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Why Is It So Difficult to Map the Ocean?

nautil.us

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Re: Why Is It So Difficult to Map the Ocean?

#41

Post by xjay »

Somewhat related: Earth Gravity Map, GOCE, European Space Agency (ESA)

Visualized: https://www.youtube.com/watch?v=d4E5T9PSbo0

> ESA's Earth Explorer GOCE mission was dedicated to map Earth's gravity with unrivalled precision and provided the most accurate model of the 'geoid' ever produced to further our understanding of how Earth works. After more than four years in orbit, the mission came to a natural end on 11 November 2013, but the wealth of data from GOCE continues to be exploited to improve our understanding of ocean circulation, sea level, ice dynamics, Earth’s interior and climate change.

GOCE: https://www.esa.int/Applications/Observing_the_Earth/FutureE...

Re: Why Is It So Difficult to Map the Ocean?

#44

Post by wolverine876 »

dylan604 wrote: post #36
gleglegle wrote: post #34

Earlier quoted context omitted.

10,000 autonomous ships to do it in 9yrs?

with what funding for that many ships for what purpose of recovering the investment?

Sometimes purpose isn't about money. Though funding would be an issue.

Re: Why Is It So Difficult to Map the Ocean?

#45

Post by dragonwriter »

runeofdoom wrote: post #12
nabla9 wrote: post #10

Earlier quoted context omitted.

Still not good enough. US Navy subs have underwater collisions from time to time. In 2015 USS San Francisco collided underwater sea mount at full speed. It was supposed to be deep blue sea. In 2021 USS Connecticut collided with underwater mountain in South China Sea. US Navy needs to map ocean floor only to 500 meters to keep it safe for submarines but they can't even do that.

Were the collisions due to mapping error or human error? Afaik, the USN hasn't said.

Human error in both cases, though both involved incomplete charts (the ridge the Connecticut hit was uncharted but there were all kinds of command/procedure errors that contributed to hitting it [and a number of significant command/procedure problems involving the ship in the months prior to the collision], the seamount the San Francisco hit in 2005 was marked as a possible hazard on charts the crew had but not the one used for navigation and the notation wasn't transferred to the charts used for navigation.)

Re: Why Is It So Difficult to Map the Ocean?

#46

Post by TheCleric »

dragonwriter wrote: post #32
nabla9 wrote: post #10

Earlier quoted context omitted.

Still not good enough. US Navy subs have underwater collisions from time to time. In 2015 USS San Francisco collided underwater sea mount at full speed. It was supposed to be deep blue sea. In 2021 USS Connecticut collided with underwater mountain in South China Sea. US Navy needs to map ocean floor only to 500 meters to keep it safe for submarines but they can't even do that.

> In 2015 USS San Francisco collided underwater sea mount at full speed. It was supposed to be deep blue sea. First, it was 2005, not 2015. Second, the seamount they struck was marked on charts the crew had as a potential hazard, they failed to review those charts and transfer the notation to the chart used for navigation. > In 2021 USS Connecticut collided with underwater mountain in South China Sea. And not long be…

Had the pier been mapped? ;)

Re: Why Is It So Difficult to Map the Ocean?

#48

Post by emmelaich »

dylan604 wrote: post #11
emmelaich wrote: post #7

Earlier quoted context omitted.

You can use laser, but that's only good for up to around 50m deep. https://www.dst.defence.gov.au/innovation/laser-airborne-dep...

that's not very useful for the task then is it? maybe along shorelines, but that's not what needs mapping since it's already been covered in details.

Right, not so much for purposes mentioned in the article, but still valuable for reefs and navigation.

Re: Why Is It So Difficult to Map the Ocean?

#49

Post by wholinator2 »

dylan604 wrote: post #37
hoyd wrote: post #19

"Everything about the seafloor is bigger, bolder, and more extreme than the comparatively quiet terrain we know as land." Well said :-)

Why is that, when it's just land covered in water

Land covered in miles of water. A distance which would crush you into jello many times over. A human body would be disintegrated. There's no light, the temperature is right around freezing, the pressure is around 500 atm.

Re: Why Is It So Difficult to Map the Ocean?

#50

Post by sn00tz00t »

bradrn wrote: post #30

I do research on oceanic lidar. The basic problem is that light is absorbed and scattered by water, to a far greater extent than it is by air. Thus, even though we have no problem seeing through hundreds of kilometres of air, even a kilometre of water is sufficient to filter out nearly all light [0]. In practical terms, this restricts the ability of lidar systems to detect features underwater. As a general rule of th…

how are bathymetric maps made? if i go to google maps i can see the ocean floor in low res - is that done by satellites?

i remember trying to find data of a particular area (near azores) using NOAA maps and all i found was some sort of compendium maps made by different vessels across the years mashed together in a hodge podge of resolutions

life sounds rough for ocean floor researchers lmao

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