Gulf of Ob, satellite image. This gulf is the estuary of the Ob River, and is located on the north-western coast of Siberia, Russia. The Gulf of Ob opens northwards into the Kara Sea of the Arctic Ocean. The mouth of the Ob River is at lower left. The Taz Estuary and river are at upper right. At upper left is another bay of the Kara Sea. Composite image obtained using data from the Landsat 5 satellite.