最近的地球平坦度变化:解开气候和冰期后反弹效应
Jean O Dickey1, Steven L Marcus, Olivier de Viron
1Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA. jean.o.dickey@jpl.nasa.gov
概括
由于冰川融化和海洋质量转移,地球的平坦度 (J2) 正在增加,而不仅仅是冰川后的反弹. 这些快速变化标志着全球物质的重大再分配,需要进一步的气候调查.
科学领域:
- 地质物理学 地质物理学
- 气候科学 气候科学
- 地球系统科学 地球系统科学
背景情况:
- 地球的动态平坦度 (J2) 在历史上由于冰期后反弹 (PGR) 而下降.
- 1997年,J2开始显著增加,这表明最近地球质量分布发生了变化.
- 这种转变表明地球系统内的全球规模的质量重新分配是显著的.
研究的目的:
- 确定地球动态平度 (J2) 最近增加的主要驱动因素.
- 为了使观察到的J2趋势与现有的冰川后反弹模型相协调.
- 评估冰川融化和海洋质量转移对J2变化的贡献.
主要方法:
- 使用卫星和日食数据对J2变化的分析.
- 量化极地冰盖和全球海洋的质量变化.
- J2的分解趋势是将PGR和其他因素的贡献孤立起来.
主要成果:
- 南极冰川融化和南方,太平洋和印度洋的海洋质量转移是最近J2增加的主要原因.
- 考虑到这些影响后,剩余的J2趋势与以前的PGR估计相一致 (-2.9 x 10^-11年^-1).
- 观测到的快速质量转移是地球平面变化的重要贡献者.
结论:
- 最近的J2增加主要是由当代气候相关的质量再分配驱动的,取代了PGR信号.
- 这些发现突出了地球旋转和引力场对气候变化的敏感性.
- 需要进一步的研究来了解这些快速的冰川和海洋质量转移对气候的影响.
相关概念视频
What is Weather?
Overview
What is Climate?
Climate refers to the prevailing weather conditions in a specific area over an extended period. As the saying goes, “Climate is what you expect. Weather is what you get.” Climate is influenced by geographic factors, such as latitude, terrain, and proximity to bodies of water.
Global Climate Change
Throughout its ~4.5 billion year history, the Earth has experienced periods of warming and cooling. However, the current drastic increase in global temperatures is well outside of the Earth’s cyclic norms, and evidence for human-caused global climate change is compelling. Paleoclimatology, the study of ancient climate conditions, provides ample evidence for human-caused global climate change by comparing recent conditions with those in the past.
Responses to Heat and Cold Stress
Every organism has an optimum temperature range within which healthy growth and physiological functioning can occur. At the ends of this range, there will be a minimum and maximum temperature that interrupt biological processes.
Influence of Earth's Curvature and Atmospheric Refraction on Leveling
During leveling, the Earth's curvature and atmospheric refraction introduce deviations in the line of sight from a true horizontal reference. When the line of sight is leveled, it remains perpendicular to the plumb line only at a single point. Beyond this, it deviates due to the Earth’s curvature, represented by the correction C. For a sight distance D, the deviation can be derived using the relationship:This relationship shows that the deviation increases quadratically with distance. Over a...
Microbes and Climate Change
Microorganisms are pivotal agents in Earth's biogeochemical cycles, significantly influencing climate dynamics through their metabolic activities. These microbes modulate the levels of key greenhouse gases by both contributing to and helping mitigate climate change.Microbial Contributions to Greenhouse Gas EmissionsRising global temperatures accelerate microbial metabolism, which, in turn, speeds up the decomposition of organic matter. This process releases carbon dioxide (CO₂) through...


