title: Complex responses of spring alpine vegetation phenology to snow cover dynamics over the Tibetan Plateau, China.
abstract: Snow cover dynamics are considered to play a key role on spring phenological shifts in the high-latitude, so investigating responses of spring phenology to snow cover dynamics is becoming an increasingly important way to identify and predict global ecosystem dynamics. In this study, we quantified the temporal trends and spatial variations of spring phenology and snow cover across the Tibetan Plateau by calibrating and analyzing time series of the NOAA AVHRR-derived normalized difference vegetation index (NDVI) during 1983-2012. We also examined how snow cover dynamics affect the spatio-temporal pattern of spring alpine vegetation phenology over the plateau. Our results indicated that 52.21% of the plateau experienced a significant advancing trend in the beginning of vegetation growing season (BGS) and 34.30% exhibited a delaying trend. Accordingly, the snow cover duration days (SCD) and snow cover melt date (SCM) showed similar patterns with a decreasing trend in the west and an increasing trend in the southeast, but the start date of snow cover (SCS) showed an opposite pattern. Meanwhile, the spatial patterns of the BGS, SCD, SCS and SCM varied in accordance with the gradients of temperature, precipitation and topography across the plateau. The response relationship of spring phenology to snow cover dynamics varied within different climate, terrain and alpine plant community zones, and the spatio-temporal response patterns were primarily controlled by the long-term local heat-water conditions and topographic conditions. Moreover, temperature and precipitation played a profound impact on diverse responses of spring phenology to snow cover dynamics.
authors.affiliation: Key Laboratory of Digital Earth, Institute of Remote Sensing and Digital Earth, Chinese Academy of Science, Beijing 100101, China. Electronic address: w_siyuan@126.com.
authors.forename: Siyuan
authors.initials: S
authors.lastname: Wang
authors.affiliation: Key Laboratory of Digital Earth, Institute of Remote Sensing and Digital Earth, Chinese Academy of Science, Beijing 100101, China.
authors.forename: Xiaoyue
authors.initials: X
authors.lastname: Wang
authors.affiliation: Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6301, USA.
authors.forename: Guangsheng
authors.initials: G
authors.lastname: Chen
authors.affiliation: Pacific Northwest National Laboratory, 5825 University Research Court, Suite 1200, College Park, MD 20740, USA.
authors.forename: Qichun
authors.initials: Q
authors.lastname: Yang
authors.affiliation: School of Civil Engineering, Beijing Jiaotong University, Beijing 100044, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Wang
authors.affiliation: Key Laboratory of Digital Earth, Institute of Remote Sensing and Digital Earth, Chinese Academy of Science, Beijing 100101, China.
authors.forename: Yuanxu
authors.initials: Y
authors.lastname: Ma
authors.affiliation: Key Laboratory of Digital Earth, Institute of Remote Sensing and Digital Earth, Chinese Academy of Science, Beijing 100101, China.
authors.forename: Ming
authors.initials: M
authors.lastname: Shen
mesh_terms: D002681:China; D017753:Ecosystem; D063245:Plant Development; D012621:Seasons; D012914:Snow; D062211:Spatio-Temporal Analysis; D013696:Temperature; D018609:Tibet
keywords: Alpine vegetation; Normalized difference vegetation index (NDVI); Snow cover; Spring phenology; The Tibetan Plateau