Determination of scaling characteristics of AVHRR data with wavelets: application to SGP97

A wavelet multi-resolution analysis was conducted using vegetation and radiometric temperature data derived from the Advanced Very High Resolution Radiometer (AVHRR) data from the Southern Great Plains 1997 (SGP97) Hydrology Experiment. The wavelet coefficients were used to investigate whether the Normalized Difference Vegetation Index (NDVI) and radiometric temperature fields exhibit self-similar scaling behaviour. Using the first six moments of the wavelet coefficients through eight levels of dyadic decomposition, the NDVI data are shown to be statistically self-similar with a slope of approximately -0.72 in each of the horizontal, vertical, and diagonal directions of the image over scales ranging from 2000 to 256 000 m. The radiometric temperature data are also shown to exhibit self-similarity with slopes ranging from -0.9 in the diagonal direction to -1.0 in the vertical direction over the same scales. These slopes indicate long range behaviour and may imply a methodology for statistically assimilating remotely sensed data into large-scale meso and global climate models.