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

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.

Keywords

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