if (np.where(refData > thresholdArray[-1], True, False)).any():
            contourRef = ax2.contour(S, L, np.transpose(refData), levels=thresholdArray[:-1], linewidths=2, colors=colorsP)
            # generate corresponding labels
            labels = [str(level) for level in thresholdArray[:-1]]
            # add legend associated to the contour plot