2.4.3. Time Lag Analysis

The EVI sequence (May–September) and the monthly mean air temperature in the growing season of the study area from 2000 to 2015 were used as two sets of variables to calculate GRG between EVI sequence and the monthly mean air temperature. Similarly, the GRG between EVI sequence in the growing season and the monthly mean air temperature (April–August, March–July and February–June) could be calculated, and that between the monthly mean relative humidity and the monthly cumulative precipitation (May–September, April–August, and March–July, February–June) could also be calculated respectively. By comparing the GRG between EVI in the growing season and different comparative factor sequence, the authors further discuss the time lag effect of EVI for climatic factors.
