Soil moisture mapping using Sentinel-1-Data and SNAP?

Hello everyone, does anyone of you know how to use Sentinel-1-Data to map soil moisture? I know that there are many algorithms like SMOSAR or Multi-temporal Bayesian. But what are the basic steps I schould follow? What would be the best toolbox (s1tbx, s2tbx, s3tbx) / method / software (e.g. PolSARpro) which is helpful?

Thank you for your efforts!

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I think that there is no general approach which could be applied. Of course, SAR backscatter intensity is influenced by soil moisture. But it is also influenced by roughness and shape of the surface. So according to my understanding at least two things are necessary for soil moisture mapping:

  1. Multi-temporal data: You can not retrieve soil moisture by a single image. Variation in SAR backscatter over a longer time (at best between rainy and dry seasons) gives you the variation which can be expected.

  2. Field data: There is no general mathematical relationship between SAR backscatter and soil moisture. It strongly depends on the properties of the ground, the climatic setting and the mode and resolution of the sensor. I would highly disadvise from adopting regressions from studies which claim to have found this relationship, because it is strongly limited on their geographical and temporal conditions. Only when you collect own measurements at your study sites you can correlate it to your SAR images.

There is a reason that operational soil moisture retrieval is currently limited to a resolution of 500 m or 1 km.


Hello ABraun, many thanks for your reply. This is not as easy as one might have thought. But it makes sense because there are still too many variables and dependencies. Therefore I need to use continuous measurements and field data for a good result.
Thank you very much.

@ABraun I recently attended an ARSET webinar where the host performed SME , saw a soil moisture toolbox in SNAP under the tab Radar>> soilmoisture(see image attached). I have the full toolbox installed but my installation does’nt contain the same. Where do you suggest I find the same?

FYI: corresponding webinar slides can be found here :


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I have never seen this toolbox, sorry. Can you please post a link to the tutorial?
Could be a custom external tool.

did you find how to get the soil moisture toolbox in SNAP

you have to download the SMOS Toolbox or
or use All Toolboxes here

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Can use the methodology to extract soil moisture from sentinel 1 as the one that was used in this webinar from Radarsat-2 data

I don’t think so.

Is it due to the fully polarimetric in Radarsat 2?

Not without any data from the field, nor in any standardized way.
Have a look at some studies:

I am also really interested in soil moisture. Has anyone come up with a good recipe for this yet? I would love to try it out and provide feedback and share my findings.

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The workflow in the webinar mentioned above looks promising, but it misses the most interesting step of “SM-Dielectric Modeling”


This was from something developed for AAFC. Unfortunately, we may need to redevelop it from scratch in order to open source it.



I contacted with AAFC and request soil moistures tool and finally, Heather McNairn and Jiao Xianfeng sends a link, SNAP with soil moisture tools. I’m want to give you a link to download the file with their permission.

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mcarslanoglu what the link you given it is not opening for soil moisture tool in SNAP, how you approached them, can you please help me.
thanks in advance

open it via a FTP client, such as filezilla:

Hello sir!
i have a ground data of soil moisture .now i want to calculate soil moisture from SAR …so what i do…please help me!

Could you explain how to download please?.

Thank you

I know that. Copy and paste in crome or any navigator.