Effects of Environmental Factors on the Changes in MODIS NPP along DEM in Global Terrestrial Ecosystems over the Last Two Decades

Zhaoqi Wang,Lina Wang,Hong Wang,Tongfang Wang,Xiaotao Huang,Kai Zheng,Xiang Liu

doi:10.3390/rs14030713

Abstract

Global warming has exerted widespread impacts on the terrestrial ecosystem in the past three decades. Vegetation is an important part of the terrestrial ecosystem, and its net primary productivity (NPP) is an important variable in the exchange of materials and energy in the terrestrial ecosystem. However, the effect of climate variation on the spatial pattern of zonal distribution of NPP has remained unclear over the past two decades. Therefore, we analyzed the spatiotemporal patterns and trends of MODIS NPP and environmental factors (temperature, radiation, and soil moisture) derived from three sets of reanalysis data. The moving window method and digital elevation model (DEM) were used to explore their changes along elevation gradients. Finally, we explored the effect of environmental factors on the changes in NPP and its elevation distribution patterns. Results showed that nearly 60% of the global area exhibited an increase in NPP with increasing elevation. Soil moisture has the largest uncertainty either in the spatial pattern or inter-annual variation, while temperature has the smallest uncertainty among the three environmental factors. The uncertainty of environmental factors is also reflected in its impact on the elevation distribution of NPP, and temperature is still the main dominating environmental factor. Our research results imply that the carbon sequestration capability of vegetation is becoming increasingly prominent in high-elevation regions. However, the quantitative evaluation of its carbon sink (source) functions needs further research under global warming.

Highlights

Introduction published maps and institutional affilSince the nineteenth century, the global near-surface temperature has continued to increase according to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC)
The spatial pattern of mean annual net primary productivity (NPP) is consistent with our perception that tropical forests have the highest NPP, while NPP is relatively low in alpine and arid regions (Figure 3a)
Our research shows that nearly 60% of the global area exhibits an increase in NPP with increasing elevation, which means that vegetation in high-elevation areas plays an increasingly prominent role in absorbing atmospheric CO2 and mitigating climate change

Summary

Introduction

The global near-surface temperature has continued to increase according to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC). The widespread impact of global warming has caused a series of negative ecological consequences, such as drought [1,2], melting [3], rising sea levels [4], and frequent extreme climates [5,6]. The accelerating global warming has become a major challenge that is restricting the sustainable development of human society [7,8,9]. Vegetation is an important part of the terrestrial ecosystem and plays a crucial role in sequestering carbon and mitigating climate change [10]. The vegetation ecosystem is found to be more vulnerable and sensitive to climate change than the other ecosystems

Methods

Results

Discussion

Conclusion