Left: means computed over the active growing season for a) FPET, (b) NDVI, (c) NDII, and (d) fractional “root-zone” soil moisture (RZM, in the top 1 m layer) from MERRA-2 (all quantities are dimensionless); Right: corresponding standard deviation of their weekly IAV (panels e–h). White areas with no data correspond to large deserts such as the Sahara, Arabian, and Gobi deserts.