Mesoscale Circulation in the East Sakhalin Current Region (Okhotsk Sea)
The seasonal and interannual variability of mesoscale circulation along the eastern coast of Sakhalin Island (the western Okhotsk Sea) for the period from 1993 to 2014 has been investigated using AVISO velocity field and cruise data. We identified that mesoscale cyclones (horizontal dimension of 100 km) are produced predominantly during summer, whereas anticyclones are generated predominantly during fall-winter (Octo-ber-December). The mesoscale cyclones generation is related to the coastal upwelling forcing by positive wind stress curl over the Okhotsk Sea and northward winds along the Sakhalin coast. The anticyclones formation is related to inflow of low salinity waters from the Sakhalin Bay forced by negative wind stress curl over the Okhotsk Sea and southward winds along the Sakhalin coast. The mesoscale cyclones provide the cross shelf - edge exchange by nutrients and thereby support the high biological productivity on the eastern Sakhalin shelf in July-August.