Data blending of MODIS and Landsat, spectral/temporal information from MODIS and spectral/spatial context from Landsat. Nice way to increase temporal density at a high resolution (Landsat, 30m). Please find here some refs from the initial paper by Gao (STAR-FM), a proof-of-concept on real data (Hilker) and a change detection addition to the data blending approach (Hilker, STAARCH. For more options, search under the name of the original algorithm and you will find many more options.
Article On the Blending of the Landsat and MODIS Surface Reflectance...
Article Generation of dense time series synthetic Landsat data throu...
Article A new data fusion model for high spatial- and temporal-resol...