Copernicus Browser pre-calculated Sentinel 2 band indices useful for desertic regions

Continuing with this series of the naive photo-interpreter using Copernicus Browser, another interesting feature is the presence of many pre-calculated indices.

Considering geology and arid zones, a few useful pre-calculated indices are SWIR (Short-Wave Infrared Composite, bands B12, 8A and 4) and False Color (Urban, B12, 11 and 4). 

The shown examples come from the South-Eastern Libyan desert, almost to the boundary with Egypt.

As you can see, the natural color image does not evidence particular lithological differences within the outcropping structure surrounded by sands. 

 

 

Using the SWIR index, lithological boundaries and contacts are much more evident and can be used to draft a first preliminary geological interpretation, where there are volcanic and possibly sedimentary rocks.

 

 Also False Color (Urban), using bands B12, 11 and 4 differentiate between lithologies. 

 

 

Considering instead the different types of sands, NDSI (Normalised Difference Snow Index, bands  3, 11, 4 and 2) is particularly useful: the 'rivers' of younger and brighter sands around the older sand deposits are clearly evident.

 

 

Time series of NDVI within ROI with Copernicus Browser

 

The Copernicus Browser allows also to calculate time series for specific indices, for instance NDVI, by just drawing a ROI region with the pen or rectangle tool (see rectangle in image) and using the Statistical Info button.

 

The NDVI values are quite high in the last year, since this land plot is grassland, periodically cut for animal feed. It is possible to see the NDVI variations up to 5 years.

 

Timelapses creation within Copernicus Browser

Following this video: Introduction to the CDSE website and Copernicus Browser I learned that the Copernicus Browser allows to directly create timelapses animations from Sentinel data.

I tried with NDWI, that indicates the humidity degree of the surfaces, in a zone of the Piemonte (Italy) region, where I currently live. The Po river is the major river of this zone.

I set the parameters as in the image below: 

 and after a few minutes of tile selections, the following timelapse animation was created:

 

 

It's not clear to me why the final frames number is quite low, having set a 2016 to 2025 analysis interval with steps of 1 day. 

Apart from that, the result is interesting, since it potentially allows for temporal analysis of natural variations without any major effort.