毛乌素沙地植被物候时空变化特征及其影响因素

利用MODIS归一化植被指数(NDVI)对2001-2013年毛乌素沙地植被物候的时空变化进行了研究,并分析了物候与海拔、气候的关系。结果显示:(1)毛乌素沙地植被生长开始期(SOG)集中在第90～156天,生长结束期(EOG)在第245～323天,生长季长度(LOG)118～200 d;从东到西,SOG逐渐推迟,LOG逐渐缩短;随着海拔的升高,SOG显著推迟,EOG提前,LOG显著缩短。(2)2001-2013年,毛乌素沙地植被SOG明显提前,变化幅度为9 d/10a(R=-0.46,p=0.06),EOG和LOG分别呈提前和延长趋势,但变化都不显著。(3)研究区植被物候与温度的相关性不明显,但较多受降水量的影响,SOG与春季降水量的相关系数为-0.58(p=0.02);EOG与秋季降水量的相关系数为0.42(p=0.07);LOG与秋季降水量的相关系数为0.48(p=0.05)。

Spatiotemporal Variation of Vegetation Phenology and Its Affecting Factors in the Mu Us Sandy Land

Based on NDVI from MODIS, this paper analyzed the spatiotemporal changes in vegetation phenology in the Mu Su Sandy Land from 2001 to 2013, and the response of the phenology and elevation, climatic factors. The results are enumerated as follows: (1) From 2001 to 2013, the start of growth season (SOG) was concentrated in 90-156 Julian day, the end of growth season (EOG) was in 245-323 Julian day, and the length of growth season (LOG) was in 118-200 Julian day. Elevation played an important role in the regional differentiation of phenology, with the increase of altitude, SOG significantly delayed, EOG advanced, and LOG significantly shortened. (2) From 2001 to 2013, SOG of vegetation came obviously earlier by nine days per decade (R=-0.46, p=0.06), EOG was early and LOG lengthened, but with no significance. (3) Vegetation phenology in the study area was mainly affected by precipitation, but with no apparent correlation with temperature. The correlation coefficient of SOG and spring precipitation was -0.58 (p=0.02), the correlation coefficient of EOG and autumn precipitation was 0.42 (p=0.07), and the correlation coefficient of LOG and autumn precipitation was 0.48 (p=0.05).