5 ms·

Fleets of radar satellites are measuring movements on Earth like never before

90 points by sohkamyung 6y ago

pmar 6y ago
What a mediocre piece... Random walk among whatever quotes author could find....
Zenst 6y ago
I wonder if this will for some area's of science be a step like going from seeing the surface of your skin and then suddenly seeing it under a microscope and initially being shocked at what you see.
- NortySpock 6y ago
  Maybe it will be like "The Core" (2003 box office failure) and we discover Earth is dying way faster than expected, then we have to send a squad of heroes to...
cozzyd 6y ago
Are we going to get a public DEM dataset better than SRTMv3 any time soon?
- alleycat5000 6y ago
  Already available: https://copernicus-dem-30m.s3.amazonaws.com/readme.html https://copernicus-dem-30m.s3.amazonaws.com/readme.html
  - thatcherc 6y ago
    Pretty cool! Looks like this has the same resolution 30 meter resolution as the global SRTM DEM, but with coverage of the whole globe. Looking forward to using this.
    - cozzyd 6y ago
      to be fair, between SRTM, ArcticDEM and REMA, you could get all but maybe some southern islands already?
- sstanie 6y ago
  Hopefully the DLR will release the TanDEM-X dataset at some point in the future. https://en.wikipedia.org/wiki/TanDEM-X https://en.wikipedia.org/wiki/TanDEM-X It could be the best global DEM if it's released, but now they're still charging for it. Maybe in a few years as new DLR satellites come on line.
TeMPOraL 6y ago
I understand the radar doesn't penetrate water much, is that correct? I worry whether this could be used to detect submarines from orbit - which would be very dangerous, as it could instantly break MAD, which currently hinges on submarines.
- tony_cannistra 6y ago
  That's correct. However, SAR is used to detect vessels on the surface all the time. It's actually been used to discover vessels that are illegally fishing. https://globalfishingwatch.org/impacts/illegal-fishing-northwest-indian-ocean/ https://globalfishingwatch.org/impacts/illegal-fishing-north...
  - nomel 6y ago
    At this point, my naive assumption is that all vehicles, boats, planes, and humans with a cellphone are tracked at all times, by someone.
  - notahacker 6y ago
    An interesting, and successful regulatory use is detecting oil slicks from bilge dumping (and the vessel associated with them) Example: https://skytruth.org/2019/11/multiple-accounts-of-oily-pollution-found-in-the-mediterranean-sea/ https://skytruth.org/2019/11/multiple-accounts-of-oily-pollu...
- lambda_obrien 6y ago
  Submarines are first strike tools, that's kind of anti-MAD, so it would be great if they were rendered useless.
  - elefanten 6y ago
    You can initiate effective first strikes with submarines, but they provide no counter to MAD. They're not anti-MAD in any sense -- destruction would still be mutual. And one of the most assured scenarios of destruction is enemy submarines striking back, even if the other legs of nuclear forces are successfully taken out. Submarines are the hardest to take out, so they are the most pro-MAD.
angst_ridden 6y ago
Using radar interferometry, you can get very high-resolution altitude and surface shift detection. I knew the researcher who was doing the synthetic aperture radar back in the 80s starting with SeaSat data, and he was getting very detailed elevation maps and earthquake change maps. He was also measuring glacial flow. Funny that the author of the piece doesn't mention the principal researcher on that project at JPL (and she happens to the same last name as one of the other JPL researchers). Anyway, I can only imagine that this technology's gotten a whole lot cheaper now.
- deleted 6y ago
  [deleted]
01100011 6y ago
Can you get this sort of data publicly? I've been watching the Mina, NV earthquake storm(https://earthquake.usgs.gov/earthquakes/map/?extent=37.25766,-119.21814&extent=38.80761,-116.19141&range=month&listOnlyShown=true&baseLayer=terrain&settings=true https://earthquake.usgs.gov/earthquakes/map/?extent=37.25766...) over the last year and I'm curious how the ground is moving in response to those quakes.
- sstanie 6y ago
  JPL releases some of their products of earthquakes/disasters world wide here: https://aria-share.jpl.nasa.gov/ https://aria-share.jpl.nasa.gov/ Also a group a Leeds is trying to make a public portal: https://comet.nerc.ac.uk/COMET-LiCS-portal/ https://comet.nerc.ac.uk/COMET-LiCS-portal/ Neither place seems to have the recent Nevada earthquakes though. There's a bunch of effort to make InSAR more available/accessible. Even though plenty of SAR data is available through ASF (https://search.asf.alaska.edu/#/ https://search.asf.alaska.edu/#/), it takes a bunch more processing beyond the SAR images to get useful ground deformation. ASF has also started to try providing some interferograms (single InSAR images) but without averaging a bunch over an area, or doing more advanced stuff, they often look like mostly noise on a given day.
  - ElMono 6y ago
    The following can be used to process InSAR data: https://github.com/isce-framework/isce2 https://github.com/isce-framework/isce2 An update is in progress: https://github.com/isce-framework/isce3 https://github.com/isce-framework/isce3
- ants_a 6y ago
  ESA freely distributes all data acquired by the Sentinel program from here: https://scihub.copernicus.eu/ https://scihub.copernicus.eu/ There are also multiple partner sites with the data, including cloud providers that can you a VM with the data files already mounted. Software is a bit harder, for simple interferograms of two measurements you can just use open source Sentinel-1 toolbox ( https://github.com/senbox-org/s1tbx https://github.com/senbox-org/s1tbx ) to align, diff, subtract geometric corrections based on an elevation model and convert the measurements to geographic coordinates. This will be enough for seeing large scale motion, like earthquakes. For better quality processing you need multi-temporal InSAR which can estimate atmospheric phase delay, height of persistent reflectors which will cause a geometric phase difference due to slight differences in measurement location (measurement baseline). There is some open source software available for this (e.g. StaMPS), but I can't vouch for its capabilities.
supernova87a 6y ago
I would love to hear some perspective on this, but from my recollection one of the most significant early datasets ever released was about 20 years ago when I was in grad school -- I heard about this "Shuttle Radar Topography Mission" that was going to scan the entire Earth. I remember it had a long extendible gantry (?) that was deployed out of the shuttle bay to give it more scanning baseline. I think it was done for the intelligence community (this being just post 9-11) but some part of it became public? I remember reading that the data was collected on tapes (!) that they had to swap hot to ensure continuity of the data. Shortly after that, I noticed that Earth simulation flyby animations became almost common, planes started being equipped with simulated terrain maps for collision warning, etc. I imagine it was a revolution for a lot of industries.
- sstanie 6y ago
  The inspector-gadget arm sticking out of the space shuttle does look pretty funny https://www.usgs.gov/centers/eros/science/usgs-eros-archive-digital-elevation-interferometry-and-srtm-overview?qt-science_center_objects=0#qt-science_center_objects https://www.usgs.gov/centers/eros/science/usgs-eros-archive-... I don't think the arm was related to anything with intelligence- they just needed some way to have a second radar slightly moved away from the main one on the Shuttle. The further away it is, the more accurate they could measure elevation, so they stuck it way out on a pole. But I think you're right that it's possibly one of the most widely used GIS datasets. Some applications obviously need finer resolution than 30 meters, and lidar is more accurate for the small areas that it can cover, but it's still cool that they could cover most of the globe at 30 meter resolution
  - walrus01 6y ago
    The ASTER GDEM data set covers most of the world and is more accurate than non-USA SRTM.
  - ci5er 6y ago
    THEY cover at 10m. You get the low-rez version. Better than the 90m before, so who am I to look a gift horse in the mouth.
Krasnol 6y ago
I wish we could use that for OpenStreetMap mapping :(

