Influences of Climate Change and Human Activities on NDVI Changes in China

Liu, Yu; Tian, Jiyang; Liu, Ronghua; Ding, Liuqian

doi:10.3390/rs13214326

Cited by 46 publications

(36 citation statements)

References 90 publications

(98 reference statements)

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“…The NDVI in northeastern East Asia showed an increasing trend during 1982-2014, which is consistent with the study of Sun et al (2021) [60] and Liu et al (2021) [61], and we further found a significant change in NDVI growth rate in northern East Asia around 1998, showing a trend of slowing down during 1998-2014. It has been shown that NDVI changes are closely related to temperature and precipitation [62].…”

Section: Discussionsupporting

confidence: 92%

Trend Changes of the Vegetation Activity in Northeastern East Asia and the Connections with Extreme Climate Indices

et al. 2022

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In the context of global warming, vegetation activity in northeastern East Asia (40–45°N, 105–130°E) (NEA) shows a significant growth trend on a multidecadal scale, but how vegetation changes on a decadal scale is unclear. In this study, we find a significant trend of vegetation greening in northeastern East Asia during 1982–1998 and a slowdown in the greening trend during 1998–2014. Trend analysis of the extreme climate indices reveals that the trends of precipitation-related extreme climate indices are similar to those of vegetation change, and further correlation analysis reveals that precipitation-related extreme climate indices have a strong positive correlation with the NDVI. The results indicate that the vegetation in northeastern East Asia is more sensitive to precipitation changes, especially extreme precipitation, compared with the temperature and related extreme indices. Furthermore, the analysis of large-scale atmospheric circulation changes suggests a role of Northwest Pacific subtropical high (NPSH) in the trend changes of precipitation-related extreme indices. The strengthening of NPSH before 1998 enhances the moisture transport to the NEA, providing abundant water vapor favorable for extreme precipitation events, while after 1998, the NPSH trend is much weakened, corresponding to a decrease in the moisture transport trend.

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Section: Discussionsupporting

confidence: 92%

Trend Changes of the Vegetation Activity in Northeastern East Asia and the Connections with Extreme Climate Indices

et al. 2022

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“…China is located on the northwest coast of Asia and the Pacific Ocean, spanning latitude 3.51-53.34°N and longitude 73.29°E-135.04°E [89]. It is the third largest country in the world, with a land area of approximately 9.6 million square kilometers [13,91]. China has many different types of topography, with terrain that is higher in the west and lower in the east, featuring a three ladder-like distribution [92].…”

Section: Study Domainmentioning

confidence: 99%

“…The SPEI is a drought index that reflects water deficit at different timescales [28], which is suitable for drought monitoring and analysis in the context of climate change [56]. Based on climatic water balance, the SPEI considers the impact of water budget changes, between precipitation and PET (i.e., amount of transpiration and evaporation under sufficient water), on drought behavior [4,91]. The Th model [94] was used to account for the PET effect in this study, due to the simplicity of the calculation process and the accessibility of basic data.…”

Section: Standardized Precipitation Evapotranspiration Indexmentioning

confidence: 99%

Evidence for Intensification in Meteorological Drought since the 1950s and Recent Dryness–Wetness Forecasting in China

