Abstract:

In order to understand the vegetation phenological variation of Zhejiang Province comprehensively and further improve the vegetation response to climate change mechanism, the vegetation phenological metrics (the beginning data, the ending data and length of growing season) and its spatio-temporal variation in Zhejiang Province were analyzed, based on the reconstructed MODIS NDVI time-series using the improved Savitzky-Golay filter. To explore the vegetation phenology from 2001 to 2010, a polynomial fitting and dynamic threshold method were utilized. The results showed that vegetation growing season of Zhejing Province started in late March and ended in mid November, the average length of growing season was about 222 days. In past 10 years, the beginning time of growing season expressed the advance trend, but not significant, while the ending time was significantly delayed, the length of growing season was extended, about 7 days every 10 years. The spatial pattern of the begging time of growing season was embodied by transition from south to north, the ending time was relatively concentrated. Vegetation growing season of extended area was similar of the shortened area. Phenological characteristics of different vegetation types showed great differences. Coniferous forest and shrub grassland of the typical vegetation phenological changes were analyzed, the NDVI variation of shrub grassland was larger than coniferous forest both in annual and inner-annual. Coniferous forest growth season was shorter than the shrub grassland about 35 days, and extension of the trend, while shrub grass growing season changed not obviously.