Severnaya Zemlya broader Shokalsky Strait Bolshevik Island from October Revolution Island. Both straits connect the Kara Sea in the west with the Laptev Sea in the east. This archipelago encloses the northern limits of the Kara Sea on its western shores, together with Novaya Zemlya, located roughly to the southwest. The big rivers Ob and Yenisei, among others, flow from the south into this marginal sea area of the Arctic Ocean, with their abundant waters contributing to a climate with relatively high precipitation despite the prevalent extreme cold temperatures of the high latitude. The Laptev Sea, where the mighty Lena River steadily
Convoy PQ 18 against Russian ships thought to be sailing along the route north of Siberia. "Admiral Scheer" sailed north of Novaya Zemlya and then to the east and sank a Soviet icebreaker. By 30 August "Admiral Scheer" was back in Narvik. "B-Dienst" signals interception and documents recovered from a crashed Hampden, revealed details about the PQ 18 and QP 14 convoys, including their crossover and escort changeover points. U-boats, destroyers and the minelayer "Ulm" sailed on Operation Zar ("Unternehmen Zar") to sow mines at the entrance of the White Sea and off Novaya Zemlya. On 25 August, Ultra revealed the itinerary of