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应用生态学报 ›› 2024, Vol. 35 ›› Issue (11): 2992-3004.doi: 10.13287/j.1001-9332.202410.022

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2001—2020年全球植被对极端气候的响应

焦鹏华1, 牛健植1,2,3,4*, 苗禹博1,5, 李君宜1, 王迪1   

  1. 1北京林业大学水土保持学院, 北京 100083;
    2林木资源高效生产全国重点实验室, 北京 100083;
    3水土保持与荒漠化防治国家林业局重点实验室, 北京 100083;
    4北京林业大学林业生态工程教育部工程研究中心, 北京 100083;
    5国家林业和草原局林草调查规划院, 北京 100013
  • 收稿日期:2024-02-05 修回日期:2024-07-21 出版日期:2024-11-18 发布日期:2025-05-18
  • 通讯作者: *E-mail: nexk@bjfu.edu.cn
  • 作者简介:焦鹏华, 女, 1998年生, 硕士研究生。主要从事植被与极端气候研究。E-mail: jph309u7@163.com
  • 基金资助:
    国家重点研发计划项目(2022YFF1300804)

Global vegetation response to extreme climate from 2001 to 2020

JIAO Penghua1, NIU Jianzhi1,2,3,4*, MIAO Yubo1,5, LI Junyi1, WANG Di1   

  1. 1School of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, China;
    2State Key Laboratory of Efficient Production of Forest Resources, Beijing 100083, China;
    3Key Laboratory of State Forestry Administration on Soil and Water Conservation and Desertification Combating, Beijing 100083, China;
    4Engineering Research Center of Forestry Ecological Engineering of Ministry of Education, Beijing Forestry University, Beijing 100083, China;
    5Academy of Forestry Inventory and Planning, National Forestry and Grassland Administration, Beijing 100013, China
  • Received:2024-02-05 Revised:2024-07-21 Online:2024-11-18 Published:2025-05-18

摘要: 探究全球植被与极端气候的时空变化和响应特征,对于应对全球气候变化和提高生态系统的稳定性具有重要意义。本研究基于欧洲中期天气预报中心的ERA5气候数据和MODIS归一化植被指数(NDVI)数据,运用Sen’s趋势分析、相关性分析和随机森林回归模型等方法,探究2001—2020年全球5种植被类型(北方森林和温带森林、热带森林、其他木本植被、草原、农田)NDVI对23个极端气候指数的响应特征。结果表明: 研究期间,全球NDVI总体呈增长趋势,增长趋势最显著的植被类型为北方森林和温带森林,最不显著的是农田。极端气候指数方面,除少部分极端高温和低温指数呈降低趋势外,其余指数均呈增长趋势。在不同植被区,对NDVI影响最大的极端气候指数不同。相关性分析表明,在北方森林和温带森林、热带森林、其他木本植被、草原和农田区域,对NDVI影响最大的指数分别为冷昼日数、结冰天数、年降水总量、年降水总量、年降水总量;随机森林结果显示,对各植被区NDVI影响最大的指数分别为冷昼日数、热夜日数、霜冻天数、暖昼日数和寒冷时间持续指数。两种方法结果不同的原因在于相关性分析只反映变量间的线性关系,而随机森林回归模型可以捕捉更复杂的非线性关系。以上研究结果体现了全球植被对极端气候的响应具有显著的区域差异性和复杂性,这种差异性和复杂性可能是不同气候因子交互作用的结果。

关键词: 极端气候, 全球植被, 归一化植被指数, 随机森林, 相关分析

Abstract: Exploring the spatiotemporal variations and response characteristics of global vegetation and extreme climate is of great significance for addressing global climate change and improving ecosystem stability. Based on ERA5 climate data from the European Centre for Medium-Range Weather Forecasts and MODIS normalized difference vegetation index (NDVI) data, we used Sen’s trend analysis, correlation analysis, and random forest regression model to explore the responses of NDVI of five vegetation types (boreal and temperate forest, tropical forest, other woody vegetation, grassland, and cropland) to 23 extreme climate indices from 2001 to 2020. The results showed that global NDVI showed an overall increasing trend from 2001 to 2020. The areas with the most significant growth trend was boreal and temperate forest, and the least significant growth trend occurred in cropland. In terms of extreme climate index, except for a few extreme high temperature and low temperature indices, the other indices showed an increasing trend. Across different vegetation areas, the extreme climate index that had the greatest influence on NDVI was different. The results of correlation analysis showed that the indices with the greatest impact on NDVI in the boreal and temperate forest, tropical forest, other woody vegetation, grassland, and cropland were cold days, ice days, annual total precipitation, annual total precipitation, and annual total precipitation, respectively. The results of random forest analysis showed that the indices with the greatest impact on NDVI in each vegetation zone were cold days, warm night days, frost days, warm days, and the cold spell duration index, respectively. The reason for the different results between the two methods was that correlation analysis only reflected linear relationships between variables, while the random forest regression model could capture more complex nonlinear relationships. Our results showed that the response of global vegetation to extreme climate had significant regional differences and complexities, which may result from interactions between different climate factors.

Key words: extreme climate, global vegetation, normalized difference vegetation index, random forest, correlation analysis