Hi everybody,
which channel of radar data is suitable for estimating of forest parameters? for example, I used HH channel for estimating CHM. what difference is between HH and HV and VV?
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While HH and VV are waves that are horizontally/vertically transmitted received by the sensor, the cross-polarization channels (VH and HV) are the proportion of the signal that changes its polarization before it is received, mostly because of the objects at the earth’s surface that interact with this wave. This is often the case for vegetation bodies with voluminous structures.
It is often reported that backscatter intensity of VH and VH is more sensitive to vegetation.
I recommend the resources of the EO College on polarimetry: https://eo-college.org/resources/polsar/
Further good resources: Single vs. Multi-Polarization SAR data
Introduction to radar remote sensing for vegetation monitoring and mapping
Regarding the canopy height model you mention: Many approaches use radar interferometry which is not using the backscatter intensity but the phase information of the wave which is present in the complex signal of SLC data. To my understanding, using HH or VV is the most suitable approach here. As reported here (slide 9), VH or HV result in lower coherence, which reduces the quality of interferometric products.
In this context, this might also help you: Using VV and VH to make DEM
I compared the polarization of an image pair regarding its suitability for interferometric analysis: Effect of polarization on interferometric products
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Dear Andreas…
Your comment is:
It is often reported that backscatter intensity of VH and VH is more sensitive to vegetation.
Did you mean VH and HV?
yes, sorry. The cross-polarized channels HV and VH.