渭河流域净初级生产力遥感反演及变化归因分析

Remote sensing inversion of net primary productivity and change attribution analysis in the Weihe River Basin

摘要

【目的】研究旨在探讨2000年实施生态修复政策以来，渭河流域净初级生产力的演化特征，揭示气候变化与人类活动对植被生态的综合作用机制，为流域生态保护与可持续发展提供理论依据。【方法】基于GEE云平台，调用MOD17A3HGF6.1数据，分析NPP、CPP和VPG三类净初级生产力的时空分布格局。通过构建六种植被变化情景，探讨气象因子和人类活动对植被变化的驱动模式，并结合最小二乘回归分析法、Pearson相关系数和贡献指数对各影响因子进行定量评估。【结果】(1)2000—2023年间，渭河流域NPP在年内呈单峰型季节性变化，年际增幅为9.91 gC·m^-2·a^-1,空间分布呈现“南高北低”的格局。(2)在植被恢复过程中，气温和降水与植被生长呈正相关，相关系数分别为0.26和0.43;太阳辐射在以人类活动为主导的植被恢复中呈轻度正相关，相关系数为0.12;人口密度和道路密度对约34.77%的植被恢复区域起促进作用。(3)在植被退化过程中，降水对植被退化的贡献度为30.43%,人口密度和道路密度对植被退化的相关系数分别为0.71和0.64。【结论】研究期间，渭河流域NPP整体呈增长趋势，气温、降水、人口密度和道路密度对NPP的驱动作用显著，太阳辐射的影响相对较弱。气候变化是推动流域植被恢复的主要因素，而生态修复等人类活动措施则有效提升了区域植被的生产力。

Abstract

[Objective] Aiming at revealing the synergistic impacts of climate change and anthropogenic activities on vegetation ecology, the spatiotemporal dynamics of net primary productivity(NPP) in the Weihe River Basin since the implementation of the ecological restoration policy in 2000 are explored, which provide a theoretical basis for the ecological conservation and sustainable development of the region. [Methods] Based on the Google Earth Engine(GEE) cloud platform, MOD17A3HGF6.1 datum are utilized to investigate the spatiotemporal distribution patterns of NPP, CPP, and VPG. By constructing six vegetation change scenarios, it examines the influence mechanisms of climatic factors and human interventions on vegetation changes. The contributions of each factor were quantitatively evaluated using least squares regression, Pearson correlation analysis, and contribution indices. [Results] (1) From 2000 to 2023, NPP in the Weihe River Basin exhibited unimodal seasonal fluctuations, with an average annual increase of 9.91 gC·m^-2·a^-1, and demonstrated a spatial gradient of “higher in the south, lower in the north”.(2) During the vegetation restoration phase, temperature and precipitation were positively correlated with vegetation growth, with correlation coefficients of 0.26 and 0.43, respectively. Solar radiation displayed a marginal positive correlation in vegetation restoration driven by human activity, with a correlation coefficient of 0.12. Population density and road density accounted for approximately 34.77% of the restored vegetative area.(3) In the vegetation degradation phase, precipitation was responsible for 30.43% of the vegetation decline, with correlation coefficients for population density and road density reaching 0.71 and 0.64, respectively. [Conclusion] Throughout the study period, NPP in the Weihe River Basin exhibited a general upward trajectory. Climate variables such as temperature and precipitation, population and road density, exert substantial influence on NPP, while solar radiation has a comparatively limited effect. Climate change emerges as the predominant driver of vegetation restoration, while human interventions such as ecological restoration efforts significantly enhance regional vegetation productivity.

关键词

净初级生产力(NPP) / 气候生产潜力(CPP) / 气候变化 / 人类活动 / 渭河流域 / 影响因素

Key words

net primary productivity(NPP) / climate potential productivity(CPP) / climate change / human activities / Weihe River Basin / influencing factors

基金资助

国家自然科学基金委员会青年科学基金项目(62003313)

河南省重点研发与推广专项(科技攻关)项目(232102241008)