6R B Myneni,C D Keeling,C J Tucker,et al.Increased plantgrowth in the northern high latitudes from 1981 to 1991[J].Na-ture,1997,386:698-702.
7E E Cleland,I Chuine,A Menzel,et al.Shifting plant phenology inresponse to global change[J].Trends in Ecology Evolution,2007,22:357-365.
8J Peuelas,I Filella.Responses to a Warming World[J].Science,2001,294:793-795.
9M A White,F Hoffman,W W Hargrove,et al.A global frameworkfor monitoring phenological responses to climate change[J].Geo-phys.Res.Lett.,2005,32:L04705.
10B C Reed,J F Brown,D VanderZee,et al.Measuring phenologicalvariability from satellite imagery[J].Journal of Vegetation Science,1994,5:703-714.