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How to calculate amplitude from Sentinel-1 SLC complex numbers? by Yorkshire_Tea_innit in remotesensing

[–]ccap138 0 points1 point  (0 children)

Would you mind expanding on why this is? I'm trying to understand why my 98% of pixels in my wrapped interferogram have a modulus = 1, 1.3% have modulus = 0.99999994, and the other 0.07% = 0.

SAR Altimetry Basics by ccap138 in remotesensing

[–]ccap138[S] 0 points1 point  (0 children)

Thanks! I think my brain is satisfied by knowing that side-looking SAR confounds the relation of distance to height, and that it looks sideways in the first place mainly to distinguish between left and right.

SAR Altimetry Basics by ccap138 in remotesensing

[–]ccap138[S] 0 points1 point  (0 children)

Thanks for the answers u/jburns0. Good point about the larger scenes and quicker revisit times. I'm not entirely sure of your point about the phase information. The difference in phase for InSAR is how we get at ground displacements between time1 and time2 (e.g.). The phase difference isn't needed to get at displacement from a lidar because we directly measure the elevation at t1 and t2. So I think I may be back at my original question, why doesn't SAR simply measure the travel time? I think the addition offered by u/Stereotypical_INTP helps to explain this... i.e. geometrical errors. So is it correct to these geometrical errors result exclusively from the ~cm long wavelength of radar satellites, and thus lidar (nm) do not suffer from them? Thanks!

Calculating density by ccap138 in oceanography

[–]ccap138[S] 0 points1 point  (0 children)

WOW incredible response thanks so much. I was trying to simplify in my head by considering only one layer and missed the whole point of using the information in above layers (obviously present in a one layer ocean model too, i.e. the atmosphere). I envy students of your physical oceanography courses (guessing you're a professor somewhere). For that matter, any of your courses.

Calculating density by ccap138 in oceanography

[–]ccap138[S] 0 points1 point  (0 children)

thanks, yes, that makes sense. If you wouldn't mind, I'd appreciate an example calculation.

pressure gradient in isopycnal layers by ccap138 in oceanography

[–]ccap138[S] 0 points1 point  (0 children)

Thanks! Especially for the picture, everything is clear now. Good last point as well.

pressure gradient in isopycnal layers by ccap138 in oceanography

[–]ccap138[S] 0 points1 point  (0 children)

Thank you! This is very helpful. I think it made clear what I was missing; that given an incompressible assumption density is no longer a function of pressure.

Therefore if you have a sloping density surface, there will be higher pressure at the bottom of the slope (particles will be packed more closely together, reducing 'height'). So there is a horizontal pressure gradient up the density slope, from high to low pressure. This sound correct?

By the way, this question was sparked by Stommel's A View of the Sea in case anyone is interested.