「終末の氷河」の下に押し寄せる海水、海面上昇を悪化させる可能性 新研究
Seawater surging beneath the ``Doomsday Glacier’’ could worsen sea level rise - new research
Seawater surging beneath the ``Doomsday Glacier’’ could worsen sea level rise - new research
南極西部のスウェイツ氷河では、氷河の下に数キロにわたって海水が押し寄せ、これまで考えられていたよりも融解しやすくなっていることが分かった
Thwaites Glacier in West Antarctica has been found to be flooded with seawater for several kilometers beneath the glacier, making it more susceptible to melting than previously thought.
Thwaites Glacier in West Antarctica has been found to be flooded with seawater for several kilometers beneath the glacier, making it more susceptible to melting than previously thought.
宇宙からのレーダーデータを使ってこの氷河をX線撮影した新しい研究によって明らかになった
A new study uses radar data from space to take X-ray images of this glacier.
A new study uses radar data from space to take X-ray images of this glacier.
米国科学アカデミー紀要に20日に発表された研究によると、塩分を含んだ比較的暖かい海水が流れ込むことで氷河の下で「活発な融解」が起こっており、地球全体の海面上昇の予測が過小評価されている可能性があるという
According to a study published in the Proceedings of the National Academy of Sciences on the 20th, ”active melting” is occurring under glaciers due to the inflow of relatively warm salty seawater, leading to underestimations of global sea level rise. It is said that there is a possibility that it has been evaluated.
According to a study published in the Proceedings of the National Academy of Sciences on the 20th, ”active melting” is occurring under glaciers due to the inflow of relatively warm salty seawater, leading to underestimations of global sea level rise. It is said that there is a possibility that it has been evaluated.
スウェイツ氷河は、その崩壊が壊滅的な海面上昇を引き起こす可能性があることから「終末の氷河」の異名を持つ
Thwaites Glacier is nicknamed the ”glacier of the end” because its collapse could cause catastrophic sea level rise.
Thwaites Glacier is nicknamed the ”glacier of the end” because its collapse could cause catastrophic sea level rise.
米フロリダ州に匹敵する面積を持つ世界最大のこの氷河は、南極で最も脆弱(ぜいじゃく)で不安定な氷河でもあるとされる
The world’s largest glacier, with an area comparable to the US state of Florida, is also said to be the most fragile and unstable glacier in Antarctica.
The world’s largest glacier, with an area comparable to the US state of Florida, is also said to be the most fragile and unstable glacier in Antarctica.
それは主に氷河のある地形が下向きに傾斜しており、海水が氷をむしばむためだ
This is mainly because the terrain where the glacier is located slopes downward, and seawater eats away at the ice.
This is mainly because the terrain where the glacier is located slopes downward, and seawater eats away at the ice.
すでに世界の海面上昇の4%を占めているスウェイツ氷河には、海面を60センチ以上上昇させるのに十分な氷がある
Already responsible for 4% of global sea level rise, Thwaites Glacier has enough ice to raise sea levels by more than 60 centimeters.
Already responsible for 4% of global sea level rise, Thwaites Glacier has enough ice to raise sea levels by more than 60 centimeters.
さらにこの氷河には南極西部の周囲の氷をせき止める天然のダムの役割も果たしているため、科学者たちはスウェイツ氷河が完全に崩壊すれば、最終的な海面上昇幅は約3メートルに達すると見積もっている
Scientists estimate that if Thwaites Glacier were to completely collapse, the ultimate sea level rise would be about 3 meters, as the glacier also acts as a natural dam to hold back the surrounding ice in West Antarctica. ing
Scientists estimate that if Thwaites Glacier were to completely collapse, the ultimate sea level rise would be about 3 meters, as the glacier also acts as a natural dam to hold back the surrounding ice in West Antarctica. ing
米カリフォルニア大学アーバイン校の科学者らが率いる氷河学者チームは、昨年3月から6月にかけて収集された高解像度の衛星レーダーデータを用いて氷河のX線画像を作成した
A team of glaciologists led by scientists from the University of California, Irvine created X-ray images of glaciers using high-resolution satellite radar data collected between March and June last year.
A team of glaciologists led by scientists from the University of California, Irvine created X-ray images of glaciers using high-resolution satellite radar data collected between March and June last year.
これにより、スウェイツ氷河の「接地線」(氷河が海底から隆起し、海に浮かぶ氷棚となるポイント)の変化を把握することができた
This enabled them to understand changes in Thwaites Glacier’s ”grounding line” (the point at which the glacier rises from the ocean floor and becomes an ice shelf floating in the ocean).
This enabled them to understand changes in Thwaites Glacier’s ”grounding line” (the point at which the glacier rises from the ocean floor and becomes an ice shelf floating in the ocean).
接地線は氷床の安定に不可欠であり、スウェイツ氷河の脆弱性を示す重要なポイントだが、これまで調査は困難だった
The grounding line is essential to the stability of the ice sheet and is an important point indicative of Thwaites Glacier’s vulnerability, but it has been difficult to investigate until now.
The grounding line is essential to the stability of the ice sheet and is an important point indicative of Thwaites Glacier’s vulnerability, but it has been difficult to investigate until now.
チームは、海水が何キロにもわたって氷河の下に流れ込み、潮の満ち引きに従って再び外に流れ出ていくのを観察した
The team observed seawater flowing for miles beneath the glacier and flowing out again as the tides rose and fell.
The team observed seawater flowing for miles beneath the glacier and flowing out again as the tides rose and fell.
海水が流れ込むと、氷河の表面を何センチも押し上げるという
When seawater flows in, it pushes the surface of the glacier up several centimeters.
When seawater flows in, it pushes the surface of the glacier up several centimeters.
研究によると、12時間の潮の満ち引きのサイクルによって接地線は6.4キロ近く移動する可能性があることから、研究者は接地線よりも「接地帯」という用語のほうが適切だと示唆している
The researchers suggested that the term ”grounding zone” is more appropriate than grounding line, as the study found that the grounding line can move nearly 4 miles during a 12-hour tidal cycle. are doing
The researchers suggested that the term ”grounding zone” is more appropriate than grounding line, as the study found that the grounding line can move nearly 4 miles during a 12-hour tidal cycle. are doing
短時間にかなりの距離を移動する海水の速度は、氷河の融解を促進する
The speed of seawater moving large distances in a short time accelerates the melting of glaciers
The speed of seawater moving large distances in a short time accelerates the melting of glaciers
これは氷が溶けるとすぐに淡水が洗い流され、より暖かい海水と入れ替わるからだという
This is because as soon as the ice melts, freshwater is washed away and replaced by warmer seawater.
This is because as soon as the ice melts, freshwater is washed away and replaced by warmer seawater.
研究者は「広範囲に膨大な海水が入り込むこの過程は、南極大陸からの海面上昇の予測を増大させるだろう」と語る
”This process, which introduces vast amounts of seawater over a wide area, will increase the predicted sea level rise from Antarctica,” the researchers say.
”This process, which introduces vast amounts of seawater over a wide area, will increase the predicted sea level rise from Antarctica,” the researchers say.