氷河気候の調節器としての亜熱帯フロントの移動

Edouard Bard¹, Rosalind E M Rickaby

¹CEREGE (UMR 6635), Collège de France, University Paul-Cézanne Aix-Marseille, CNRS, IRD, Europole de l'Arbois BP 80, 13545 Aix-en-Provence Cedex 4, France.

Nature

|July 17, 2009

まとめ

氷河期は,氷芯データとは対照的に,激度が変動した. サブトロピカルフロントの北へのシフトはアグルハス流を制御し,熱伝送と氷河の強さを調節しました.

科学分野:

古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは,古代気候学 (paleoclimatology) とは
海洋学海洋学とは
気候科学気候科学

背景:

氷芯は,過去80万年にわたる恒常的な氷河状態と大気中のCO2レベルを示唆しています.
矛盾する証拠は,特に海洋同位体段階10および12の間,氷河の重度の変動を示しています.
これは,太陽照射,CO2と気候の関係を媒介する未知のメカニズムを示唆しています.

研究の目的:

アグルハス流の熱と塩の輸送を調節するサブ熱帯フロント (STF) 移動の役割を調査する.
STFシフトがインド太平洋から大西洋への熱伝達のゲートキーパーとして機能するかどうかをテストする.
大気中のCO2レベルが一貫しているにもかかわらず,氷河の振幅が変化しているパズルの解明です.

主な方法:

沈殿体核MD962077.7.からの80万年の海面温度と海洋生産性の記録の分析
海洋学データと海洋同位体段階,特にステージ10とステージ12との相関.
発見を南大西洋の動物集団と統合する.

主要な成果:

冷たいスタジアム (MIS 10 & 12) の間には,海洋の生産性がピークに達し,海面の温度は著しく下がった.
証拠によると,STFはこれらのスタジアム中に北へ北緯7度まで移動し,アグルハス流をほとんど止めました.
この北向きのSTF移動は,熱と塩の運搬を大西洋南極逆転循環に変化させた.

結論:

南半球のSTFの北への移動は,アグルハス流に影響することによって,氷河期の重さを調節します.
STFの移住は,地球気候と大気中のCO2レベルを切り離すことができる.
このメカニズムは,安定した大気中のCO2範囲内で異なる氷河幅を説明するのに役立ちます.

さらに関連する動画

06:10

Using Generative Art to Convey Past and Future Climate Transitions

Published on: March 31, 2023

1.6K

10:14

Author Spotlight: Leaf Trait Analysis for Climate and Ecology Reconstruction in Modern and Ancient Plant Communities

Published on: October 25, 2024

4.3K

関連する概念動画

00:53

Migration

9.1K

Migration is long-range, seasonal movement from one region or habitat to another. This common strategy, carried out by many different organisms around the world, is an adaptive response that typically corresponds to changes in an organism’s environment, like resource availability or climate. Migrations can involve huge groups of thousands of animals as well as single individuals traveling alone and can range from thousands of kilometers to just a few hundred meters.

9.1K

01:16

What is Climate?

21.6K

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.

21.6K

01:50

Global Climate Change

29.8K

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.

29.8K

02:39

Gene Flow

39.1K

Gene flow is the transfer of genes among populations, resulting from either the dispersal of gametes or from the migration of individuals.

39.1K

01:12

Precipitation Processes

6.6K

The experimental conditions in a gravimetric analysis should be optimized to maximize the particle size and purity of the obtained precipitate. Ideally, the concentration of the precipitating reagent should be low with effective stirring to maintain low relative supersaturation for the growth of large crystals. In homogeneous precipitation, the precipitant is slowly generated by a chemical reaction in the solution to avoid local reagent excesses. For example, urea decomposes gradually to...

6.6K

01:27

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...

関連する実験動画