90 points by sohkamyung 6y ago

pmar 6y ago

What a mediocre piece... Random walk among whatever quotes author could find....

I wonder if this will for some area's of science be a step like going from seeing the surface of your skin and then suddenly seeing it under a microscope and initially being shocked at what you see.

NortySpock 6y ago
Maybe it will be like "The Core" (2003 box office failure) and we discover Earth is dying way faster than expected, then we have to send a squad of heroes to...

cozzyd 6y ago

Are we going to get a public DEM dataset better than SRTMv3 any time soon?

alleycat5000 6y ago
Already available: https://copernicus-dem-30m.s3.amazonaws.com/readme.html https://copernicus-dem-30m.s3.amazonaws.com/readme.html
- thatcherc 6y ago
  Pretty cool! Looks like this has the same resolution 30 meter resolution as the global SRTM DEM, but with coverage of the whole globe. Looking forward to using this.
  - cozzyd 6y ago
    to be fair, between SRTM, ArcticDEM and REMA, you could get all but maybe some southern islands already?
sstanie 6y ago
Hopefully the DLR will release the TanDEM-X dataset at some point in the future. https://en.wikipedia.org/wiki/TanDEM-X https://en.wikipedia.org/wiki/TanDEM-X It could be the best global DEM if it's released, but now they're still charging for it. Maybe in a few years as new DLR satellites come on line.

TeMPOraL 6y ago

I understand the radar doesn't penetrate water much, is that correct? I worry whether this could be used to detect submarines from orbit - which would be very dangerous, as it could instantly break MAD, which currently hinges on submarines.

tony_cannistra 6y ago
That's correct. However, SAR is used to detect vessels on the surface all the time. It's actually been used to discover vessels that are illegally fishing. https://globalfishingwatch.org/impacts/illegal-fishing-northwest-indian-ocean/ https://globalfishingwatch.org/impacts/illegal-fishing-north...
- nomel 6y ago
  At this point, my naive assumption is that all vehicles, boats, planes, and humans with a cellphone are tracked at all times, by someone.
- notahacker 6y ago
  An interesting, and successful regulatory use is detecting oil slicks from bilge dumping (and the vessel associated with them) Example: https://skytruth.org/2019/11/multiple-accounts-of-oily-pollution-found-in-the-mediterranean-sea/ https://skytruth.org/2019/11/multiple-accounts-of-oily-pollu...
lambda_obrien 6y ago
Submarines are first strike tools, that's kind of anti-MAD, so it would be great if they were rendered useless.
- elefanten 6y ago
  You can initiate effective first strikes with submarines, but they provide no counter to MAD. They're not anti-MAD in any sense -- destruction would still be mutual. And one of the most assured scenarios of destruction is enemy submarines striking back, even if the other legs of nuclear forces are successfully taken out. Submarines are the hardest to take out, so they are the most pro-MAD.

