Photo taken on Jan. 29, 2020 shows iceberg seen from China's polar icebreaker Xuelong 2, or Snow Dragon 2, in the southern Ocean before Xuelong 2 crosses the prime meridian. Xuelong 2 crossed the prime meridian and entered the Western Hemisphere on Thursday. (Xinhua/Liu Shiping)

Photo taken on Jan. 29, 2020 shows iceberg seen from China's polar icebreaker Xuelong 2, or Snow Dragon 2, in the southern Ocean before Xuelong 2 crosses the prime meridian. Xuelong 2 crossed the prime meridian and entered the Western Hemisphere on Thursday. (Xinhua/Liu Shiping)

China's polar icebreaker Xuelong 2, or Snow Dragon 2, sails in the misty Southern Ocean on Jan. 30, 2020. Xuelong 2 crossed the prime meridian and entered the Western Hemisphere on Thursday. (Xinhua/Liu Shiping)

China's polar icebreaker Xuelong 2, or Snow Dragon 2, sails in the misty Southern Ocean on Jan. 30, 2020. Xuelong 2 crossed the prime meridian and entered the Western Hemisphere on Thursday. (Xinhua/Liu Shiping)