Warming up GEE scripts:

 

Selecting Google-Earth-Engine basic functions and study cases for  Online Training. More information about When & How-To coming soon.

function AddBand_NDWI(image) {
  var ndwi = image.normalizedDifference(['B2', 'B12']).rename('ndwi') // Blue-SWIR
            .clip(Ebro);
         
  return image.addBands([ndwi]);
}

function OverThreshold(image) {
  var F1=image.gte(WetThreshold);
  var F2=image.mask(F1);
  
  return F2;
  
}