angst_ridden 6y ago

Using radar interferometry, you can get very high-resolution altitude and surface shift detection. I knew the researcher who was doing the synthetic aperture radar back in the 80s starting with SeaSat data, and he was getting very detailed elevation maps and earthquake change maps. He was also measuring glacial flow. Funny that the author of the piece doesn't mention the principal researcher on that project at JPL (and she happens to the same last name as one of the other JPL researchers). Anyway, I can only imagine that this technology's gotten a whole lot cheaper now.

deleted 6y ago
[deleted]

01100011 6y ago

Can you get this sort of data publicly? I've been watching the Mina, NV earthquake storm(https://earthquake.usgs.gov/earthquakes/map/?extent=37.25766,-119.21814&extent=38.80761,-116.19141&range=month&listOnlyShown=true&baseLayer=terrain&settings=true https://earthquake.usgs.gov/earthquakes/map/?extent=37.25766...) over the last year and I'm curious how the ground is moving in response to those quakes.

sstanie 6y ago
JPL releases some of their products of earthquakes/disasters world wide here: https://aria-share.jpl.nasa.gov/ https://aria-share.jpl.nasa.gov/ Also a group a Leeds is trying to make a public portal: https://comet.nerc.ac.uk/COMET-LiCS-portal/ https://comet.nerc.ac.uk/COMET-LiCS-portal/ Neither place seems to have the recent Nevada earthquakes though. There's a bunch of effort to make InSAR more available/accessible. Even though plenty of SAR data is available through ASF (https://search.asf.alaska.edu/#/ https://search.asf.alaska.edu/#/), it takes a bunch more processing beyond the SAR images to get useful ground deformation. ASF has also started to try providing some interferograms (single InSAR images) but without averaging a bunch over an area, or doing more advanced stuff, they often look like mostly noise on a given day.
- ElMono 6y ago
  The following can be used to process InSAR data: https://github.com/isce-framework/isce2 https://github.com/isce-framework/isce2 An update is in progress: https://github.com/isce-framework/isce3 https://github.com/isce-framework/isce3
ants_a 6y ago
ESA freely distributes all data acquired by the Sentinel program from here: https://scihub.copernicus.eu/ https://scihub.copernicus.eu/ There are also multiple partner sites with the data, including cloud providers that can you a VM with the data files already mounted. Software is a bit harder, for simple interferograms of two measurements you can just use open source Sentinel-1 toolbox ( https://github.com/senbox-org/s1tbx https://github.com/senbox-org/s1tbx ) to align, diff, subtract geometric corrections based on an elevation model and convert the measurements to geographic coordinates. This will be enough for seeing large scale motion, like earthquakes. For better quality processing you need multi-temporal InSAR which can estimate atmospheric phase delay, height of persistent reflectors which will cause a geometric phase difference due to slight differences in measurement location (measurement baseline). There is some open source software available for this (e.g. StaMPS), but I can't vouch for its capabilities.

supernova87a 6y ago

I would love to hear some perspective on this, but from my recollection one of the most significant early datasets ever released was about 20 years ago when I was in grad school -- I heard about this "Shuttle Radar Topography Mission" that was going to scan the entire Earth. I remember it had a long extendible gantry (?) that was deployed out of the shuttle bay to give it more scanning baseline. I think it was done for the intelligence community (this being just post 9-11) but some part of it became public? I remember reading that the data was collected on tapes (!) that they had to swap hot to ensure continuity of the data. Shortly after that, I noticed that Earth simulation flyby animations became almost common, planes started being equipped with simulated terrain maps for collision warning, etc. I imagine it was a revolution for a lot of industries.

sstanie 6y ago
The inspector-gadget arm sticking out of the space shuttle does look pretty funny https://www.usgs.gov/centers/eros/science/usgs-eros-archive-digital-elevation-interferometry-and-srtm-overview?qt-science_center_objects=0#qt-science_center_objects https://www.usgs.gov/centers/eros/science/usgs-eros-archive-... I don't think the arm was related to anything with intelligence- they just needed some way to have a second radar slightly moved away from the main one on the Shuttle. The further away it is, the more accurate they could measure elevation, so they stuck it way out on a pole. But I think you're right that it's possibly one of the most widely used GIS datasets. Some applications obviously need finer resolution than 30 meters, and lidar is more accurate for the small areas that it can cover, but it's still cool that they could cover most of the globe at 30 meter resolution
- walrus01 6y ago
  The ASTER GDEM data set covers most of the world and is more accurate than non-USA SRTM.
- ci5er 6y ago
  THEY cover at 10m. You get the low-rez version. Better than the 90m before, so who am I to look a gift horse in the mouth.

Krasnol 6y ago

I wish we could use that for OpenStreetMap mapping :(