黄土高原植被对气候变化的时滞响应及其时变特征

马雄伟 赵庆志 姚顽强

摘 要：为研究黄土高原（Loess Plateau，LP）地区不同土质类型植被对气候因子变化的时滞响应及时变特征，选取LP地区实测氣象数据（包括温度和降雨）和MOD13 A3归一化植被指数（Normalized Difference Vegetation Index，NDVI）作为实验数据，利用线性趋势分析、Mann-Kendall（M-K）突变分析及皮尔逊相关性等方法对LP地区不同土质类型区域植被与气候之间的相关性进行定量分析，实验发现：由于人类活动导致LP地区的河流冲积平原土地利用情况发生变化且植被不断减少，其余区域植被均呈现显著上升趋势;由M-K趋势分析发现LP地区1981—2016年温度总体呈显著上升趋势，但2000—2016温度上升趋势不显著;2000年LP地区实施“退耕还林”政策后，该地区温度上升速率减缓，降雨量增多（特别是在3月和5月）;LP地区NDVI对气候因子存在不同时长的滞后效应，且区域性差异较大。NDVI对温度无滞后响应区域和1月滞后响应区域分别占LP区域37.5%和62.5%，NDVI对降雨的滞后响应时常为1～3月，分别占LP区域的62.5%，25%和12.5%.上述发现有助于进一步理解LP地区不同土质类型区域植被对气候响应的时间尺度，对该地区后续制定生态政策具有重要意义。关键词：黄土高原;Mann-Kendall;时滞效应;时变特征;归一化植被指数中图分类号：P 23

文献标志码：A

文章编号：1672-9315（2020）01-0157-10

DOI：10.13800/j.cnki.xakjdxxb.2020.0121开放科学（资源服务）标识码（OSID）：

Time lags of vegetation to climate change and

temporal characteristics in Loess Plateau

MA Xiong-wei，ZHAO Qing-zhi，YAO Wan-qiang

（College of Geomatics，Xian University of Science and Technology，Xian 710054，China）Abstract：In order to investigate the time-lag responses of vegetation of different soil types to climate factors and the characteristics of spatiotemporal variation of vegetation in the Loess Plateau（LP）region，the observed meteorological data，（like temperature and precipitation）and Normalized Difference Vegetation Index（NDVI）were selected in this paper as the experimental data.Methods include the linear regression trend，the Mann-Kendall（M-K）mutation，the conspicuous testing，and the Pearson Correlation Coefficient（PCC）is used to analyze the relationship between vegetation and climate of different soil types region in LP area.Results show that the land-use had changed，and vegetation was decreased due to the human activities in the River Impact Plain.The vegetation in other regions of the LP showed a significant upward trend.The results of M-K trend analysis shows that the temperature showed a significant upward trend from 1981 to 2016 in LP area，but the temperature from 2000 to 2016 showed no significant upward trend.The rising rate of temperature in the LP area has been slowed down and rainfall increased（especially in March and May）after the policy of“Grain for Green Project” implemented in 2000.The time lag of NDVI response to the climate in the LP region exists，which had significant differences in diverse areas.The non-lag and the one-month lag area of NDVI to temperature response accounted for 37.5% and 62.5% of the LP area，respectively.The lag response of NDVI to precipitation was usually 1～3 months，accounting for 62.5%，25%，and 12.5% of the LP area，respectively.The above findings help understand further the time scale of vegetation response to different soil types in LP，which is of vital significance for the development of regional ecological policies in the future.Key words：Loess Plateau;Mann-Kendall;time lags;time-varying characteristics;NDVI

0 引 言

全球气候变化是20世纪以来陆地生态系统变化的重要因素之一[1-2]，研究陆地生态系统对气候因子的时空响应具有重要意义。联合国政府间气候变化专门委员会（Intergovernmental Panel on Climate Change，IPCC）指出，在过去的一个世纪里，全球气温不断升高且有持续增加的趋势，这是导致极端气候（如极端高温、极端降水和极端干旱等）频发的主要原因[3-4]。……