热力学上不一致的极端降水灵敏度跨越大陆是由云辐射效应驱动的
Sarosh Alam Ghausi1,2,3, Erwin Zehe4, Subimal Ghosh5,6
1Biospheric Theory and Modelling Group, Max Planck Institute for Biogeochemistry, Jena, Germany. sghausi@bgc-jena.mpg.de.
Nature communications
|December 11, 2024
概括
全球变暖加剧了极端降雨,但云效应掩盖了这一趋势. 新的分析揭示了整个大陆的极端降水温度敏感性,与气候预测保持一致.
科学领域:
- 气候科学 气候科学
- 大气物理学 大气物理学
- 水文学的水文学
背景情况:
- 全球变暖预计将增加极端降水事件的强度.
- 基于观察的极端降水-温度 (EP-T) 灵敏度估计显示出显著的空间和时间变化.
- 在温暖的地区经常观察到负的EP-T灵敏度,这与理论预期相矛盾.
研究的目的:
- 调查EP-T灵敏度观察到的变化背后的原因.
- 识别和消除影响EP-T灵敏度估计的混因素.
- 为了更准确地评估极端降水如何与温度加剧.
主要方法:
- 使用热力学约束的表面能量平衡模型.
- 从观测数据中量化和删除混云辐射效应.
- 分析了不同度带 (热带,中度) 的EP-T灵敏度.
主要成果:
- 云的辐射效应被确定为一个重要的混因素,引入降雨和温度之间的人工共变.
- 在消除了云效应后,在整个大陆地区发现了积极的EP-T灵敏度.
- 平均EP-T灵敏度从负值转变为正值,特别是在热带地区 (从-4.9%/°C到6.1%/°C).
- 估计灵敏度的区域变异性大幅下降 (热带地区超过40%,中度地区30%).
结论:
- 随着全球气温的上升,极端降雨的预计加剧与当考虑混云辐射效应时的观测数据相一致.
- 这项研究将观察估计与EP-T关系的理论预测相协调.
- 准确评估EP-T的敏感性对于理解和预测未来的洪水风险和生态系统影响至关重要.
相关概念视频
01:16What is Climate?
18.4K
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.
18.4K
01:50Global Climate Change
24.2K
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.
24.2K
01:07What is Weather?
18.2K
Overview
18.2K
01:17Radiation: Applications
1.1K
The average temperature of Earth is the subject of much current discussion. Earth is in radiative contact with both the Sun and dark space; it receives almost all its energy from the radiation of the Sun and reflects some of it into outer space. Dark space is very cold, about 3 K, so Earth radiates energy into it. For instance, heat transfer occurs from soil and grasses, the rate of which can be so rapid that frost can occur on clear summer evenings, even in warm latitudes.
The average...
The average...
1.1K
01:18Variation of Atmospheric Pressure
2.1K
Change in atmospheric pressure with height is particularly interesting. The decrease in atmospheric pressure with increasing altitude is due to the decreasing gravitational force per unit area as we move away from the surface of the earth.
Assuming the air temperature is constant at a given altitude and that the ideal gas law of thermodynamics describes the atmosphere to a good approximation, one can find the variation of atmospheric pressure with height.
Let p(y) be the atmospheric pressure at...
Assuming the air temperature is constant at a given altitude and that the ideal gas law of thermodynamics describes the atmosphere to a good approximation, one can find the variation of atmospheric pressure with height.
Let p(y) be the atmospheric pressure at...
2.1K
01:26Influence of Earth's Curvature and Atmospheric Refraction on Leveling
54
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.
54