Envisat images

March 1, 2007 5:10 AM

The Envisat ENVIronmental SATellite is on its fifth year in orbit. To celebrate, ESA has assembled four galleries with selected images from the 500 tearabytes of data that has been collected to date. The pictures are of very different types, covering a wide variety of information, for example clorophyll concentration, global wave height, and an interferogram of the Bam earthquake. I personally think the ‘maximum water vapour mean’, in the atmosphere gallery is beautiful. Unfortunately the galleries are in flash so you cannot save the pics directly.
posted by Catfry (12 comments total)

This is neat. That earthquake thing is incredible, but what are they interferogramming there?
posted by DU at 5:50 AM on March 1, 2007

Okay, DU I'm no expert but I think it isn't actually the earthquake itself the image represents but rather the deformation of the surface post-earthquake. So they had a image of the area before and after, and they made the interferogram from those.
posted by Catfry at 6:02 AM on March 1, 2007

When I say 'image' i mean a SAR generated because obviously the interferogram shows height variety.
posted by Catfry at 6:04 AM on March 1, 2007

OK, so it's height. That's very interesting that the wave is so obvious afterwards (and also that they can measure the height so precisely from space).
posted by DU at 6:21 AM on March 1, 2007

Yeah, those images were made using radar. With radar waves you can distinguish distances with tens of centimetres accuracy.
posted by Catfry at 6:41 AM on March 1, 2007

Given the distance from the epicenter, I was imagining the height difference to be more on the order of millimeters. Does the ground really end up 1/4-1/2 meter higher or lower several hundred miles away after an earthquake?
posted by DU at 7:07 AM on March 1, 2007

Great, another reason to skip class.
posted by desjardins at 7:54 AM on March 1, 2007

Weeeelll. I don't know. The problem is they haven't really given much of a description alongside the images. That would have been nice.
Ok.
I found this. Click on 'natural disasters'. Pretty technical but they actually write about millimeter precision so it sounds like you are right.
posted by Catfry at 7:56 AM on March 1, 2007

Lesson: Don't listen to random strangers on the internet. They don't know what they are talking about.
posted by Catfry at 7:57 AM on March 1, 2007

False-color images are always neat to look at. There must be some amount of artistry involved in picking how to map the range (of wavelength, intensity, O2 levels, height, or what have ye) to colors in the visible spectrum. Probably one of the funnest tasks in data collection and analysis.
posted by lostburner at 9:06 AM on March 1, 2007

This is pretty astounding. I was just reading about the Siberian tundra melt and it was described as like "pot holes on a road" and here is the image of it. BTW this tundra melt thing has the potential to create serious run-away global warming as it is methane, not carbon, being released on a massive scale - happening now today. The Russian scientists studying it are freaked out and sending desperate please to the world. The methane is bubbling up so fast the water can't freeze in the winter. Anyway, material for a future FPP, which will include this link to Envisat.
posted by stbalbach at 10:02 AM on March 1, 2007

I digged some more. Turns out you can find alot of the images from the anniversary gallery in this database. In high res and downloadable. stbalbach if you search 'peat bogs' there you get the image in much higher resolution.
posted by Catfry at 10:36 AM on March 1, 2007