2001-2020年南盘江流域植被物候时空变化及其对气候的响应

植被物候对气候敏感易观测,是观测生态变化与全球气候变化的重要指标,研究植被物候变化及其对气候的响应对于了解全球气候变化与植被之间的复杂关系具有重要意义。为揭示近20年来南盘江流域植被物候时空变化及其对气候的响应特征,基于2001—2020年增强型植被指数(MOD13Q1-EVI),运用S-G滤波、动态阈值法、Sen斜率分析法、相关性分析法等方法,获取了南盘江流域植被物候参数,分析其时空分布特征,利用偏相关系数分析了气候变化对SOS,EOS的影响。结果表明:(1)2001—2020年,南盘江流域物候特征变化较大,SOS(Start of the growing season)呈提前趋势,EOS(End of the growing season)和LOS(Length of the growing season)呈推迟延长趋势,物候变化具有空间异质性,不同子流域植被物候存在较大差异。(2)植被物候变化受到地形的影响,EOS随海拔升高,结束时间提前; SOS随海拔变化的规律与LOS的规律相反,都存在1 000 m,2 000 m和2 600 m分界线。(3)南盘江流域SOS变化与气温、降水呈正相关关系,EOS与气温呈正相关关系、与降水呈负相关关系。该研究可为南盘江流域的生态环境保护与植被资源可持续发展提供科学依据。

Temporal and Spatial Changes of Vegetation Phenology and Its Response to Climate Change in Nanpan River Basin from 2001 to 2020

Vegetation phenology is sensitive to climate and easy to be observed, which is an important index for observing ecological change and global climate change. It is of great significance for understanding the complex relationship between global climate change and vegetation to study the changes of vegetation phenological and its response to climate. To reveal the spatial and temporal changes of vegetation phenology and its response to climate in the Nanpan River Basin in the past 20 years, based on EVI(MOD13Q1-EVI)of 2001—2020, we took Nanpan River Basin as the study area, obtained the parameters of vegetation phenology and analyzed spatio-temporal distribution characteristics using S-G filter, dynamic threshold method, Sen slope analysis method and correlation analysis method, and analyzed the impact of climate changes on SOS(start of the growing season), EOS(end of the growing season)and LOS(length of the growing season)using partial correlation coefficient. The results showed:(1)from 2001 to 2020, the phenological characteristics of Nanpan River Basin changed greatly, with SOS advancing, EOS and LOS delaying and extending; the phenological changes had spatial heterogeneity, and the phenology of vegetation in different sub-basins was quite different;(2)vegetation phenology changes were affected by terrain, and EOS ended earlier with elevation; the pattern of SOS changing with altitude was opposite to that of LOS, and there were boundaries of 1 000 m, 2 000 m and 2 600 m;(3)the change of SOS in Nanpan River Basin was positively correlated with temperature and precipitation, while EOS was positively correlated with temperature and negatively correlated with precipitation. This study can provide a scientific basis for the ecological environment protection and sustainable development of vegetation resources in the Nanpan River Basin.