关键词: 植被物候, 时空变化, 地形差异, 山西省

Abstract: To clarify the vegetation phenology characteristics in Shanxi Province, we reconstructed the MODIS NDVI time series from 2000 to 2015 by adopting the Double Logistic fitting method, extracted vegetation phenology using the dynamic threshold method, and then analyzed temporalspatial variations of phenology and the effects of topography on phenological changes. The results showed that phenology in Shanxi Province changed significantly from 2000 to 2015. The start of the growing season (SOS) was advanced by about 0.7 d per year (R²=0.665, P<0.01). The end of the growing season (EOS) was delayed by about 1.5 days per year (R²=0.601, P<0.001). The length of the growing season (LOS) was extended by about 2.2 days per year (R²=0.772, P<0.001). The phenological change rate varied with different vegetation types. Grasslands showed the highest rate of SOS changes, followed by crops and then forestland. Forestland had the highest change rate of EOS, followed by crops and grassland. Forestland had the highest change rate of LOS, followed by grassland and then crops. There were substantial spatial variations in vegetation phenology. From low latitude to high latitude and from west to east, the SOS was delayed, EOS was advanced, and LOS was shortened. Vegetation phenology was significantly different across altitudes, slope aspects, and slope degrees. Vegetation phenology changed significantly with altitude below 1200 m. At higher altitude, SOS was significantly delayed, EOS significantly was advanced, and LOS was significantly shortened. Compared with shade slope, SOS at sunny slope was advanced by about 1 d, the EOS was delayed by about 0.8 d, and the LOS was extended by about 1.8 d. In areas with slope less than 16°, SOS was advanced, EOS wasdelayed, and LOS was extended with the increases of slope. Our results indicate that vegetation phenology varies greatly over a long time span and topography is a crucial factor influencing the spatial pattern of phenology.

Key words: vegetation phenology, temporal-spatial change, spatial difference, Shanxi Province.