation of the characteristics of water masses in the area. Water masses in the same biophysical region have similar physical and biological characteristics and are able to explain the biological and physical processes in the ocean. This method provided classification of chlorophyll a, SST and SST gradient satellite data. Six classes explained the main patterns and important characteristics of the region. The method was also able to determine interannual variability in existence and area size of the classes which indicated occurrences of the major circulation patterns in the area and its influence on the variations of the classes.