To identify the changes of green-up dates on the Tibetan Plateau during the last decade, ITP scientists engaged tremendous efforts, for example, by using Normalized DifferenceVegetation Index (NDVI) data derived from Moderate Resolution Imaging Spectroradiometer (MODIS) and SystèmePour l’Observation de la Terre (SPOT). Their study found no evidence of continuously advanced green-up dates in the Tibetan Plateau over the last decade. This conclusion updated previous study that revealed continuous advance of the green-up dates during 1982-2011, which they thought was misled by “not correcting for the increased non-growing season NDVI”.

For the Tibetan Plateau where multi-sphere interactions are active yet continuous field observation is lacking, cautions should be exerted against depending solely on satellite-derived phenology. They proposed.

“…greenness vegetation indices are easily contaminated by adverse meteorological conditions and other factors, such as background changes, in particular during the green-up times when the signal from vegetation is weak.” They said.

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