海平面变化的幅度和起源
G R Grant1,2, T R Naish3, G B Dunbar3
1Antarctic Research Centre, Victoria University of Wellington, Wellington, New Zealand. g.grant@gns.cri.nz.
Nature
|October 4, 2019
概括
地球
科学领域:
- 古气候学
- 海洋地质学
- 气候科学
背景情况:
- 地球目前的轨迹反映了大气中高二氧化碳的普略纪中期温暖时期 (3.3-2.5万年).
- 在过去的温暖时期,全球平均海平面 (GMSL) 显著上升,可能比现在高出20米.
- 了解过去的海平面变化对于预测未来的冰盖行为和GMSL变化至关重要.
研究的目的:
- 重建和量化平世中后期的相对海平面 (RSL) 变化.
- 在过去温暖的气候条件下限制极地冰量变化.
- 为验证预测未来海平面上升的气候模型提供新的数据.
主要方法:
- 在波动驱动的沉积物和水深之间进行了理论校准.
- 应用这种技术来分析来自新西兰瓦努伊盆地的800米长的平纪沉积物核心的粒度.
- 对构造沉降的水深变化进行了校正,以获得周期性RSL变化.
主要成果:
- 在冰川-间冰川周期 (3.3-2.5万年) 中重建的周期性RSL变化平均为13±5米.
- 证明这些海平面周期是由南极阳光变化 (20-kyr周期) 和地球轴倾斜 (41-kyr周期) 带来的.
- 据估计,纪最大海平面上升不到25米,限制了冰盖的行为.
结论:
- 这项研究提供了一个新的,独立的普略纪海平面波动记录.
- 结果提供了极地冰盖在持续温暖气候条件下的动态.
- 这些发现有助于更准确地预测未来的全球海平面上升.
相关概念视频
Global Climate Change
28.6K
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.
28.6K
Tidal Forces
3.2K
The origin of Earth's ocean tides has been a subject of continuous investigation for over 2000 years. However, the work of Newton is considered to be the beginning of the proper understanding of the phenomenon. Ocean tides are the result of gravitational tidal forces. These same tidal forces are present in any astronomical body; they are responsible for the internal heat that creates the volcanic activity on Io, one of Jupiter's moons, and the breakup of stars that get too close to...
3.2K
Influence of Earth's Curvature and Atmospheric Refraction on Leveling
816
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...
816
Diversity of Protists III
697
Rhizaria are a diverse group of unicellular protists characterized by their threadlike cytoplasmic extensions known as pseudopodia. These structures aid in both locomotion and feeding, giving Rhizaria an amoeboid appearance. Their amoeboid morphology once led to taxonomic confusion, but molecular phylogenetics has clarified their evolutionary placement and emphasized their shared use of pseudopodia despite divergent lineages.This clade comprises diverse lineages such as Chlorarachniophyta,...
697
Speciation Rates
22.5K
Overview
22.5K
The Fossil Record
27.0K
The fossil record documents only a small fraction of all organisms that have ever inhabited Earth. Fossilization is a rare process, and most organisms never become fossils. Moreover, the fossil record only exhibits fossils that have been discovered. Nevertheless, sedimentary rock fossils of long-lived, abundant, hard-bodied organisms dominate the fossil record. These fossils offer valuable information, such as an organism's physical form, behavior, and age. Studying the fossil record helps...
27.0K


