Spatial and Temporal Patterns of Global NDVI Trends: Correlations with Climate and Human Factors

Abstract

Changes in vegetation activity are driven by multiple natural and anthropogenic factors, which can be reflected by Normalized Difference Vegetation Index (NDVI) derived from satellites. In this paper, NDVI trends from 1982 to 2012 are first estimated by the Theil-Sen median slope method to explore their spatial and temporal patterns. Then, the impact of climate variables and human activity on the observed NDVI trends is analyzed. Our results show that on average, NDVI increased by 0.46 × 10 1982-2004, 1995-2004, and 2005-2012, respectively. A positive partial correlation of NDVI and temperature is observed in the first period but it decreases and occasionally becomes negative in the following periods, especially in the Humid Temperate and Dry Domain Regions. This suggests a weakened effect of temperature on vegetation growth. Precipitation, on the other hand, is found to have a positive impact on the NDVI trend. This effect becomes stronger in the third period of 1995-2004, especially

Towards an Improved Environmental Understanding of Land Surface Dynamics in Ukraine Based on Multi-Source Remote Sensing Time-Series Datasets from 1982 to 2013

“…We used a subtractive model for visualization, where the primary factors are illustrated with a pure color and the overlapping areas of influence are depicted by the intersection of colors. Although the studies have discussed the impact of climatic variation on land surface changes [33,55,56], very few of them have focused on the impact of environmental factors on land surface trends in Ukraine as opposed to management and land tenure factors [1][2][3][4][5][6][7][8]. Our results show that the changes in land surface can be partially explained by the combination of thermal and water conditions.…”

Ecohydrological optimality in the Northeast China Transect

“…Studies of the relationship between climate factors and vegetation growth conditions reveal that precipitation and temperature are the two dominant factors that affect M * Liu and Li, 2015). Under this framework, the variation of precipitation (P τ ) affects the availability of water, thus changing water supply curve; air temperature (t a ) affects not only water supply but also water demand, through changing resistance ratio and evaporation (Fig.…”

Detecting Spatial and Temporal Change of NDVI Dynamics in the Mekong River Basin: Relationship with Anthropogenic Effects

“…Analysis of land vegetation response to the disturbance, both climate and human disturbance, is essential element which allows better understanding of the disturbance effect on ecosystems in the changing world [1], [2]. Yet many previous researches mainly focused on climate effect on vegetation dynamics, and found that climate contributors, such as temperature, precipitation, and soil moisture, to vegetation change are important for many regions [3]- [6], which is included the MRB [2] and its sub-basin [7].…”

“…Beside climate effect on vegetation in the MRB, human activities such as land use change, population growth [9], fertilization, irrigation etc. could also impact to NDVI trend [1]. Unfortunately, it is not clear how human activities affect NDVI trend and how their effects evolve over time in the MRB.…”