Seasonal Response of Grasslands to Climate Change Figure 10. Correlations of monthly temperatures (left) and precipitation (right) with vegetation activity during the green-up phase (as measured by the NDVI) on the Tibetan Plateau, according to Partial Least Squares (PLS) regression. For each variable, pixels for which the variable-importance-in-the-projection score was,0.8 are shown in gray. Pixels with insufficient data for PLS analysis are shown in white. doi:10.1371/journal.pone.0049230.g010 PLOS ONE | www.plosone.org 11 November 2012 | Volume 7 | Issue 11 | e49230