地球上近四分之一的海底現在被繪製成地圖

2個月前
地球上近四分之一的海底現在被繪製成地圖

據認為,還有10-15%的信息仍被藏在服務器上,部分原因是業主擔心如果他們公開這些信息,可能會泄露商業或國防機密。

"我們試圖傳達的信息之一是,我們不需要高分辨率的數據。高分辨率是好的;我們可以用它來工作。但低分辨率是完全可以接受的。

此外,崎嶇的海底影響着洋流的行為和水的垂直混合。這是改進預測未來氣候變化的模型所需要的信息--因為正是海洋在地球上移動熱量方面起着關鍵的作用。

目前,我們對地球四分之三以上的水下地形的了解僅僅來自於低分辨率的衛星測量,通過這些特徵對海面的引力影響,推斷出高大的海山和深谷的存在。水在大型海底山的質量上堆積,在有海溝的地方略微傾斜。

由日本財團資助的 "海底2030 "正在鼓勵任何遠離陸地的人打開他們的聲納設備,進行深度探測。而且這不僅僅是大船的測量,裝有數據記錄器的小型遠洋遊艇也可以做出貢獻。

Seabed 2030的明星之一是美國冒險家Victor Vescovo。這位德克薩斯州的金融家正在使用一個潛水器訪問世界上最深的地方,但他所到之處,他的支持船都會打開回聲測深儀。

"我們不是一個商業機構,所以我們不需要遵循最省油的路線。當我們去探險時,我們會問[海底2030],'你的優先領域是什麼? ';然後我們會轉移一點注意力來覆蓋這些地區。"

然而,很明顯,要接近獲得地球海底形狀的全貌,需要在方法和能力上有一個步驟的改變。世界上的許多地方是如此的遙遠,很少有船會訪問它們,更不用說在這些地區獲取深度數據了。

從本頁頂部的地圖中的一行數據中可以看到這將如何運作的一瞥。它是由Saildrone Surveyor去年在舊金山和檀香山之間的一次巡航中收集的。


It's thought a further 10-15% is still squirrelled away on servers, in part because the owners worry they might be giving away commercial or defence secrets if they release the information.

"One of the messages we're trying to get across is that we don't require high-resolution data. Hi-res is nice; we can work with it. But lower resolution is perfectly acceptable.

In addition, the rugged seafloor influences the behaviour of ocean currents and the vertical mixing of water. This is information required to improve the models that forecast future climate change - because it is the oceans that play a pivotal role in moving heat around the planet.

At the moment, our knowledge of just over three-quarters of the planet's underwater terrain comes only from low-resolution satellite measurements that have inferred the presence of tall seamounts and deep valleys from the gravitational influence these features have on the sea surface. Water piles up over the mass of a large submarine mountain and dips slightly where there is a trench.

Seabed 2030, which is funded by Japan's Nippon Foundation, is encouraging anyone who ventures away from the land to switch on their sonar equipment and take depth soundings. And this isn't just about measurements from big ships; small ocean-going yachts fitted with data loggers can also make a contribution.

One of Seabed 2030's stars is the American adventurer Victor Vescovo. The Texan financier is using a submersible to visit the deepest places in the world's oceans, but everywhere he goes his support ship switches on its echosounder.

"We're not a commercial outfit so we don't have to follow the most fuel-efficient routes. When we go on an expedition we ask [Seabed 2030], 'what are your priority areas?'; and we divert a little bit to cover those areas."

It's clear, however, that to come close to obtaining a full picture of the shape of Earth's ocean bottom, there will need to be a step change in approach and capability. Many parts of the world are so remote, few ships will visit them, let alone acquire depth data in those regions.

There is a glimpse of how this will work in one line of data featured in the map at the top of this page. It was gathered by the Saildrone Surveyor on a cruise between San Francisco and Honolulu last year.

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