摘要:植被物候直接反映了植被对环境变化响应的动态过程，对研究植被与气候的关系具有重要意义。基于遥感植被时序数据，探讨秦巴山区典型山地-米仓山地区植被物候变化及其对气候的响应。利用MODIS NDVI时序数据，采用动态阈值法获取米仓山地区植被物候参数；借助于Theil Sen斜率、Mann Kendall趋势检验方法结合植被类型数据分析研究区物候时空变化；采用偏相关方法分析物候变化与气温和降水之间的关系。结果表明：（1）米仓山地区植被生长季始期（SOS）主要集中在第80-110d，海拔每上升100m，SOS大约推迟0.6d；生长季末期（EOS）主要集中在第250-300d；生长季长度（LOS）主要集中在130-210d。除低海拔区域受人类活动影响物候波动较大外，EOS和LOS随海拔变化存在2000m分界线，其下物候随海拔升高物候明显推迟或缩短，其上物候变化趋于平缓。（2）16a来植被SOS呈提前趋势，提前幅度为0.47d/a，提前的像元占74.03%，其中，达到显著提前的像元占12.21%（P<0.1）；EOS整体呈提前趋势，提前幅度为0.22d/a；LOS略有延长，延长幅度为0.26d/a。（3）区域常绿型森林植被SOS晚于同垂直带的落叶型森林植被；草地、常绿阔叶灌木林SOS提前趋势最明显，变化率分别为-0.80、-0.71d/a；EOS提前趋势最明显的是针阔混交林和落叶阔叶林。（4） SOS主要受3月平均气温和4月降水的影响，3月平均气温升高以及4月降水增加导致SOS提前；EOS主要受10月降水的负向影响。



Abstract:Vegetation phenophase directly reflects the dynamic process of vegetation response to environmental changes, and is of great importance to understand the relationship between vegetation and climate. This paper explored the spatiotemporal variability of vegetation phenophase and its response to climate changes in Micang Mountains, a classic example of Qinling-Daba Mountains, China. Based on the MODIS NDVI data from 2003 to 2018, the vegetation phenological parameters of the Micang Mountains were obtained by the Savitzky-Golay filtering method and the dynamic threshold method. The Theil Sen slope and Mann-Kendall trend test, combined with vegetation types, were used to analyze quantitatively the temporal and spatial variation of phenophase. The relations between vegetation phenological periods and monthly temperature and precipitation were explored also by partial correlation analysis. The results showed that the start of the growing season (SOS) ranged mainly from 80^th to 110^th day, and it delayed with the increasing elevation about 0.6 day every 100 m. The end of the growing season (EOS) ranged mainly from 250^th to 300^th day. The length of the growing season (LOS) ranged mainly from 130 to 210 day. The EOS and LOS had 2000 m boundary with the elevation changes, except for low-altitude areas where the phenophase fluctuated greatly affected by human activities. The phenophase below it significantly delayed or shortened with the elevation, and the phenological changes above it tended to be gentle. The SOS showed an advanced trend with 0.47 d/a, accounting for 74.03% of the total area, and significantly advanced area accounted for 12.21% (P<0.1). The EOS showed an early trend totally with an advanced range of 0.22 d/a too. The LOS slightly extended with a rate of 0.26 d/a. The SOS of evergreen forest vegetation was later than that of deciduous forest vegetation in the same vertical belt. The advanced trends of SOS in grassland and evergreen broad-leaved shrub forest were the most obvious, and their changed rates were -0.80 d/a and -0.71 d/a, respectively. The most obviously advanced trend of EOS appeared in the coniferous and broad-leaved mixed forest and deciduous broad-leaved forest. The relation analysis revealed that the SOS was mainly affected by temperature in March and precipitation in April because the increased temperature and precipitation led to advance of SOS, and that the EOS was negatively influenced by precipitation in October that caused advance of EOS in Micang Mountains.





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