11–20 of 36 posts
Technical SAR question: Is the sea surface removed post-hoc, or does the sea not reflect these radar waves in a sufficient amount to show up? I seem to remember NISAR [1] will map land and ice - so presumably water ice shows up. I ask b/c if they are synthetically removing the sea surface at 1-5m resolution that seems really hard given tides, waves, etc. 1. https://en.wikipedia.org/wiki/NISAR_(satellite)
Technical SAR question: Is the sea surface removed post-hoc, or does the sea not reflect these radar waves in a sufficient amount to show up? I seem to remember NISAR [1] will map land and ice - so presumably water ice shows up. I ask b/c if they are synthetically removing the sea surface at 1-5m resolution that seems really hard given tides, waves, etc. 1. https://en.wikipedia.org/wiki/NISAR_(satellite)
Technical SAR question: Is the sea surface removed post-hoc, or does the sea not reflect these radar waves in a sufficient amount to show up? I seem to remember NISAR [1] will map land and ice - so presumably water ice shows up. I ask b/c if they are synthetically removing the sea surface at 1-5m resolution that seems really hard given tides, waves, etc. 1. https://en.wikipedia.org/wiki/NISAR_(satellite)
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I wonder at what density of wind farms they begin to interfere with each other's generating capacity. Presumably within one farm the turbines are sufficiently spaced that the reduction in power is minimal, but how large can an individual one get? Or is the amount of energy they take out of the wind negligable?
I am curious how much small elevation differences impact optimal positioning of turbines, as that is a non-issue with offshore wind. The turbines in land-based wind farms are not in a nice grid like the offshore wind farm. https://openinframap.org/#9.68/41.6112/-92.4971
The excerpt from an abstract below mentions the wake turbulence can cause other turbines to shut down.
"...The distance between the turbines is among other things dependent on the recovery of wind energy behind the neighboring turbines and the increased wind load. Models for the mean wind speed and turbulence intensity in wind turbine parks are considered with emphasis on modeling the spatial correlation. Representative limit state equations for structural failure of wind turbine towers are formulated. The probability of failure is determined taking into account that wind turbines are parked for wind speeds larger than 25 m/s resulting in reduced wind loads. An illustrative example is presented where illustrative models for the spatial correlation is taken into account"
https://www.tandfonline.com/doi/full/10.1080/102866006011566...
Technical SAR question: Is the sea surface removed post-hoc, or does the sea not reflect these radar waves in a sufficient amount to show up? I seem to remember NISAR [1] will map land and ice - so presumably water ice shows up. I ask b/c if they are synthetically removing the sea surface at 1-5m resolution that seems really hard given tides, waves, etc. 1. https://en.wikipedia.org/wiki/NISAR_(satellite)
The liquid water absorbs most of the radar wave (at least for the C band, as is the case of sentinel-1). Thus, in the images it appears natively "black". When there are a lot of waves, the surface of the water forms some spurious reflectors that appear as a light texture in the surface, but the signal is definitely less powerful than metal/concrete reflectors of buildings and ships. Notice that in the "Humber" image…
Technical SAR question: Is the sea surface removed post-hoc, or does the sea not reflect these radar waves in a sufficient amount to show up? I seem to remember NISAR [1] will map land and ice - so presumably water ice shows up. I ask b/c if they are synthetically removing the sea surface at 1-5m resolution that seems really hard given tides, waves, etc. 1. https://en.wikipedia.org/wiki/NISAR_(satellite)
Images collected at lower incidence (closer to nadir) might feature very bright surface water if it is calm, as more energy is reflected towards the radar.
Rough water surface is a diffuse scatterer, and will generally appear brighter than calm waters.
I had no idea shipping lanes were so densely populated. EDIT - thanks all. I'll read it next time ...
I wonder at what density of wind farms they begin to interfere with each other's generating capacity. Presumably within one farm the turbines are sufficiently spaced that the reduction in power is minimal, but how large can an individual one get? Or is the amount of energy they take out of the wind negligable?
I wonder at what density of wind farms they begin to interfere with each other's generating capacity. Presumably within one farm the turbines are sufficiently spaced that the reduction in power is minimal, but how large can an individual one get? Or is the amount of energy they take out of the wind negligable?
I read that a rule of thumb was 4-5 diameter widths between turbines at right angles to prevailing wind and then 7 diameter widths between rows facing the wind
Technical SAR question: Is the sea surface removed post-hoc, or does the sea not reflect these radar waves in a sufficient amount to show up? I seem to remember NISAR [1] will map land and ice - so presumably water ice shows up. I ask b/c if they are synthetically removing the sea surface at 1-5m resolution that seems really hard given tides, waves, etc. 1. https://en.wikipedia.org/wiki/NISAR_(satellite)