The effect of astronomical forcing on water cycle: Sea ice and precipitation (in Chinese)

• Published in: Chinese Science Bulletin
• Main Authors: Wu, Zhipeng, Yin, Qiuzhen, Liang, Mingqiang, Guo, Zhengtang, Shi, Feng, Lu, Hao, Su, Qianqian, Lyu, Anqi
• Other Authors: UCL - SST/ELI/ELIC - Earth & Climate
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Zhongguo Kexue Zazhishe 2023
• Subjects: water cycle; precipitation; sea ice; orbital forcing; ice sheets; high-low latitudes interactions; Arctic; Arctic Ocean; Southern Ocean; Sea ice
• Online Access: http://hdl.handle.net/2078.1/268996; https://doi.org/10.1360/TB-2022-0833

Understanding the variations of water cycle on orbital timescale and their response to astronomical parameters, greenhouse gases (GHG) and ice sheets is one of the focuses in paleoclimate study. Sea ice and precipitation, two important components of the water cycle, are paid much attention. A better understanding of their variations on orbital timescale, especially their response to external forcing and related processes and feedbacks, could provide insight on their long-term variations in the future. The latest research results show that, on orbital scale, the Arctic sea ice is more sensitive to insolation, while the Southern Ocean sea ice is more sensitive to GHG. Under the combined influence of insolation and GHG, the last nine interglacials all have much less summer Arctic sea ice, as compared to both the present-day and the future, due to the much higher Northern Hemisphere (NH) summer insolation. As compared to the future, the last nine interglacials all have much more annual and seasonal Southern Ocean sea ice due to their much lower CO2. In terms of the astronomical parameters, the Arctic sea ice is more influenced by precession, whereas obliquity plays a more important role in the Southern Ocean sea ice. The different responses of Arctic and Southern Ocean sea ice to astronomical parameters and CO2 are mainly due to their different geographical locations. The Arctic ocean is relatively closed and it is located in the northern highest latitudes, which make it only receives very little insolation during winter and it is mainly influenced by precession-dominated summer insolation. The summer insolation not only influences the summer Arctic sea ice, but also has an effect on the winter one through the summer remnant effect. In addition, the Arctic sea ice is also affected by the vegetation in the northern mid and high latitudes, which is mainly dominated by precession. As compared to the Arctic, the latitudes of Southern Ocean are lower and it is more open, which make it is more sensitive to the annual ...