First mate Zhu Pengtao (L) and sailor Chen Dongbin adjust the navigation course aboard China's research icebreaker Xuelong 2. Currently on China's 41st Antarctic expedition, research icebreakers Xuelong and Xuelong 2, or Snow Dragon and Snow Dragon 2, will begin to plough through the belt of prevailing westerlies, nicknamed the "rolling forties," on Tuesday. (Xinhua/Huang Taoming)