Yang

Bing

2022

Atmosphere

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Drought is one of the major environmental stressors; drought is increasingly threatening the living environment of mankind. The standardized precipitation evapotranspiration index (SPEI) with a 12-month timescale was adopted to monitor dry–wet status over China from 1951 to 2021. The modified Mann–Kendall (MMK) and Pettitt tests were used to assess the temporal trend and nonlinear behavior of annual drought variability. The analysis focuses on the spatio-temporal structure of the dry–wet transition and its general connections with climate change processes. In addition, the seasonal autoregressive integrated moving average (SARIMA) model was applied to forecast the dry–wet behavior in the next year (2022) at 160 stations, and the hotspot areas for extreme dryness–wetness in China were identified in the near term. The results indicate that the dry–wet climate in China overall exhibits interannual variability characterized by intensified drought. The climate in the Northeast China (NEC), North China (NC), Northwest China (NWC), and Southwest China (SWC) has experienced a significant (p < 0.05) drying trend; however, the dry–wet changes in the East China (EC) and South Central China (SCC) are highly spatially heterogeneous. The significant uptrend in precipitation is mainly concentrated to the west of 100° E; the rising magnitude of precipitation is higher in Eastern China near 30° N, with a changing rate of 20–40 mm/decade. Each of the sub-regions has experienced significant (p < 0.01) warming over the past 71 years. Geographically, the increase in temperature north of 30° N is noticeably higher than that south of 30° N, with trend magnitudes of 0.30–0.50 °C/decade and 0.15–0.30 °C/decade, respectively. The response of the northern part of Eastern China to the warming trend had already emerged as early as the 1980s; these responses were earlier and more intense than those south of 40° N latitude (1990s). The drying trends are statistically significant in the northern and southern regions, bounded by 30° N, with trend magnitudes of −0.30–−0.20/decade and −0.20–−0.10/decade, respectively. The northern and southwestern parts of China have experienced a significant (p < 0.05) increase in the drought level since the 1950s, which is closely related to significant warming in recent decades. This study reveals the consistency of the spatial distribution of variations in precipitation and the SPEI along 30° N latitude. A weak uptrend in the SPEI, i.e., an increase in wetness, is shown in Eastern China surrounding 30° N, with a changing rate of 0.003–0.10/decade; this is closely associated with increasing precipitation in the area. Drought forecasting indicates that recent drying areas are located in NWC, the western part of NC, the western part of SWC, and the southern part of SCC. The climate is expected to show wetting characteristics in NEC, the southeastern part of NC, and the eastern part of EC. The dry–wet conditions spanning the area between 30–40° N and 100–110° E exhibit a greater spatial variability. The region between 20–50° N and 80–105° E will continue to face intense challenges from drought in the near future. This study provides compelling evidence for the temporal variability of meteorological drought in different sub-regions of China. The findings may contribute to understanding the spatio-temporal effect of historical climate change on dry–wet variation in the region since the 1950s, particularly in the context of global warming.

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“…However, the regions above 3,800 m are mainly located in the northwest of Maqu County, where some literatures indicate that the region is vulnerable to climatic effects (Wu et al, 2019;Yang et al, 2021). In addition, soil water-salt is more sensitive at lower elevations than at higher elevations, probably because lower elevations are more susceptible to human activities (Liu et al, 2021). Therefore, the specific intrinsic mechanism need to be further explored.…”

Section: Influence Of Topography On Soil Water-saltmentioning

confidence: 99%

Spatiotemporal dynamics of soil water-salt and its topographic gradient effects on Alpine area over the Northeastern Tibetan Plateau, China

Zhang

Nian

Adingo

et al. 2022

Front. Environ. Sci.

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Soil water–salt variations at different spatiotemporal scales and their influencing factors are essential for regional vegetation restoration and management. However, the study of soil water–salt of the alpine area has not taken into account the effect of topography, especially in the long time series. This work investigated the spatiotemporal characteristics of water and salt in topsoil from 2000 to 2021, using regression analysis of on-site data and MODIS products. The heterogeneity and trends of soil water–salt in various topographic factors (elevation, slope, and aspect) were also explored by selecting the maximum area of each gradient factor as the constrained condition with the help of ArcGIS software. The results revealed that 1) the models applied to SWC (soil water content), EC (electrical conductivity), and pH utilizing vegetation indices were suitable for estimating the spatiotemporal variations of soil water–salt. 2) Soil water–salt exhibited local aggregation characteristics with an upward trend in SWC and a downward trend in EC and pH as a whole. 3) Mean annual SWC peaked at 3,400–3,800 m with increasing elevation and trended downward with increasing slope. The aspect of mean annual SWC was characterized by lower values in the southwest and south and higher values in the north, while the results for pH were reversed. The slope had a greater influence on EC than on SWC and pH. 4) The trend change of SWC, EC, and pH fluctuated at 2000–2,400 m and >4,600 m with a clear inflection point at 4°–8° and 20°–24°, respectively. In summary, the effects of topography responded to the distribution and trends of soil water–salt. The results have significant implications for implementing ecological improvements in regions with complicated topography and can serve as a reference for formulating future ecological policies.

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Influences of Climate Change and Human Activities on NDVI Changes in China

Cited by 46 publications

References 90 publications

Trend Changes of the Vegetation Activity in Northeastern East Asia and the Connections with Extreme Climate Indices

Trend Changes of the Vegetation Activity in Northeastern East Asia and the Connections with Extreme Climate Indices

Evidence for Intensification in Meteorological Drought since the 1950s and Recent Dryness–Wetness Forecasting in China

Spatiotemporal dynamics of soil water-salt and its topographic gradient effects on Alpine area over the Northeastern Tibetan Plateau, China

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