Nonparametric detection of cloudy pixels in AVHRR NDVI data
Two nonparametric detectors, based on the Sign Test and the Wilcoxon Signed Rank Test, were applied to 10-day composites of Normalized Difference Vegetation Index (NDVI) data to detect cloud contaminated pixels. The performances of these detectors were found to be no better than a detector based on randomly chosen thresholds. The detector thresholds need to account for the climatologically induced biases in the data for each region and time period every year.