Optimal Estimate of Global Biome—Specific Parameter Settings to Reconstruct NDVI Time Series with the Harmonic ANalysis of Time Series (HANTS) Method

Terrestrial remote sensing data products retrieved from radiometric measurements in the optical and thermal infrared spectrum such as vegetation spectral indices can be heavily contaminated by atmospheric conditions, including cloud aerosol layers. This contamination results gaps or noisy observations. The harmonic analysis of time series (HANTS) has been widely used for reconstruction imagery recent decades. To use HANTS model, a parameters, number frequencies (NF), fitting error tolerance (FET), degree over-determinedness (DoD), regularization factor (Delta), need to defined users. These parameters provide flexibilities, but also make it difficult non-expert users determine appropriate settings specific applications. study systematically evaluated performance model under different parameter setting scenarios simulating pixel-wise reference NDVI series. these numerical experiments were further identify optimal improve global performance. suggested areas (local optimization). If user opts unique reconstruction, NF = 4, FET 0.05, DoD 5, Delta 0.5 produce best across all (global In addition, several internal improvements, dynamic weighting scheme, polynomial inter-annual components, ancillary attributes input reconstruction. With results, future easily applications regions.