北極と亜北極の淡水循環における軌道の変化
Bruce J Peterson1, James McClelland, Ruth Curry
1Ecosystems Center, Marine Biological Laboratory, Woods Hole, MA 02543, USA. peterson@mbl.edu
Science (New York, N.Y.)
|August 26, 2006
まとめ
高緯度の淡水系では大きな変化が見られます. 50年以上にわたり,河川の排水量,降水量,海氷の減少,氷河の融解が増加し,北極海と北大西洋の海に大量の淡水が加えられました.
科学分野:
- 地球科学 地球科学 地球科学
- 海洋学 海洋学 海洋学
- 気候科学 気候科学
背景:
- 高緯度の地域の淡水循環に重大な変化が観察されています.
- 淡水源と海洋貯蔵の包括的な合成は,過去50年間のパターンを明らかにします.
研究 の 目的:
- 高緯度地域における淡水源と海洋貯蔵量の変化を合成する.
- 過去50年にわたるこれらの淡水循環の変化の時間的パターンと大きさを説明するために.
主な方法:
- 川の排水,純降水,海氷の消耗,氷河の融解による淡水投入の分析.
- 北極海と北大西洋の海洋淡水貯蔵データの合成.
- 淡水の変化と北大西洋振動や気温などの気候パターンとの相関関係.
主要な成果:
- 川の排水異常と過度の純降水により,約2万立方キロメートルの淡水が供給されました.
- 海氷の消耗により約1万5千立方キロメートル,氷河の融解により約2000立方キロメートルが増加した.
- 異常な淡水輸入は,1965年から1995年の北大西洋の蓄積率に匹敵し,北大西洋振動と気温上昇と一致しました.
結論:
- 北大西洋の淡水蓄積は,様々な源からの投入量の増加によるものです.
- これらの変化は,北大西洋振動の増幅と気温上昇に関連しています.
- 淡水は現在北極海に蓄積している可能性があり,将来の北大西洋振動段階では南に輸出される可能性があります.
関連する概念動画
00:53Migration
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.
01:19Magnetic Declination
Magnetic declination is the angle between true north, which aligns with the Earth's rotational axis, and magnetic north, which follows the direction of the Earth's magnetic field. This discrepancy exists because the magnetic poles do not coincide with the geographic poles. The value of magnetic declination depends on the observer's location on Earth and is subject to changes over time due to the dynamic nature of the Earth's magnetic field.The declination is called eastern when magnetic north...
01:27Latitudes and Departures
Latitudes and departures are essential concepts in surveying, providing a systematic way to analyze the projections of traverse lines. These projections allow surveyors to interpret a line's north-south and east-west components, which are crucial for precisely calculating areas, bearings, and lengths. Latitude is the north-south projection of a line, calculated as the product of the line's length and the cosine of its bearing. Departure, conversely, is the east-west projection obtained by...
01:22Net Change Theorem
The Net Change Theorem is a fundamental principle in calculus that establishes a direct relationship between a function’s rate of change and its accumulated change over an interval. Mathematically, it states that the definite integral of a function's derivative over a given interval [a,b] yields the net change in the original function:This theorem has significant applications in various real-world scenarios, including physics, economics, and engineering. A particularly useful application is in...
01:18Deep Sea Microbial Ecology
The deep ocean and its underlying sediments represent vast, largely unexplored microbial habitats that extend far beyond the sunlit photic zone. The photic (euphotic) zone typically spans the upper ~100–200 meters of pelagic waters in the open ocean, but its depth varies geographically and seasonally, where sufficient light supports photosynthetic life. Below this lies the deep sea, spanning roughly 1000–6000 meters (bathypelagic to abyssal zones), with deeper hadal trenches extending beyond...
01:24Freshwater Microbial Ecology
Freshwater systems such as streams, rivers, and lakes exhibit distinct physical and biological characteristics that influence their microbial communities. These environments are broadly categorized into lotic systems—those with flowing waters like streams and most rivers—and lentic systems, which include still or slow-moving waters such as lakes, ponds, and marshes.In lentic systems, phytoplankton drive primary production, generating autochthonous organic carbon. In contrast, lotic systems...