Abstract: Low-frequency spaceborne synthetic aperture radar (SAR) systems are susceptive to the equatorial ionospheric scintillation effects. The scintillation amplitude stripes induced by ionospheric irregularities have been frequently observed in numerous equatorial nighttime acquisitions of the Advanced Land Observing Satellite (ALOS) Phased Array-type L-band Synthetic Aperture Radar (PALSAR). This kind of artifact is negative to SAR imaging and interferometry, but provide a new technique for equatorial ionospheric scintillation observation. A methodology that extracts amplitude stripes from the contaminated SAR images via normalized subband processing and orientational filtering (NSB-OF) and measures scintillation parameters is proposed in this paper. NSB processing is to suppress ground scatter and sharpen amplitude stripes. 2D fluctuations induced by amplitude scintillation are separated from ground scatter. Ionospheric scintillation parameters, including scintillation strength <italic>C_kL</italic>, spectrum index <italic>p</italic>, and scintillation index <italic>S₄</italic>, are finally measured via spectrum density function estimation and fitting. A group of PALSAR observations of South American acquisitions suffering amplitude stripes is applied, and the effectiveness of the proposed method is validated by integrating ionospheric ionograms with two-dimensional total electron content distributions, and the results show superiority to the existent non-normalized method on both precision and spatial resolution.