16摄氏度,格陵兰中部温度的快速变化 7万年前
1Climate and Environmental Physics, Physics Institute, University of Bern, Sidlerstrasse 5, Bern CH-3012, Switzerland. Niels Bohr Institute, Department of Geophysics, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen, Den.
概括
研究人员分析了格陵兰岛冰核中的同位素,以重建过去的气候. 他们发现,在过去的气候事件中,气温发生了16凯尔文的显著变化,与之前的估计不同.
科学领域:
- 古气候学 古气候学
- 冰川学的冰川学
- 同位素地球化学 同位素地球化学
背景情况:
- 极地冰芯中的同位素比率 (29N2/28N2) 与过去的表面温度和冰河时代气体年龄差异相关.
- 了解这些关系对于准确重建古气候条件至关重要.
研究的目的:
- 在特定的古气候事件中精确确定过去的表面温度变化和冰河时代-气体年龄差异.
- 为了改进三角洲温度系数的校准.
主要方法:
- 在Dansgaard-Oeschger事件中的格陵兰冰芯样本中对同位素比率 (29N2/28N2) 的高分辨率分析 19.
- 应用一个结合的燃烧密度,温度和气体扩散模型.
- 确定三角洲温度系数 (alpha).
主要成果:
- 在Dansgaard-Oeschger事件19开始时的冰河时代-气体年龄差异被计算为1090 +/- 100年.
- 确定三角洲温度系数 (α) 为0.42 +/- 0.05每毫克/克尔文.
- 这意味着在事件期间的平均表面温度变化为16.0凯尔文 (范围:14.318.1凯尔文).
结论:
- 计算的温度变化与使用钻井温度和现代空间三角洲-冰表面温度相关性得到的值有显著差异.
- 这项研究提供了一个更准确的古气候重建格陵兰在Dansgaard-Oeschger事件期间.
- 冰芯中同位素分析是了解过去气候动态的宝贵工具.
相关概念视频
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.
Le Chatelier's Principle: Changing Temperature
Consistent with the law of mass action, an equilibrium stressed by a change in concentration will shift to re-establish equilibrium without any change in the value of the equilibrium constant, K. When an equilibrium shifts in response to a temperature change, however, it is re-established with a different relative composition that exhibits a different value for the equilibrium constant.
To understand this phenomenon, consider the elementary reaction:
To understand this phenomenon, consider the elementary reaction:
Temperature Measurement Sites
A thermometer measures body temperature. The common sites for measuring body temperature are the oral cavity, axillary region, temporal artery, and skin surface, such as the forehead, abdomen, and axilla. True core body temperature is assessed in the rectum, tympanic membrane, pulmonary artery, esophagus, and urinary bladder.
Oral: When assessing oral temperature, the thermometer tip should be placed under the tongue in the posterior sublingual pocket. It offers accurate readings and can be...
Oral: When assessing oral temperature, the thermometer tip should be placed under the tongue in the posterior sublingual pocket. It offers accurate readings and can be...
Factors Influencing Microbial Growth: Temperature
Microorganisms display remarkable adaptations, enabling them to thrive in diverse ecological niches across a wide range of temperatures. Temperature profoundly influences microbial growth by affecting enzymatic activity, membrane fluidity, and other cellular processes.Each microorganism operates within a specific temperature range defined by three cardinal points: minimum, optimum, and maximum. Below the minimum temperature, membranes lose fluidity, halting transport processes. Above the...
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...


