收藏设为首页 广告服务联系我们在线留言

干旱区地理 ›› 2022, Vol. 45 ›› Issue (5): 1523-1533.doi: 10.12118/j.issn.1000-6060.2021.017

• 生物与土壤 • 上一篇    下一篇

毛乌素沙地东南缘植被NDVI时空变化及其对气候因子的响应

贺军奇(),魏燕,高万德,陈云飞,马延东,刘秀花()   

  1. 长安大学水利与环境学院,旱区地下水文与生态效应教育部重点实验室,国家林业和草原局黄土高原水土保持与生态修复重点实验室,陕西 西安 710054
  • 收稿日期:2022-01-10 修回日期:2022-03-12 出版日期:2022-09-25 发布日期:2022-10-20
  • 通讯作者: 刘秀花
  • 作者简介:贺军奇(1978-),男,博士,副教授,主要从事水文生态学研究. E-mail: 516588675@qq.com
  • 基金资助:
    国家自然科学基金项目(41877179);国家自然科学基金项目(41901034);陕西水利科技计划项目(2019s1kj-18);中央高校基本科研业务费项目(300102292904)

Temporal and spatial variation of vegetation NDVI and its response to climatic factors in the southeastern margin of Mu Us Sandy Land

HE Junqi(),WEI Yan,GAO Wande,CHEN Yunfei,MA Yandong,LIU Xiuhua()   

  1. School of Water and Environment, Chang’an University, Key Laboratory of Subsurface Hydrology and Ecological Effect in Arid Region, Ministry of Education, Key Laboratory of Soil and Water Conservation and Ecological Restoration on the Loess Plateau of National Forestry and Grassland Administration, Xi’an 710054, Shaanxi, China
  • Received:2022-01-10 Revised:2022-03-12 Online:2022-09-25 Published:2022-10-20
  • Contact: Xiuhua LIU

摘要:

了解植被生长对气候变化的响应是厘清生态系统动态关系的重点。基于1990—2018年气象数据和归一化植被指数(NDVI),应用偏相关分析与地理探测器等方法,分析了在生长季,毛乌素沙地东南缘不同类型植被年均NDVI的变化趋势,探讨了年均气温与年总降水量对各类型植被的影响。结果表明:(1) 1990—2018年生长季研究区植被年均NDVI显著与极显著增加面积达97.9%,整体生态环境质量大幅度改善。2005年之前植被年均NDVI增速缓慢,此后以0.011·a-1的速率发生了突变增加,其中灌丛类植被年均NDVI增长幅度最大。(2) 2000年为年总降水量与年均气温的趋势突变点,突变前年总降水量以-5.510 mm·a-1的速率减少,此后以5.541 mm·a-1的速率增加,且主要依赖于大雨雨量的增加;年均高温与年均低温在突变前上升速率分别为0.122 ℃·a-1与0.230 ℃·a-1,突变后,年均高温下降速率为-0.014 ℃·a-1,而年均低温上升速率为0.022 ℃·a-1。(3) 在植被年均NDVI缓慢增长阶段(1990—2005年),年均低温对植被影响较大,与不同类型植被年均NDVI多呈显著正相关;在植被年均NDVI快速增长阶段(2006—2018年),年总降水量与不同类型植被年均NDVI呈显著正相关,大降雨事件的频发使得降水量对于植被的生长起主导作用。年总降水量与年均气温尤其是年均低温的交互作用是促进植被生长的关键。

关键词: 毛乌素沙地, 气候因子, 归一化植被指数(NDVI), 地理探测器, 极点对称模态分解法(ESMD)

Abstract:

A central element in understanding the dynamic relationship between ecosystems is achieved by understanding the response of vegetation growth to climate change. Based on the meteorological data and normalized difference vegetation index (NDVI) from 1990 to 2018, the variation in the NDVI of different types of vegetation in the southeast margin of Mu Us Sandy Land of Shaanxi, China during the growing season was analyzed via use of a partial correlation analysis and geographic detector data, and the effects of temperature and precipitation on various types of vegetation are discussed. The results show that: (1) In the growing seasons from 1990 to 2018, the annual NDVI for vegetation across the whole region increased significantly by 97.9%, and the overall eco-environmental quality was significantly improved. The growth rate of the annual NDVI of vegetation was slow prior to 2005, and then it increased sharply with a rate of increase of 0.011·a-1; across the observed increases, the annual NDVI related to shrub vegetation increased the most. (2) The year 2000 represented a transition year; a significant change in the behavior of the total precipitation and annual air temperature was observed in the year 2000. The total precipitation was seen to decrease at a rate of -5.510 mm·a-1 before this transition year and increase with a rate of 5.541 mm·a-1 after this transition year; these values were dominated by heavy rainfall events. Prior to this abrupt change in the year 2000, the annual rate of increase of annual extreme daily mean temperature and annual minimum daily mean temperature were 0.122 ℃·a-1 and 0.230 ℃·a-1, respectively. After the year 2000, the average annual decreasing rate of annual extreme daily mean temperature was -0.014 ℃·a-1, and the average annual rising rate of annual minimum daily mean temperature was 0.022 ℃·a-1. (3) In the slow growth stage of the NDVI (1990—2005), the annual minimum daily mean temperature was positively correlated with the annual NDVI of different types of vegetation, and had the greatest influence; in the rapid growth stage of annual NDVI (2006—2018), the total precipitation was positively correlated with the annual NDVI of different types of vegetation, and the frequent occurrence of heavy rainfall events meant that the total precipitation had a dominant effect on the growth of vegetation. This work finds that the interaction between total precipitation and annual air temperature, especially the annual minimum daily mean temperature, is the key factor in the promotion of the growth of vegetation.

Key words: Mu Us Sandy Land, climatic factor, normalized difference vegetation index (NDVI), geographic detector, extreme-point symmetric mode decomposition (ESMD)