Reply to comment by M. Lanfredi et al. to “Variations in northern vegetation activity inferred from satellite data of vegetation index during 1981 to 1999” by L. Zhou et al.

[1] In their paper, Lanfredi et al. [2003] raise several issues about our analysis of normalized difference vegetation index (NDVI) data for areas north of 30 N between 1981 and 1999. As we describe below, their comments represent a basic misunderstanding of the data, a misrepresentation of our work, or an anticipation of our recently published results. Here we address these issues in order in which they are given by Lanfredi et al.