Increasing value of displacement with increase height

[ABraun]

How to mask out pixels is described here:

Subsidence map in 3d view

I explained it in the post above. Just entering the coherence is not a valid logical expression. In this field (valid pixel expression) you define at which locations your result is usable. As coherence is a measure for quality of the interferometric product you only want those pixels at a location where the coherence is larger than a threshold, let’s say 0.4. Thus, just putting the coherence there is pointless because the expression is lacking a condition. Enter this instead: coh_23Nov2012_08…

Of course you need the long temporal baseline in order to observe changes. But the coherence won’t be high over the full image.
Regarding the atmospheric content: Maybe you have the chance to investigate another image pair within a similar period. If it contains the same ramping as your example above, it is probably caused by the topographic phase removal (did you use the 1Arc Sec SRTM instead of the 3Sec?). If it is different atmospheric effects dominate in the distortion of your displacement values and you could have more success with another image pair.